| 10base2 | An ethernet standard for cable. The 10 refers to its 10 Mbps bandwidth, the base to single channel baseband, and the 2 to its 200 meter effective range. It uses thin coaxial cable. |
| 10baseT | An ethernet standard for cable. The 10 refers to its 10 Mbps bandwidth, the base to single channel baseband, and the T to Twisted pair. The cable uses two pairs of unshielded twisted wires. |
| 404 error | Error returned by a browser when it is unable to connect to a remote address. |
| adware | Any software which serves banner ads or pop-up ads to you while in use. It is sometimes installed in freeware or shareware which you download from the nets, and provides one more channel for advertisers to reach you. Some adware will also track your files, net usage, and software and report it back to advertisers to help them channel relevant ads to you. See spyware. |
| afk | Chat abbreviation for "away from keyboard". |
| anti-aliasing | Chat abbreviation for "away from keyboard". |
| B2B | Business to Business. A mode of conducting business between two or more companies over the Internet, rather than more traditional modes such as telephone, mail, and face to face. |
| B2C | Business to Consumer. Another business model over the Internet. |
| B2R | Back to Reality! |
| backbone | A central network connecting other networks together. Formerly a network run by the National Science Foundation for the US, there are now multiple |
| bandwidth | Literally, the frequency width of a transmission channel in Hertz, kiloHertz, megaHertz, etc. Often used as an expression of the amount of |
| bang address | An old system of mail addressing in UUCP networks, where the successive routing addresses were followed by exclamation points (also known as bangs) and the addressee was the last element. |
| baud | Rate of transmission speed in a signal - the number of changes of state, such as voltage or frequency, per second in a signal. Named for the French teleprinter inventor Baudot. In simplest systems, it is synonymous with bits per second. In more complex systems, a baud may include more than one bit. |
| baud rate | A nearly obsolete term for transmission rates synonymous in early, simple systems with bits per second. In faster, more complex systems of encoding and transmitting data, the term loses its simple meaning and has fallen into disuse (and frequent misuse). See baud. |
| Baudot code | The Baudot code, used by early teleprinters, represents letters, numbers, and symbols in five-character binary codes, which includes shifts to increase the number of characters beyond 32. |
| bayonet connector | See BNC |
| bbl | Chat shorthand for "be back later". |
| BBS | Bulletin Board System. A dial-up service offering messages, files, and other services over a modem. BBS were very popular in the 1980s and early 1990s, but have been largely replaced by the Internet. |
| Bcc | Blind Carbon Copy. Unlike the Cc option (Carbon Copy), when the Bcc address option is selected in e-mail, other addressees do not see the Bcc address. |
| beta test | In software development, a stage of testing where the program is tried out with a selected trial audience to find and correct bugs, usually people of similar backgrounds to those expected to use the software. Check out Delphi's Beta Test Forum. Compare to
|
| bfn | Chat shorthand for "bye for now". |
| binary | Binary means the use of only two values, zero and one, in encoding |
| binary files | Binary files are files that include up to 256 different characters |
| bit | Short for binary digit (0 or 1). Lower case b is used in abbreviations to distinguish it from bytes. For example, KBps (thousand bytes per second) is 8 times as great as Kbps (thousand bits per second). |
| bitmap | A graphic which is defined by specifying the colors of dots or pixels which make up the picture. Also known as raster graphics. Common types of bitmap graphics are GIF, JPEG, Photoshop, PCX, TIFF, Macintosh Paint, Microsoft Paint, BMP, PNG, FAX formats, and TGA. |
| blog | Short for web log; usually a chronological record of thoughts, links, events, or actions posted on the web. For examples, see the Yahoo Directory of Weblogs. For another point of view, see John Dvorak's Deconstructing a Blog. |
| BNC, BNC connector | Short for BayoNet Connector or Baby N Connector or Bayonet Neill-Concelman (for the inventors Paul Neill and Carl Concelman who developed the similar N and C connectors separately and the BNC and TNC connectors together). It is also sometimes called a British Naval Connector, although the origin is questionable. A twist-and-lock connector for coaxial cable, BNC connectors are used for electronic equipment and LANs and permit frequencies into the gigaHertz ranges. |
| BOFH | "Bastard Operator From Hell," a classic diary of the ultimate in outrageous system support widely posted on Usenet. Always worth a return visit. |
| bookmark | Just as a paper bookmark is used as a reminder of the page you are on in a book, electronic bookmarks are used to bring you back to a website or other site you may want to return to. The Netscape browser lets you bookmark any site and save the bookmarks in a file you can recall at any time. Microsoft Internet Explorer uses the term "favorite" instead of bookmark for the same concept. |
| Boolean search | A method of searching for information in databases that combines search terms with the operators AND, OR, NOT, and parentheses. See a fuller explanation |
| bot | Short for robot, a program designed to search the Internet looking for information. A common use of bots is the variously named spiders, worms, and crawlers that support search engines by following links from site to site and within a site to dig out information to be indexed by the search engine. Another is the MusicBot |
| bounce | The return of an e-mail message because of an error in its address or delivery. |
| Bps | Bytes per second. |
| brb | Chat shorthand for "be right back". |
| bridge | A bridge is a combination of hardware and software that connects local area networks (LANs) of similar types together. See router. |
| brinking | Testing rules by getting as close as possible to breaking them without stepping over the line. A technique frequently used by trolls to stir up trouble in a discussion. |
| broadband | When the bandwidth of a signal is large, it can simultaneously carry many channels of information. Fiber optic cable, in particular, has a very high bandwidth, and is referred to as broadband. |
| browser | Software that will load and display a web page. A browser interprets the HTML or XML code from the web page files, executes embedded scripts and programs, provides encryption/decryption for security where needed, displays graphics (except text-only browsers), plays music and video, and provides links to related pages. Browsers are purportedly based on standards developed by the World Wide Web Consortium and recognized by the Internet Engineering Task Force. The major browser software developers participate in these organizations, but each of them also builds in their own proprietary codes, whether or not approved by the organizations. These differences in browsers create a challenge for web page developers. |
| btdt | Chat slang for "Been there, done that". |
| btw | Chat shorthand for "by the way". |
| bus | An electronic pathway. In networks, a configuration (topology) with a single linear cable, terminated at each end, to which computers and devices are connected. There are no loops or branches in the cable. Also called a daisy chain. |
| byte | 8 bits of data. Capital B is used in abbreviations to distinguish it from bits. For example, KBps (thousand bytes per second) is 8 times as great as Kbps (thousand bits per second). |
| cache | Browsers such as Netscape and Microsoft Internet Explorer hold copies of recently visited web files, both HTML and binary files, in disk memory. This disk memory space is called the cache. It offers the advantage of much quicker loading when files are stored on disk than when they must be transferred from the web. The disadvantage is that it will sometimes show you an old version of a file from your disk when a newer one is available on the web. Some large Internet service providers also cache frequently visited sites and feed them to you from their own cache when you try to visit them.
|
| Cascading Style Sheets (CSS) | Cascading Style Sheets is a technique built into version 4.0 and later browsers that support styles for pages. For example, you can set up styles for fonts and page layouts that will apply automatically to pages developed under a particular style you develop. This technique is useful, but the present version browsers from Netscape and Microsoft are quite different in their implementation, and what works with one is not likely to work for the other. For compatibility, care has to be taken to use common elements.
|
| case sensitive | When matching a string of letters, it is case sensitive if capital and lower case letters must match exactly. If an operating system or a piece of software is case sensitive, it will see all of the following text strings as different:
|
| CDSL | Acronym for Consumer Digital Subscriber Line. Rockwell's new technology for digital modems that will use regular telephone lines and run at speeds up to 1 MBps. See ADSL and DSL.
|
| censorship | Issues frequently arise online about censorship. When does a service provider or a mail discussion list host or a message base host have a right to delete material others have posted?
|
| CERN | the European Organization for Nuclear Research where the web was born. See Internet History. The original name in French was Conseil Europ�en pour la Recherche Nucl�aire (CERN).
|
| CGI | Common Gateway Interface. A method used by WWW pages to communicate with programs run on the web server.
|
| chain letter | A form of spam which asks you to distribute the letter to many other people. They are against the policies of most Internet service providers, and almost always are hoaxes. Many of them promise quick ways to make money, usually on the basis of pyramid or Ponzi schemes, which are illegal. Some make pie-in-the-sky promises, for example, that Bill Gates will give everyone $1000 for just helping test his new mail distribution scheme. Many of them prey on your sympathy and tell stories of a sick child who has asked that word be spread about the illness by chain letters. They may involve the Make-a-Wish Foundation, which states that they support no chain letters. Many report a virus warning, and ask you tell everyone about it. The virus warnings are invariably hoaxes. None of these purposes are legitimate. If you have any doubt at all about the legitimacy of a chain letter, please check the Department of Energy's Computer Incident Advisory Committee (CIAC) Chain Letter Page or ask us in the Navigating the Net Forum, and we'll research it and find the answers.
|
| charset | Short for character set. Different character sets are used for different purposes such as the different characters used by different languages.
|
| chat | A form of real-time electronic communications where participants type what they want to say, and it is repeated on the screens of all other participants in the same chat. Internet Relay Chat or IRC is an Internet protocol for chat, and there are many other chat systems in services like Delphi. Other commonly used chat systems are iChat and ICQ.
|
| churn | Rate of change, usually high; instability caused by frequent unplanned and hard to control changes. The word evolved from its use to mean agitation in such devices as butter churns and ice cream churns. In researching the term, I found modern examples of uses of the term to refer to changes in a customer base for wireless telephone, changes in routing patterns between ISPs, changes in membership of an e-mail discussion list, changes in click-through rates in web ads, rates of change in web pages, and prolonged hard disk activity.
|
| CIDR | Classless Inter-Domain Routing. This is a change in specifying ranges of IP addresses from the old Class A, B, and C address blocks. IP addresses consist of 32 bits, usually expressed in four 8-bit numbers, such as 122.63.101.17. In the old system, Class C specified 24 bits (the first three numbers in the conventional IP address), leaving all the addresses in the remaining 8 bits to be assigned by the registrant (256 addresses, less a few broadcast only addresses). Class B specified 16 bits and class A, 8 bits, leaving the balance to the registrant. Now, the IP address is followed by an IP Prefix, such as 122.63.101.14/26. The /26 IP Prefix means that the first 26 bits of the given IP address are fixed, and the registrant has the remaining 6 bits (64 addresses) to use and assign. IP Prefixes are currently used ranging from /27 (25 or 32 addresses) to /13 (219 or 524,288 addresses.
|
| CLEC | Competitive Local Exchange Carrier. See LEC.
|
| client | An individual computer on a network that runs its own programs and processes information received from a central server.
|
| client-server architecture | In client-server architecture, the computing load is distributed among the many clients (individual computers) in a network, drawing information from central servers of the information. On the Internet, a web browser is a client that runs software locally that processes information received from central servers of the information. The opposite of client server architecture is the situation where a central powerful computer does all the processing, feeding the results to dumb terminals which do little more than communicate requests and feed back the results processed centrally.
|
| coax, coaxial cable | A type of cable which contains two conductors, one inside and the other outside around it, separated by an insulating layer. They share the same axis, giving the cable its name co-axial. It is the same kind of cable that brings cable TV into your house.
|
| compression | Compression is a technique to make a file or a data stream smaller for faster transmission or to take up less storage space. There a number of programs that will compress files, such as PKZIP, WinZip, Stuffit, gnu zip, and many more. Files with the following extensions are almost always compressed files: arc, arj, gz, lha, lhz, taZ, taz, tgz, Z, zip, and zoo. See archive, second definition.
|
| content | Generally, the information provided on a web page, as opposed to its design and layout. Content can take the form of text, graphics, audio, video, or a searchable database.
|
| cookie | A cookie is a short file put on your system by a web page which includes information about your usage and facilitates the current interaction. For example, it may include the information that you have logged into a passworded area already in the current session and don't need a second password check.
|
| copy-and-paste, cut-and-paste | The technique of copying text from one location or file to another. If the text in the original location is deleted, it is called cut-and-paste. Whether cutting or copying, the process begins by positioning the cursor at one end of the text to be copied, and clicking and dragging to the other end to highlight the text. Or if you want to copy the entire text on a page, use Edit/Select All or press Control and the letter A simultaneously.
|
| copyright | The legal protection against copying and the specific rights allowing copying given to original works, which may be in printed or photographically or electronically stored words, music, visual arts, and performing arts. The purpose of copyright is not just to protect the rights, but to establish the rules under which copies or portions may be made to make a work more widely available. Copyright extends to electronic representations of these forms, too, although the laws governing new electronic copies in such forms as search engine indexes and browser caches needs better definition. Copyright exists on all original works from the moment they are published, whether formally registered or not and whether or not copyright markings appear on the works. Copyrights probably apply to public postings in e-mail, message bases, and newsgroups, but the law is not well tested in these areas. Copyrights are observed by most countries in the world.
|
| country code | Most countries in the world that are connected to the Internet have been assigned two-letter country codes by the international standard ISO 3166. These two letter codes are the major domain addresses for the country. For a complete list of them, see our Country Code List.
|
| cracker | A person who attempts to break into a network or computer system, often with the intent to steal material or perform malicious destruction of files--or just to show it can be done. See hacker, second definition. Crackers try to exploit weaknesses in system security or in some cases, the weaknesses of its users who can be tricked into revealing passwords. See social engineering.
|
| cram, cramming | Cramming is the practice by some phone companies, yours or others, to add false charges to your phone bills for calls you never made.
|
| crawler | See spider.
|
| CRC | Acronym for Cyclic Redundancy Check, a technique of providing a data string added to packets of information that can be used to detect errors in the data packets. In the OSI or TCP/IP network models, CRC is added to a packet frame at the Data Link Layer.
|
| CSS | See Cascading Style Sheets.
|
| cul | Chat shorthand for "see you later".
|
| cyberspace | A term coined by author William Gibson in his novel Neuromancer. It represents the totality of all connected computer networks and their contents in a future world. It has become a slang term for the Internet and the information in it.
|
| cybersquatting | The act of registering a company name as a domain name by someone outside the company in hopes of selling it to the company for a profit. Anti-cybersquatting legislation has been introduced to make it illegal.
|
| database | A collection of data records. On web databases, records may consist of web pages, or graphics, or audio files, or newspaper files, or books, or movies, or press releases, or almost anything from very general to very specific areas of interest. Records may or may not be further broken into fields. Database records are usually indexed and come with a search interface to find records of interest. See search engines. |
| datagram | In TCP/IP networks, datagram is a synonym for packet. |
| differentiated services | At present, all packets on the Internet are treated alike, regardless of their importance. If you want an important message to be delivered immediately or a streaming video signal to be distributed smoothly and without interruptions, there is no way to differentiate between immediate needs and routine transmissions which could be delayed for a long time without any problems. There are currently efforts under way to test and develop standards for differentiated services, where high priority data can be sent through or around clogged nodes ahead of low priority data. The high priority data transmission will cost more, of course. See ATM. |
| dither | To simulate a color that is not part of the current palette on-screen (or in print) by combining pixels of different colors close to each other. Viewed from a distance, it gives the effect of the color. Viewed closely, the dots are visible. Dithering can give a noisy appearance to a picture on-screen, but it often can be avoided by selecting non-dithering colors that are compatible with different browsers and platforms. See RGB and Creating Small, Fast-Loading Graphics for Web Pages for more help with this. |
| Digital Nervous System (DNS) | A term used by Bill Gates in frequent speeches in 1997 and 2000. Gates describes a future merging of PCs and communications in a wireless networked environment that makes it easy for people to navigate and share information. He speaks of a wireless pocket tablet ("a computer in every pocket") that enhances communications from many sources, aids in pattern recognition, and largely replaces telephone calls and paper messages and forms in business. |
| DjVu | Pronounced "deja vu". It is a compressed graphics format for showing scanned pages on the web. It does for scanned pages what PDF format does for electronically created documents. It requires a plug-in from AT&T. It uses a combination of compression formats that handles sharp-edged text one way and photographs and color blends another way, thus giving better compression than GIF, JPEG, or PNG can do. The server the document is placed on must be set for the MIME types x-djvu, djvu, and djv. For more information, see the AT&T DjVu FAQ. |
| Domain Name System (DNS) | Domain Name System. DNS servers are located at many strategic places on the nets to resolve the routing of e-mail and Internet connections. There are thirteen major, top-level DNS servers, which are updated daily, and these in turn feed the updated DNS information to smaller subordinate DNS servers, which hold more detailed information on their specific areas of coverage. No single DNS server has all the address information of the Internet, and successful routing may require routing through several levels of servers. |
| domain name | Domain name addresses, together with IP |
| dOoDz | Pronounced "dudes." Immature scofflaws. See wareZ |
| DOS (See also DoS, which follows) | Acronym for Disk Operating System. Literally, the term refers that portion of an operating system that controls writing, storage, and retrieval of data from storage media, usually spinning disks of various types. In common usage, the term refers to MS DOS, the |
| DoS (See also DOS, preceeding) | Acronym of Denial of Service, a form of assault on an Internet site which floods the site with packets requiring a response, thus slowing down or preventing normal access to the site. |
| download | To transfer a file from another system to your own computer system via a modem over telephone or cable lines or a telnet connection using a transfer protocol like xmodem, ymodem, zmodem, or Kermit. Less precisely, it may also refer to a direct transfer from a server to your local terminal over a local area network or an FTP transfer from a remote system to your system. See upload. |
| DQYDJ | Chat slang shorthand for "Don't quit your day job!" |
| DSL | Acronym for Digital Subscriber Line or Digital Subscriber Loop, often referred to as xDSL. It refers to several new digital technologies for fast two-way data connections over ordinary telephone lines. Rockwell announced a new Consumer DSL or CDSL technology in October 1997, which offers speeds up to 1MBps. US West introduced RADSL. The other technologies offer speeds up to 8 times as fast as that, but require more complicated installation. Rolloout has been slow, but it is spreading rapidly now. See ADSL. |
| DTD | Acronym for Document Type Definition or optionally Document Type Declaration, used in SGML and XML markup languages to specify the set of rules or grammar processed in a particular language. HTML versions each have their own DTD, for example. |
| Dublin Core | A proposed set of standard descriptive metadata elements used with web resources to aid in resource discovery. The elements are intended as a starting point for resource description. The elements are optional, and are intended to be extensible to richer descriptive elements when needed. The 15 elements are: |
| Dynamic HTML (DHTML) | A more powerful model for HTML that allows absolute control of positioning of elements on a page and more powerful control of events. It is supported by MSIE 4.0 and partially by Netscape 4.0. |
| e- (prefix) | A prefix meaning electronic for current jargon terms, such as e-commerce, e-business, and so on. |
| Easter egg | A hidden, undocumented program sequence built into a program that only activates when you press the right keys. They are often funny, and they are often used to introduce the team that developed the program. If you are using Netscape, typing about:mozilla into the URL window will give you an example. For many more examples, see C|Net's Easter egg page. |
| e-mail | Electronic mail. One of the earliest standard Internet protocols which enables people with different computers and operating systems to communicate with each other. E-mail allows one-to-one or one-to-many mailings. Mail is received and held by a mail server within an organization or by an Internet service provider until the addressee logs on to collect the mail. The Internet e-mail standards include no provision for authenticating the sender, which makes it possible for spammers to use false From addresses and routing. See the E-mail FAQ. |
| emoticon | See smiley face. |
| ethernet | A LAN protocol developed by DEC, Intel, and Xerox as an outgrowth of Harvard graduate student Bob Metcalfe's dissertation on packet networks. Computers using TCP/IP often connect to the Internet via ethernet LANs. Ethernet typically uses a bus (daisy chain) topology. |
| extranet | A network that supplements a closed intranet by providing access to customers, suppliers, subcontractors, and others outside the organization who have a need for selective information from the organization. It is not accessible to the Internet at large. |
| fair use | Fair use is the concept in copyright law that some limited copying of copyrighted material is permissible in certain circumstances. A complete work may never be copied. The broadest permissions are for educational purposes, such as copying an article from a magazine or a chapter from a book for a class to use. Other more restrictive permitted uses are short excerpts for purposes of news reporting, criticism, and parody. See our Copyright Guidelines for Web Users. |
| FAQ | Acronym for Frequently Asked Questions. FAQ files are collections of common questions and answers for a particular subject area. For example, see the Navigating the Net FAQ for general Internet and World Wide Web questions and answers and the Publishing on the Web FAQ for questions and answers on creating web pages. For many more FAQs, visit the Usenet FAQ Archive at Ohio State |
| firewall | Firewall refers to the concept of a security interface or gateway between a closed system or network and the outside Internet that blocks or manages communications in and out of the system. The security may be provided by passwords, authentication techniques, software, and hardware. See the related term proxy server. |
| flame | To write angry or insulting words about a person. It is most often applied to newsgroups, but it can apply to mailing lists, message boards, and other forms of public messaging. |
| flame war | When two or more people exchange insults in a public messaging. It is sometimes done deliberately to disrupt the normal flow of messages. See troll. |
| frames | Frames are a technique used in web pages to divide the page into multiple windows, where each window is called a frame and can contain its own separate page. The advantage of frames is that one window can be scrolled or changed while other windows remain fixed for such purposes as keeping a menu in view all the time. The disadvantage is that not all browsers support them. |
| frame relay | A packet switching standard based on the older X.25 protocol that achieves greater speeds with fast, reliable networks. It lowers overhead by reducing the accounting and checking procedures used in X.25. |
| freeware | Software that is offered for free download. See shareware. |
| FTP | File Transfer Protocol. The Internet protocol that permits you to transfer files between your system and another system. You can use its command language from a shell account or various programs with SLIP or PPP accounts that simplify the process. See the FTP FAQ |
| FUD | Acronym: Fear, Uncertainty, and Doubt. A common motivational strategy. |
| FWIW | Acronym for "For What It's Worth" |
| GMT | Greenwich Mean Time, often used as a standard time zone. In e-mail headers, you will often see references to the hours offset from GMT. For example, Eastern Standard Time is GMT minus 5 hours because of the 5 hour difference between Greenwich, England and the Eastern US. |
| gmta | Chat shorthand for "great minds think alike". |
| gopher | A friendly menu system for exploring the Internet developed at the |
| GPF | General Protection Fault. The curse of Windows! See our GPF Guide, How to Avoid GPF's While Browsing the Nets. |
| grep | A unix search command that will search for matching text or a "regular experession" ( regexp) in a file. It derives from the intial characters of Global Regular Expression Print. |
| griefer | An online game role player who sabotages the game by harassing, deceiving, cheating, robbing or killing newer players. |
| GUI | Graphical User Interface. Pronounced "gooey". An operating system interace between the user and the computer based on graphics. GUIs typically use a mouse or other tracking device and icons. First developed by XEROX as an easier to learn interface than text-based ones, it was adopted by Apple for the Macintosh, Microsoft for Windows, and even for unix systems as XWindows. |
| GUID | Globally Unique Identifier. A controversial 16-byte number generated by Microsoft programs that uniquely identifies a network or user or computer or document. It is one of the elements of information that can be passed when you connect to an Internet site, and it may be stored in cookies. |
| 1-tier architecture | A simple form of standalone application architecture where everything resides in a single program. Contrast this to 2-tier and 3-tier architectures. |
| Hertz, Hz | Cycles per second. Used to describe the cycle rate in radio, electronics, and audio. Abbreviated Hz, and often combined with numeric prefixes, such KHz, MHz, GHz, and so on. Named for the German physicist Heinrich Hertz, who discovered electromagnetic waves. |
| hex, hexadecimal | Base 16 arithmetic. Conventionally, the 16 digits are represented by the digits 0 through 9 and the letters A through F. The letter A, for example, represents the decimal number 10. A byte (8 bits of data) is often represented by two hexadecimal numbers. The hexadecimal values can range from 00 to FF or from decimal 0 to 255. Hexadecimal values are often differentiated from decimal by either following them with the letter h or preceding them with an angle bracket, for example 33h or >0B. Hexadecimal numbers have many applications in computer programming, and they are frequently used in RGB (red/green/blue) color coding for web pages. |
| hoax | There are many hoaxes continually popping up on the nets. False viruses are the most common of these with names like "Join the Crew" or "PenPal Greetings", but there are many more themes that keep recurring. Appeals to charity is a common theme for a hoax, sometimes partially based in fact. If you get a chain letter appeal about Jessica Mydek or Craig Shergold or anything involving the Make A Wish Foundation, please check it out first before spreading it. |
| home page | A home page is a web page. In most familiar terms, it is a personal page for an individual. It can also be the basic main page for a more complex web site for individuals, organizations, or web communities. On complex web sites, it is the page which a server will show when no HTML filename is listed, usually with the name index.html, home.html, or default.html or the same names with the shorter extension .htm. |
| HTML | HyperText Markup Language. The coding system used to create WWW pages. A page written in HTML is a text file that includes tags in angle brackets that control the fonts and type sizes, insertion of graphics, layout of tables and frames, paragraphing, calls to short runnable programs, and hypertext links to other pages. Files written in HTML generally use an .html or .htm extension. See the World Wide Web Consortium (W3C) HTML Page for more information. |
| http | HyperText Transfer Protocol. It is the main protocol used on the World Wide Web that enables linking to other web sites. Addressing to other web pages begins with "http://" and is followed by the domain name or IP address. See URL. |
| hub | A device that connects the cables from computers and other devices such as printers in an ethernet local area network. Traditionally, hubs are used for star topology networks, but they are often used with other configurations to make it easy to add and remove computers without bringing down the network. Smart hubs or switching hubs are often used to improve performance by managing traffic. |
| hyperlink | A link in a web page that brings you to another location or resource when activated. Hyperlinks usually appear as underlined text and printed in a contrasting color, but they may also appear as graphics, such as buttons to click. Hyperlinks may link to another place in the same page, to a different page, to play an audio or video file, to download a file, to set up a message to an e-mail address, to search a database, to read Usenet newsgroups, and to link to other Internet resources. |
| hypermedia | Like hypertext, but includes other interlinking media, such as graphics, audio, video, and VRML. |
| hypertext | A form of text which includes visible links to other pages of text or media, accessible by clicking or selecting the links. |
| IANA | Internet Assigned Numbers Authority |
| ICANN | Internet Corporation for Assigned Names and Numbers |
| IEEE | Institute for Electrical and Electronics Engineers, a professional organization which sets standards for telecommunications and computers. |
| IIRC | Short for If I Remember Correctly. |
| ILEC | Incumbent Local Exchange Carrier. See LEC |
| image map | A graphic on a web page used for navigation. Clicking on different representative areas of the graphic links you to different related pages. Web designers should always consider alternate menus for image maps or else those without graphical browsers are unable to proceed. |
| IMAP | Internet Message Access Protocol (sometimes listed as Internet Mail Access Protocol). A mail protocol that provides management of received messages on a remote server. The user can review headers, create or delete folders/mailboxes and messages, and search contents remotely without downloading. It includes more functions than the similar POP protocol |
| IMHO | Shorthand for In My Humble Opinion. Often used in chat and messages by people whose opinion is anything but humble. Sometimes more accurately rendered as IMNSHO (In My Not So Humble Opinion). |
| inlining | The practice of putting an IMG tag in a web page that calls a graphic from another site. Many sites, particularly those offering free storage, now view this as bandwidth theft and block remote IMG calls from other sites to their site. It is particularly bad netiquette and very likely a copyright violation to display a graphic called from someone else's web page. |
| intellectual property | The concept of legal protection for original creations. It encompasses copyright, trademarks, and patents. |
| Internet | 1. A network of many networks that interconnect worldwide and use the Internet Protocol (IP). See the Internet FAQ. |
| Intranet | A network of networks that interconnects within a single widespread organization and uses the Internet Protocol (IP). The sites within an Intranet are generally closed to the Internet and are accessible to organization members only. See extranet. |
| IP | Internet Protocol. See TCP/IP |
| IP address | IP addresses, together with domain addresses are |
| IRC | Internet Relay Chat. An Internet protocol that allows people all over the world to meet in |
| ISDN | Integrated Services Digital Network. A technology that carries data over phone lines at up to 128Kbps for dialup users, but extends to fast broadband communications, too. It applies to the first three layers of the OSI and TCP/IP models. Slow to get started in the US, it is likely to be overtaken by the much faster DSL models over the next few years. |
| ISP | Internet Service Provider. To find one, try ISP Deals. |
| IXC | Inter eXchange Carrier. Another name for a long distance telephone company. See LEC. |
| Java | A programming language developed by Sun Microsystems based on C++. It is used with web pages to create applets that will run on different platforms. |
| JavaScript | A script language (with little in common with Java) developed by Netscape for writing short programs embedded in a web page. It is supported by Netscape from version 2.0 on and Microsoft and AOL browsers from version 4.0 on. MSIE 3.0 partially supports some features of JavaScript. See Recommended Books on JavaScript. |
| JPEG | Joint Photographic Experts Group, a graphical format that is widely used in WWW pages. |
| JUGHEAD | Searchable index software that can be applied to a an organization's gopher menus similar to VERONICA. It supposedly was named for its inventor, Rhett Jones, as Jonzy's Universal Gopher Hierarchy Excavation And Display. But since the search tools archie and VERONICA came before it, the name obviously preceded the acronym. See archie and VERONICA. |
| KBps | kilobytes per second |
| Kermit | A common terminal emulation program and file transfer protocol that can be used across dialup and telnet connections. It is much slower than xmodem, ymodem, and zmodem in most implementations, but it has the advantage of being able to transfer 8-bit files across a 7-bit telnet connection, which the others will not do. It was developed at Columbia U and is widely used in academia, probably because it is free. It was named for the frog. |
| lamer, lammer | A derogatory term for a wanna-be programmer or hacker or cracker who is clueless, often destructive, and not as expert as he thinks he is. A 'luser'. |
| LAN | Local Area Network. |
| LDAP | Acronym for Lightweight Directory Access Protocol. It is a protocol for accessing information directories such as organizations, individuals, phone numbers, and addresses. It is based on the X.500 directory protocols, but it is simpler, and unlike X.500, it supports TCP/IP for Internet usage. The standards are specified in RFC 1777. |
| LEC | Local Exchange Carrier. The local telephone company serving an area. There are Incumbent LECs (ILEC)--those with a local monopoly--and Competitive LECs (CLEC). Long distance companies, also known as IXCs (Inter Exchange Carriers), pay LECs a fee for access to local telephones. |
| leet | Short for elite. Jargon used by hackers and crackers to refer to themselves or to the sites they frequent to share pirated software and information. |
| link | An active connection to another web page, location in a web page, file, or other Internet resource. Selecting the link takes you to the new location or resource. See URL. |
| linux | A version of unix well adapted to running on personal computers. For more information, visit the Delphi Unix Forum. |
| listserv | One of the earliest types of e-mail discussion lists, and still in widespread use, although |
| listproc | One of the common types of E-mail discussion lists. See our E-Mail Discussion List FAQ and our Guide to Subscribing, Unsubscribing, and Searching Mailing Lists. |
| LOL | Acronym for Laughing Out Loud. |
| lossy | A term coined by graphics programmers to refer to a technique of shrinking file sizes by giving away some precision of detail. JPEG is the most common of these. By reducing the so-called quality of a picture when you save it, you can make the file size smaller. Many pictures can take a lot of loss of fine detail before it becomes noticeable on a web page. |
| lurk | Listening in to a mailing list, message base, chat room, or newsgroup without participating. Newcomers are encouraged to lurk for a while as they |
| luser | A user who is a loser. The result of a dispute at MIT some years ago where computer error messages referred to errors by users. Others changed users to losers, and the dispute continued until someone coined the term lusers, which everyone liked. |
| Lynx | A text-only web browser that was an early workhorse before the web gained its graphical face. It is still used extensively today by the visually impaired, people with limited systems, and those with slow connections who don't want to take the time to load graphics. |
| macro virus | A virus contained in and spread by a macro language program that supplements a word processed document or spread sheet. These are by far the most common type of viruses now, and they can easily be spread in attachments to e-mail. Never open an e-mail attachment without running anti-virus software first. If you need recommendations for good anti-virus software, ask in the Navigating the Net Message Board |
| MAE | Metropolitan Area Exchange or Metropolitan Area Ethernet. A major Internet Network Access Point (NAP) where different providers and networks hand off traffic to each other. The two main MAEs in the United States are MAE East in Washington, DC and MAE West in Silicon Valley. |
| mailbomb | Flood a single e-mail address with a high volume of mail. Used to retaliate against an individual or organization that has bothered the sender(s) in some way. Please note that the practice violates all ISP user agreements and wastes bandwidth and resources. Its effects go far beyond the annoyance to the addressee. Don't try it! |
| majordomo | One of the common types of E-mail discussion lists. See our E-Mailing Discussion List FAQ and our Guide to Subscribing, Unsubscribing, and Searching Mailing Lists. |
| MAPI | Acronym for Message Application Programming Interface. A standard Windows interface for messaging that enables different mail programs and other mail-aware applications like word processors and spreadsheets to exchange messages and attachments with each other. |
| MBps | Abbreviation for megabytes per second. |
| mega | Prefix meaning one million (106) or in computer usage, the similar value 1,048,576 |
| meta | A prefix meaning "information about". |
| metadata | Information about data, or more specifically, the descriptive information provided in meta tags in an HTML or XML document header about that document. |
| metafile | A graphics format that combines the features of bitmap and vector graphics. Common types of metafile formats are CGM, Corel Draw CDR files, encapsulated Postscript EPS files, Adobe Illustrator, Word Perfect Graphics WPG files, PICT, and RTF. |
| meta tag | In HTML or XML, a tag used in the header of a page to provide information about the page. There may be multiple meta tags in a header, each with different information. In current usage, each tag includes the name of the information and the content that supports that name. As an example, here is an author meta tag: |
| MIDI | Musical Instrument Digital Interface. See the Audio Guide and the File Extension Guide for more information. |
| millenium bug | The set of problems occurring on January 1, 2000 and other related dates caused by shortsighted programming that coded the years with only 2 digits. Ambiguity arises in the year 2000 as to whether 00 represents the year 1900 or the year 2000, and calculations based on it may fail or produce incorrect results. It can affect software, hardware, operating systems, and devices with embedded software. Another common programming error is failing to account for the year 2000 as a leap year (by the 400 year rule). |
| MIME | Acronym for Multipurpose Internet Mail Extensions. The standard for |
| modem | Short for modulator/demodulator. A modem is used between a computer and a phone or cable line to convert the computer's digital signal to an analog signal for the line and vice versa. |
| MOO | MUD, Object-Oriented. See MUD. |
| Mosaic | The breakthrough first graphical browser, developed by Marc Andreeson and others at the National Center for Supercomputing Applications (NCSA) at the University of Illinois at Urbana Champaign. Andreeson graduated and went on to found Netscape and the Netscape browser. |
| MUD | Acronym for Multi-User Domain, Multi-User Dimension, or Multi-User Dungeon. An online interactive computer game or exploration medium. Early MUDs were Dungeons & Dragons-like games in text-only forms, but they have grown into many other forms, too. They are now used for social gatherings, interactive learning, chat rooms, and much more, as well as the old-style entertaining games. Originally accessible only through telnet, many of them have migrated to the web, and even appeared in graphical virtual reality and 3D forms. Variations are known as MUSHes, MUSEs, and MOOs. For specific examples, see Delphi's selective DRAGONet Multi-User page and for more links, see Yahoo's list of links to MUDs, MUSHes, MOOs, etc. Good gaming! |
| NAP | Network Access Point. A point where networks and service providers hand off traffic to each other. NAPs are typically the points with the worst congestion problems. When you encounter slow responses and run a traceroute, you will usually see the slowest connections occur where one network hands off to another. See MAE. |
| netiquette | Short for net etiquette. The basic principles of courtesy and |
| newbie or newby | A newcomer to the nets, who reveals his or her inexperience by lack of knowledge of net conventions, netiquette, vocabulary, and know-how. |
| newsgroup | See Usenet newsgroups |
| NIC | Acronym for Network Interface Card, for example, an ethernet card in a network. |
| NSFNet | National Science Foundation Network. The National Science Foundation followed on the earlier ARPANet by creating NSFNet in 1986 as a 56 Kbps backbone for the Internet. Commercialization of the nets began in 1992. By 1995, the National Science Foundation withdrew its sponsorship and concentrated on funding research for newer, higher speed initiatives. |
| nslookup | A common Internet utility like ping and traceroute. Given an IP address or a DNS address, it will look up and show the corresponding DNS or IP address. There are nslookup utility programs available for every operating system, which you can use with a PPP or networked or shell account. The commonly used FTP program WS_FTP Pro includes a number of utilities including nslookup. |
| OLR | OffLine Reader. Software which will collect messages for you from mail, newsgroups, and message bases, send new ones you have written, and let you read and respond offline. |
| OSI | Acronym for Open Systems Interconnect. This is a model for connecting computers together in a network. The model consists of seven distinct and separate layers of protocols. |
| OTOH | Acronym for On The Other Hand often used in chat. |
| packet | A packet is a self-contained bundle of data sent over a packet switching network. Packets are typically less than 1500 bytes in size. Longer files are broken into multiple packets for transmission and reassembled at the other end. A packet includes a header with to and from addresses, relation to other packets (sequencing), and error checking information. On the Internet, datagram is a synonym for packet. See TCP/IP. |
| palette | The set of colors used in a picture or on a computer screen. Older computers typically used only 16 colors. Modern ones use at least 256 colors, which can be coded by 8 bits of information. With advanced color cards and monitors 65.5 thousand colors (16-bit) or 16 million colors (24-bit) are used. Different web browsers and computer platforms do not necessarily use identical palettes. There is a set of 216 colors that are considered browser and platform safe, which web page designers should use, if they want screens to look essentially the same on each computer that views them. See Web Safe GIF Colors, Dithering, and Anti-Aliasing for more help with this. |
| PDF | Adobe's Portable Document Format. It is often used as a format which allows much more complete, controlled layout of a page and its graphics and text than conventional HTML does. It requires a browser plug-in to see a web page in PDF format. Files will usually have a .pdf extension. |
| PGP | Pretty Good Privacy, Phil Zimmerman's pioneering encryption software that successfully defied government restrictions and won him many awards. PGP is now available from PGP Corporation. |
| PICS | Acronym for Platform for Internet Content Selection, a model for associating labels with content in header metadata, originally devised to help parents and teachers and filtering software control children's access to the net. See the World Wide Web Consortium (W3C) PICS Page for further information. |
| PING | Packet InterNet Groper. An Internet utility used to check the connection with another site. It repeatedly bounces a signal off the remote site and shows you how long it took to complete the round trip each time. If you get no returns at all, the site is either down or unreachable. If only a portion of the signals are returned, it indicates some trouble with the connection that will slow down performance. You can run PING software on your own system with a PPP or net account, or you can use it as a command from Delphi's NavNet textside Utilities menu and from most shell accounts. See traceroute. |
| pixel | One dot on a computer screen. Todays least expensive monitors typically are 640 pixels wide and 480 pixels high. Larger and more expensive monitors range up to 1600 x 1200 pixels and special purpose monitors may go much higher than that. |
| plonk | Usenet speak for "You're in my kill file, bozo!" Supposedly the sound of a newbie falling to the bottom of a kill file. See bozo filter. |
| plug-in | A piece of software that plugs into a main program to give it added capability, for example, you can add a Quick Time plug-in to your browser to play Quick Time movies on the web. |
| PMFJIH | Shorthand for Pardon Me For Jumping In Here. Often used in chat and messages as a polite excuse to enter the discussion. |
| POP | Post Office Protocol. A protocol for client-server e-mail systems. If you are using software like Eudora or Pegasus or the mail clients in Netscape or |
| portal | A gateway or entrance to the web. In common usage it has come to describe a starting point page with a hierarchical, topical directory, a search window, and added features like news headlines and stock quotes. For typical examples, see Yahoo and Netscape Netcenter. |
| POTS | Acronym for Plain Old Telephone Service. |
| PPP | Point to Point Protocol. Along with the older SLIP, a protocol that is |
| PPTP | Point to Point Tunneling Protocol. A new technology developed by Microsoft, US Robotics, and others to enable Virtual Private Networks (VPN) to work securely over the Internet without exposing their communications to intercept. It is currently available only to Windows NT and linux networks. As of June 2, 1998, security flaws have been revealed in Windows NT, which make it much less secure than previously believed. Security patches are expected. |
| privacy | A source of concern to many on the Internet is how much personal information on them is available to all who look for it. Wherever you open an account on the Internet and World Wide Web, you are asked for personal information. What happens to this information? Do you have a rignt to privacy? See our article on Privacy: What Can Others Learn About You?. See also, Delphi's Privacy Policy |
| protocol | A standard for the exchange of information. Different computers and operating systems and software are able to communicate with each other on the Internet, because of the adoption of protocols. |
| proxy server | A proxy server is a process that acts like a switchboard through a firewall to manage the various types of permitted communications with the outside world. Proxy servers may also use caching to make communications more efficient. |
| push | The technology that puts pre-selected content directly on your computer screen from the Internet without your need to browse for it. With this technology, introduced by PointCast and Individual, Inc.and added to 4th generation browsers, you can program your desktop, for example, to automatically receive such things as local weather, news headlines, selected stock reports, and sports scores for selected teams or events. |
| queue | A backup of packets or messages awaiting processing. |
| RADSL | Acronym for Rate Adaptive Digital Subscriber Line, currently being introduced by US West. See DSL. |
| RAID | Redundant Arrays of Independent Disks. Using duplicated disks for error recovery and more efficient operation. |
| RDF | Acronym for Resource Description Framework. A formal data model from the World Wide Web Consortium (W3C) for machine understandable metadata used to provide standard descriptions of web resources. It uses eXtensible Markup Language (XML). It is similar in intent to the Dublin Core, although perhaps broader in its scope and purpose. See the W3C RDF Page for further information. |
| re, re's | Chat shorthand for "rehi", meaning "hello again". |
| refresh | A meta tag that will let you either periodically refresh the current page or switch to another page. It is formatted like this: |
| reg exp | Unix term for "regular expression", a series of characters used in a search. The characters &, $, ^, , and square brackets are given special meanings in regular expressions. Here are some common examples: |
| reverse lookuup | A telephone directory service where, given the phone number, you can look up the name. |
| RGB | RGB is short for the colors red, green, and blue often used in color coding on web pages, particularly for GIF files. 64K color values can be represented by a byte (8 bits of data) each for red, green, and blue. These are commonly expressed in hexadecimal values from 00 too FF for each color. The color value for white in this system is FFFFFF, where each color is at maximum value. Red is FF0000. Yellow is FFFF00. There is a smaller set of non-dithering colors where the permissible values for each color are hexadecimal 00, 33, 66, 99, CC or FF or decimal 0, 51, 102, 153, 204, and 255 and the results will look the same with different browsers, computers, and color cards. See the article, Creating Small, Fast-Loading Graphics for Web Pages for a further explanation. |
| RJ-11 | The type of modular jack used with telephones. It connects one to three pairs of wires with a transparent connector that plugs into your phone on one end and a wall jack on the other. |
| RJ-45 | A modular jack that can connect up to four pairs of wires. It resembles the RJ-11 telephone jack, but is a bit larger. It is commonly used to connect twisted pairs of cable in a LAN. |
| rlogin | Remote login, a protocol similar to |
| ROFL, ROTFL, ROTFLMAO, ROTFLMAOSTC | Chat shorthand for Rolling On the Floor Laughing. Commonly used in chat or messages to signify mirth in response to another's comment. Often expanded to ROTFLMAO (...Laughing My Aft Off). The latest expansion (STC) is ...Scaring The Cat. There are many variants. |
| router | A router connects networks together, controlling the routing of packets from source to destination and providing alternate paths when necessary. Routers are more sophisticated than bridges, connecting networks of different types (for example, star and token ring), and making logical routing decisions on the basis of available data. Typically a router hands off packets to another router along the path until the destination is reached. See bridge. |
| rsn | Chat shorthand for "real soon now". It represents an indefinite period of time somewhat longer than the time "the check is in the mail." |
| rtf | Rich Text Format. A text format that allows a lot of specific formatting and layout. Uses the .rtf extension. |
| rtfm | Chat shorthand for "read the fine (or another four letter F word) manual". |
| SAN | Storage Area Network. A high speed network of shared storage devices. |
| search engine | A utility that will search the Internet, an Intranet, a site, or a database for terms that you select. Search engines on the web consist of four elements: |
| server | A computer in a network that provides access to other computers in the network to programs, web pages, data, or other files and services, such as printer access or communications access. A server may also authenticate requests for files and services before providing them. See also proxy server and client-server architecture. |
| SGML | Acronym for Standard Generalized Markup Language. It was adopted in 1986 as an international standard (ISO 8879) for the creation, management, storage, and delivery of information products. HTML and its possible successor, XML, are both subsets of SGML. See the SGML/XML Home Page for more information. |
| shareware | Software that is offered for free download in hopes that the user will decide to keep it and pay a fee for it after trying it out. See freeware. |
| shell, | An Internet account, usually unix based, that provides the Internet software for you. In contrast, SLIP, PPP, and ethernet accounts give you a connection where you run your own Internet software, such as browsers, gopher, telnet, e-mail, and so on. Shell accounts run these for you, and usually only provide text modes without graphics. Most shell accounts require some knowledge of unix commands, although many functions can be set up in friendly menu structures. A shell account can be based in VMS, as well, such as Delphi Internet Service's older textside access. |
| site | A host on the Internet which allows remote access by such protocols as http, ftp, telnet, or gopher. A site may consist of a single page or many pages under a common site name. Whether two addresses with a common site name are one site or more than one may vary depending on your point of view. For example, to some, all pages at the Internet Service Provider delphiforums.com might be considered one site. But an individual who has set up personal web pages at people.delphiforums.com will refer to his or her pages as |
| slam, slamming | Slamming is the practice of telephone companies shifting you to their long distance service without your permission or obtaining your permission deceptively. |
| SLIP | Serial Line Interface Protocol. Along with the newer PPP, a protocol that |
| smiley face | A happy face or other expression formed with typed characters, |
| SMTP | Simple Mail Transfer Protocol. The protocol used to send mail between servers and to send mail from your client to a mail server. Your address to |
| SNMP | Simple Network Management Protocol, a standard for managment of devices such as hubs, routers, and switches attached to an IP network. It operates at the application layer of the OSI Model. See SNMP.com for much more information. |
| social engineering | A cracker term for tricking users of a system to reveal passwords so that the cracker can gain entry to the system. A common technique is to contact users in chat or e-mail on a system, pretend that they are employees of the system performing security checks, and insist that the users give their password to prove who they are or their account will be closed. Such requests are never legitimate! Social engineering schemes can be quite ingenious and convincing and more subtle than the simple technique above. Never reveal a password or even give hints what it may be. |
| spam | Traditionally, spam is flooding message boards, newsgroups, mailing lists, or your mailbox with unwanted, unsolicited off-topic messages--usually ads or promotions or deliberate disruptions. It is a major violation of netiquette, and it violates member agreements in most places and can lead to account cancellation. While spam is usually viewed as large numbers of messages, to the individual, one unwanted message is spam. The term was inspired by an old Monty Python sketch about a repetitive menu with spam, spam, eggs, and spam. |
| spider | A software robot that serves a search engine by exploring the net, collecting web page addresses and page contents, and following links from them to other addresses to collect still more web information. Also known as a worm or crawler. See search engine. |
| spyware | Software planted on your system to capture and reveal information to someone outside your system. It can do such things as capture your keystrokes while typing passwords, read and track your e-mail, record what sites you visit, pass along credit card numbers and so on. It can be planted by Trojan horses or viruses, installed as part of freeware or shareware programs you download and run, installed by an employer to track your computer usage, or even planted by advertising agencies to assist in feeding you targeted ads. |
| SSL | Secure Sockets Layer. A security protocol developed by Netscape for commercial transactions on the Internet. Using public-key cryptography, it provides server authentication, data encryption, and data integrity. You can recognize its use with URLs beginning https instead of http. |
| star | A network configuration (topology) in which all computers and devices are connected by direct cables to a central hub. |
| stopword | Stopwords are very commonly used words that are normally excluded from automated searches. Examples: a, an, the, for, to, in, on, and, etc. |
| streaming audio, streaming video | Technologies which permit listening and watching continuously as the signal is transferred to your system from a remote web site. It requires a high degree of compression to transfer audio or video (or both) at 28.8 Kbps or 14.4 Kbps speeds and still retain quality music and non-jerky video. If stereo sound is desired, there is a trade-off in the sound quality. These technologies are continually improving and the sound and video sampling and compression techniques are getting better. Faster connection speeds are needed to improve quality substantially, and the speed must be maintained over the entire path between the transmitting and receiving systems. The systems generally use a few seconds buffering, but signal slowdowns or interruptions longer than that break the flow. |
| surf | To explore the nets without any more specific a purpose than to see what is out there. |
| SVG | Scalable Vector Graphics. A proposed format by the World Wide Web Consortium (W3C) for web page graphics based on vectors, rather than bitmap formats. These files will normally be smaller than bitmap files and will scale to different size screens. See the W3C Scalable Vector Graphics page. |
| Unicode | A standard character set which uses two bytes or 16 bits to code each character. Compare it to ASCII, which uses only one byte or 8 bits per character. ASCII is limited to 256 characters, enough for most European languages, but too limited for languages like Chinese and Japanese with their many characters. For more information, see the Unicode Home Page. |
| unix | A computer operating system widely used on computers big and small, and very commonly used on the Internet. Many of MSDOS' commands were adapted from the short, cryptic commands characteristic of unix, such as rm, cd, and mv. For more information, see the Unix FAQ and visit the Delphi Unix Forum. |
| upload | To transfer a file from your computer system to another system via a modem over telephone or cable lines or a telnet connection using a transfer protocol like xmodem, ymodem, zmodem, or Kermit. Less precisely, it may also refer to a direct transfer from your local terminal to a server over a local area network or an FTP transfer from your system to a remote system. See download. For help uploading HTML files and graphics to your web page, see the PubWeb FAQ. |
| urban legend | An oft-told tale on the Internet that is untrue, but refuses to die. They |
| URI | Universal Resource Identifier. A standardized method of identifying |
| URL | Uniform Resource Locator. URLs specify the location of a resource in |
| URN | Uniform Resource Name. A standardized name for a persistent, location-independent, resource identifier. As conceived, when the system is implemented, you will be able to link to a resource by URN without specifying its location. |
| Usenet Newsgroups | Usenet Newsgroups are discussion groups about a topic that is |
| vector graphics | In mathematics and physics, a vector is a line which has a defined starting point, a designated direction and a specified distance. Vector graphics are line-based graphics. In vector graphics, vectors determine how straight and curved lines (Beziers or splines) are shaped between specific points. The lines and the colors of areas enclosed by the lines make up the picture. Microsoft SYLK is an example of a pure vector format. More commonly used are bitmap files and hybrids of vector and bitmap known as metafiles. |
| VERONICA | The gopher-based search engine that worked with an index of gopher menus around the world. The last VERONICA search engine on the nets is probably gone for good, but before the web's spectacular growth, it was a real workhorse for searchers . It supposedly is an acronym for Very Easy Rodent-Oriented Netwide Index to Computerized Archives, but since the archie FTP search preceded it in time, the name pretty obviously came before the acronym. See archie and JUGHEAD. |
| Virtual Private Network (VPN) | A private network within a public network, usually on the Internet. Privacy for the virtual network is achieved through encryption and provides a less expensive option than using dedicated lines. See PPTP. |
| virtual reality | A computer simulation of a real 3-dimensional world, often supplemented by sound effects. One early example allowed you to drive through a city, turn at any street intersection, and see what you would see out of a car window. Another let you learn a ship's layout by moving throughout all of its decks. Modern games let you fly an airplane or spaceship in combat or explore a dungeon and kill its monsters. Educational applications let you learn through experience for many types of simulated tasks or interact with professors and class members at a distance. See VRML. |
| virus | A destructive program that has the ability to reproduce itself and infect other programs or disks. Typically a virus will not show itself immediately, but will add itself to programs and disks to spread itself widely on many computers before it is triggered into its destructive phase. The best defense is to run anti-virus software and use it on all new software and disks introduced to your system. Anti-virus software should be updated monthly. For authoritative current information on viruses, visit the Dept of Energy's Computer Incident Advisory Committee (CIAC) web site or the Symantec Anti-Virus Research Center. |
| vortal | A vertical portal. A apecialized portal that serves a particular organization or interest group, rather than trying to be all things to all people. |
| VPN | See Virtual Private Network. |
| VRML | Virtual Reality Modelling Language. A graphical system that creates views of 3-dimensional images that change as the viewer's angle and position changes and light sources change. It can be used to create an environment or world that appears realistic as you "move" through it. It is widely used for games and for educational applications. The technology is very young and growing fast. It requires a fast computer and fast video support with lots of memory to be effective. For a good starting point to learn about VRML, try Yahoo's VRML Page. |
| W3C | Abbreviation for the World Wide Web Consortium, the organization that develops standards for the web community. |
| WAIS | Wide Area Information Server (WAIS). An indexing system for |
| WAN | Wide Area Network. |
| WAP | Wireless Application Protocol. A protocol used with small handheld devices with small file sizes. |
| wareZ | Software pirated by dOoDz (immature scofflaws). |
| web site | One or more connected web pages under a common ownership or management or theme. |
| weblog | See blog |
| webtag | A term unique to Delphi Forums which designates a particular Forum on that service. Every Forum has its own webtag, different from all others, which forms part of the address for web pages, message boards, and chat rooms for that Forum. Addresses take these forms: |
| WEP | Wired Equivalent Privacy or less frequently, Wireless Encryption Protocol. A security protocol for wireless networks defined in the 802.11b standard. Being key-phrase based, it does not provide a high enough level of security for critical data that might be specifically targetted for its value, but is reasonable for home network security in most cases. |
| whois | An Internet utility that you can use to look up information about an Internet site in the registry database at Internic or elsewhere. You can enter a name like Delphi, a domain |
| wi-fi | Short for wireless fidelity, a standard for wireless ethernet. The term is synonymous with the IEEE 802.11b standard. |
| World Wide Web (WWW) | The World Wide Web is an Internet protocol that makes use of the HTML, hypertext, and hypermedia to create pages with links to other pages. WWW pages can include graphics, audio, and video as well as text. See the WWW FAQ and the Internet History for more information. |
| worm | A self-replicating program that reproduces itself over a network. The most famous worm is the one created by Robert Morris at Cornell that shut down many unix computers on the Internet in 1988. Currently making the rounds is a Windows worm named happy99.exe (or Trojan-Happy99 or I-Worm.Happy) that masquerades as a fireworks show, replaces your wsock32.dll file, and sends copies of itself along with e-mail or news messages you post. For more on this and how to remove it, see the Symantec Anti-Virus Research Center Happy99 Worm page. See virus and Trojan horse. |
| WPA | Wi-fi Protected Access. An interim security standard for wireless networks designed to be more secure than WEP. It is taken from the draft 802.11i standard. |
| WYSIWYG | Acronym for "What You See Is What You Get". The term applies to word processors and web page development software where you manipulate text and images directly without writing codes (such as HTML or dot codes) for each attribute. |
| X.25 | An international standard for packet switching, typically used with older telephone networks for data communications. See frame relay
|
| X.500 | A directory access protocol to enable a common standard for directories of information over a network. It has never caught on as well as its designers intended. See LDAP. |
| xDSL | See DSL. |
| XHTMLtm | eXtensible HyperText Markup Language. HTML re-written as an application of the XML language. See the W3C Working Draft: Building XHTML Modules |
| XML | Acronym for eXtensible Markup Language. A richer subset of SGML than HTML. It is a next step in the evolution of web data formats beyond HTML. See the World Wide Web Consortium (W3C) XML Page. |
| xmodem | An early form of file transmission for dialup and telnet connections. It is slower and uses smaller blocks of data (128 bits) than ymodem and zmodem. |
| XSL | Acronym for eXtensible Stylesheet Language, a style sheet companion to XML. |
| ymodem | A common form of file transmission for dialup and telnet connections, which uses 1K blocks of data. It has two forms--single file mode and batch mode. The single file form is sometimes called 1K xmodem, and the batch mode is sometimes called ymodem batch. Usage is not consistent. Zmodem is newer and more reliable. |
| Z39.50 | "American National Standard Z39.50: Information Retrieval Service Definition and Protocol Specification for Library Applications." This was designed to be a standard for connecting library computers and databases regardless of hardware and software. It could be used as a standard for many kinds of databases. It has not caught on, and there are many, many other database protocols in use today in and out of libraries. |
| zip | A method of file compression originally used with MSDOS and a file extension for files which are zip compressed. |
| zmodem | A very common form of file transmission, which can be used across dialup and telnet connections. It can be used in batch modes (for multiple files), and it is faster than the older xmodem and ymodem. In some implementations, it can resume a transfer after a connection has been broken and re-established. |
| zulu time | Zulu time, often used in US Government communications, is another way of saying Greenwich Mean Time (GMT). |
| zup? | Chat shorthand for "What'z up?". |
| 1000BaseT | An extension of 100BaseT that runs 10 times faster than 100BaseT. It's theoretically capable of 1Gbps (1000Mbps) transmission speed, and requires Category 6 cables to run over copper wire. Gigabit Ethernet can run over fiber-optic cabling as well. |
| 100BaseT | An extension of 10BaseT that runs 10 times faster than 10BaseT over copper wire. It's theoretically capable of 100Mbps transmission speed. The drawback for some installations is that it requires more expensive Category 5 cable to run at high speeds, where 10BaseT will run on Category 3, 4, or 5 cable. |
| 10Base5 | The original Ethernet specification, which is now more uncommon than 10Base2. It's also known as "thicknet." Cable speeds are typically up to 10Mbps. 10Base5 uses RG-11 coaxial cable in a bus topology configuration and has a maximum cable length of 500 meters, thus the 10(Mbps)Base5(00) name. |
| 128-bit Operating Systems | Operating systems may eventually be 128-bit. The ability to address 128 bits of memory space is something that may someday be necessary for huge databases, and will speed up operations. Of course, this will not happen until after there are some 128-bit chips to run them on. So far there are some chips with 128-bit registers and special operations, but they are not fully 128-bit. |
| 128-bit Video | The bits referred to here describe the bus between the GPU and the video memory. Typically, larger buses mean faster video, but it also depends on the transmission speed over that bus. The first 128-bit video cards had only 2 MB or 4 MB of video memory on them. |
| 1394 IEEE standard | A serial connection technology that promises to speed data at 200-800Mbps and up. Digital video camera manufacturers and Apple have embraced this connection standard. It is also available on PCs, but adoption is not as widespread. |
| 16-bit Operating Systems | DOS and Windows 3.x are 16-bit operating systems. They are limited in complexity and suffer instability and slow speed (compared to 32-bit OSes) when run on 32-bit processors like the 386DX-compatible chips and above. 16-bit chips were limited to 65,536 (2^16) Kbytes of memory, or 64 MB. This limitation caused momentum for the move to 32-bit chips and operating systems. |
| 2-tier architecture | Applications that have a code base (1-tier) separate from the database management system (1-tier), such as using Delphi to interact with Microsoft SQL Server (1+1 = 2 tier). The application code resides on the "fat client," which is used to process data. The problem with 2- tier applications is that they become complex and hard to support as the user base increases in size. What is good for 50 people may not work for 300 people. |
| 2.5G | Second generation wireless technology (2G) with incomplete third generation (3G) technology added to it. |
| 3-tier architecture | This architecture splits the user interface from the application logic. Servers handle the database management and application logic. This works out to less complexity at the client and a more scalable application. Additional user interfaces can be added easily because the user interface is the only thing that resides on the client. For example, you can easily let customers view data from the Web without changing the application that lets your salespeople work with their data. The three tiers are basically the application code that resides on the client, the database management and logic, and finally the database itself. |
| 32-bit Chips | This type of processor can run a 32-bit OS, such as Windows NT or some versions of UNIX. You can also run a 16-bit or lesser OS, but performance is not optimal. Intel's 386DX, 486, Pentium, and Pentium II/III/4 are all 32-bit processors. So are AMD's 386, 486, Athlon, and Duron. 32-bit processors can address up to 4 GB of memory. Although this may be plenty for a typical desktop machine, higher end servers, workstations, and desktops require more memory and use 64-bit processors. |
| 32-bit color depth | Anything that supports 32-bit color supports over four billion different colors (2^32, or 4,294,967,296 to be exact). Graphics cards are supporting up to and over 32-bit color, but the human eye cannot discern between colors at that level, and you need more memory on your graphics card to display 32-bit color at high resolutions. Color scanners, however, use 32-bit or higher color depth. This is a more accurate scan, even though the color difference between two pixels may not be perceptible. |
| 32-bit Memory Module | DRAM modules with 32 separate data lines. 72-pin SIMMs are 32-bit memory modules. Using 32-bit modules with 64-bit memory interfaces requires pairing (inserting two like modules at a time) the modules on the motherboard. |
| 32-bit Operating Systems | Windows NT, OS/2, and some flavors of UNIX are 32-bit operating systems. Windows 95 is a 32-bit operating system running on top of a 16-bit operating system (DOS). |
| 32-bit processor | This type of processor can run a 32-bit OS, such as Windows NT or some versions of UNIX. You can also run a 16-bit or lesser OS, but performance is not optimal. Intel's 386DX, 486, Pentium, and Pentium II/III/4 are all 32-bit processors. So are AMD's 386, 486, Athlon, and Duron. 32-bit processors can address up to 4 GB of memory. Although this may be plenty for a typical desktop machine, higher end servers, workstations, and desktops require more memory and use 64-bit processors. |
| 32-bit Video Cards | These are generally older cards that were only capable of addressing 1 MB of RAM. The 32 bits refers to the amount of information that can be transferred between the GPU on the video card and its local video memory. |
| 3DNow! | A set of 3D/multimedia floating point instructions first introduced in AMD's K6-2 processor. Newer processors from AMD support the instructions as well. 3DNow! consists of 21 new instructions, and 8 64-bit registers dedicated to the instructions. Some older Cyrix and IDT x86 processors also supported 3DNow!, but most chips are now using Intel-defined standards such as SSE and SSE2. |
| 48-bit color depth | Some scanners support 48-bit color, which offers the ability to identify over 281 trillion (2^48) colors. Such color differences may be imperceptible to the human eye, but as scanner DPI levels increase it helps keep colors more accurate. |
| 56Kflex | This was one of the two competing 56Kbps modem standards. It was developed by Rockwell and Lucent, and had more marketshare than USR's X2 technology due to the fact that it was licensed to over 700 modem manufacturers. Eventually, the V.90 modem standard made 56Kflex and X2 irrelevant. |
| 64-bit Chips | A processor that can run a 64-bit OS. The DEC Alpha is 64-bit, and so are Intel's Itanium and AMD's Opteron and Athlon 64 processors. The 386, 486, and Pentium and Pentium II/III/4 are all 32-bit processors, even though the Pentium and newer chips have 64-bit memory buses. |
| 64-bit Memory Module | DRAM modules with 64 separate data lines. SDRAM and DDR DIMMs are an example of 64- bit memory chips. |
| 64-bit Operating Systems | An operating system that is programmed to run on 64-bit processors. Some flavors of UNIX--and now Linux--are 64-bit operating systems designed to run on 64-bit chips. There are also preliminary versions of Microsoft Windows that are 64 bits so that they can run on 64-bit processors. |
| 64-bit processor | A processor that can run a 64-bit OS. The DEC Alpha is 64-bit, and so are Intel's Itanium and AMD's Opteron and Athlon 64 processors. The 386, 486, and Pentium and Pentium II/III/4 are all 32-bit processors, even though the Pentium and newer chips have 64-bit memory buses. |
| 64-bit Video Cards | Most current video cards have at least a 64-bit bus between the GPU and the video memory. The first 64- bit cards must had at least 2 MB of memory, up from 1 MB of memory on 32-bit cards. |
| 8 bits | A measure of memory. 8 bits make up 1 byte, and offer 256 (2^8) different combinations. |
| 8-bit Memory Modules | These DRAM modules have 8 separate data lines. 30-pin SIMMs are 8-bit memory modules. If you want to use them with a 32-bit chip such as a 386 or a 486 you need to put four of them in at a time--using the same size SIMM (all 1 MB SIMMs, all 2 MB SIMMs, etc.). With current microprocessors, 30-pin SIMMs are no longer used. |
| Abend | When Novell's NetWare network operating system crashes, it will usually toss up a message that starts with the term abend, which stands for Abnormal End. Much like the Windows NT BSOD (Blue Screen of Death), the abend screen signifies a problem condition that the operating system cannot handle. Most often, this term is used in phrases like "The server abended!" or "The server stopped abending after I updated the NIC drivers." |
| Accelerated Graphics Port | A dedicated expansion port that began to show up on motherboards in the second half of 1997. It bypasses the PCI bus and allows higher throughput from the graphics card to the processor and memory for speedier 3D graphics. Original AGP cards were "1x" versions that ran at 66MHz, offering 266MB/second throughput; but now AGP supports up to 8X data transfer speeds, which means the card still runs at 66MHz, but transfers 8x as much data per clock tick, upping the throughput to 2.1GB/second. Although the throughput is much greater, most graphics cards have a large amount of local memory and thus do not get much of a bonus from faster AGP speeds. |
| Access Speed | The average amount of time it takes for a floppy drive, hard drive, CD drive, or other drive to find any particular piece of data on a disk and send it to your PC. Access speed is typically listed in milliseconds (ms). |
| Accuracy | Accuracy is how close to the actual value you are. For example, if the number you are representing is 4 and you say it's 3, you are inaccurate by 1. |
| Accuracy vs. Precision | If the actual value is 4.321 and you say that it is 4.30, then you are precise to the first decimal place but inaccurate by .021. If a value is represented as a bulls-eye on a target, a group of guesses or measurements represented by closely grouped points have a high degree of precision. If that group is near the center, it is highly accurate as well. On a bullseye, think of accuracy as how close to the center your arrow hits, and your measurement of precision as how closely you can group your shots. |
| Ack | A response from a server to a network request. Basically, the server is saying, "I'm here, and I saw your request!" This also refers to the 6th ASCII character. |
| ACPI | This power management interface takes the power management out of the BIOS and gives control to the operating system (OS). Typically, a system's BIOS is only able to turn a device off after a certain period of inactivity. With ACPI, the user can instruct the OS to slow down the processor or enter sleep mode. This basically gives the OS, and thus the user, more control of power management. |
| Active Directory | A Microsoft technology based on LDAP that provides a unified view and way to manage all objects on a network. Microsoft created Active Directory as a response to Novell's NDS system that allows administrators to control large networks in a similar manner. Active Directory was first introduced with Windows 2000, and many organizations are moving from the domain model of Windows NT to the Active Directory model of Windows 2000 because |
| Active Matrix | LCD panels that are active matrix have a sharper, brighter image than those with passive matrix screens. They can also continue to be seen at much greater angles off of central viewing. In the early days of the LCD active matrix panels cost more to produce. The "active" part of the word describes the use of a transistor or diode that actively controls each pixel. |
| Active Movie | A Microsoft technology used for streaming video and audio over the Internet. It is an ActiveX control. |
| Active Server Pages | Microsoft created this technology and bundled it with its IIS webserver software. It is designed to allow easy combination of HTML, scripts (such as JavaScript and Microsoft's VBScript), and ActiveX. Active Server Pages promise to be more robust than CGI when handling large amounts of client requests, but that competition is close and ongoing. |
| Active Template Library | A group of routines provided by Microsoft that can be used to help more easily create ASP, ActiveX, and COM objects in C++. |
| ActiveX | A Microsoft technology that uses COM technology, and is designed to enable easier embedding of interactive objects, and often multimedia, on Web pages. To interact with ActiveX on sites that support it, your browser must support it as well. |
| Actuator | The part of a hard drive that the read/write arms attach to. It is controlled by an electrical signal sent to it that extends or retracts the arms so that they can move across the tracks on the drive platters. Nowadays the movement of these lightweight arms is very fast, appearing like a flicker if you were to view it. |
| ADC | An electronic device that converts analog signals into digital signals. For example, the input port of a sound card can accept analog input from a microphone, and it uses an ADC to convert the analog signal to a digital signal that can be sent along to other parts of your computer. |
| ADSL | A technology that is the phone company's answer to cable modems. It supports data speeds over 7Mbps downstream (to the user) and slower speeds upstream (to the Internet). Asymmetric describes how the upstream speed is different than the downstream speed. |
| Advanced Configuration and Power Interface | This power management interface takes the power management out of the BIOS and gives control to the operating system (OS). Typically, a system's BIOS is only able to turn a device off after a certain period of inactivity. With ACPI, the user can instruct the OS to slow down the processor or enter sleep mode. This basically gives the OS, and thus the user, more control of power management. |
| Advanced Intelligent Tape | A tape format initially introduced in 1996. AIT promises low tape tension for longer tape life, very clean tape media, and high capacity and transfer rates. The AIT-1 specification offers 35 GB of native storage per tape and 3MB/second transfer rates; the AIT-2 standard offers 50 GB of native storage with transfer rates of 6MB/second; and AIT-3 boosts that up to 100 GB and 12MB/second. Each AIT tape contains a small memory chip which keeps track of where files are located on the tape, allowing for faster file location than scanning the entire tape until you hit the file you are looking for. AIT competes against DLT at the high-end of the tape drive market. |
| Advanced Research Projects Agency Network | A network of interconnected computers that formed the original Internet. The United States military funded the ARPANet, and construction was started in 1968. It was designed to be a redundant network of computers so that no single disruption could break down communications between other units. The ARPANet expanded to universities for research, and soon after the Internet was born. |
| Advanced SCSI Programming Interface | This was developed by Adaptec so that different devices could be controlled by different SCSI cards, and therefore the SCSI card version would not matter. Basically, if the correct ASPI driver is being used, you can send the same command to any Adaptec SCSI card to make something happen to a device. Most commonly, ASPI is associated with CD-ROM and CD-RW drives. |
| AFAIK | Online speak for "As Far As I Know" |
| AGP | A dedicated expansion port that began to show up on motherboards in the second half of 1997. It bypasses the PCI bus and allows higher throughput from the graphics card to the processor and memory for speedier 3D graphics. Original AGP cards were "1x" versions that ran at 66MHz, offering 266MB/second throughput; but now AGP supports up to 8X data transfer speeds, which means the card still runs at 66MHz, but transfers 8x as much data per clock tick, upping the throughput to 2.1GB/second. Although the throughput is much greater, most graphics cards have a large amount of local memory and thus do not get much of a bonus from faster AGP speeds. |
| AGP 1x | The original parallel AGP standard that operates on a 32-bit bus at 66MHz speed for a maximum data transfer rate of 256MB/second. |
| AGP 2x | This AGP standard features a parallel 32-bit bus running at 133MHz effectively (66MHz*2 literally) for a maximum data transfer rate of 512MB/second. AGP 2x slots will accept AGP 1x cards as well as 2x cards. |
| AGP 4x | This AGP standard features a parallel 32-bit bus running at 266MHz effectively (66MHz*4 literally) for a maximum data transfer rate of 1GB/second. AGP 4x slots are compatible with 1x, 2x, and 4x graphics cards. |
| AGP 8x | This AGP standard features a parallel 32-bit bus running at 533MHz effectively (66MHz*8 literally) for a maximum data transfer rate of 2GB/second. This is the last parallel form of AGP, and is compatible with all previous AGP cards. |
| AGP Aperture | The amount of system memory that the AGP board can address and use as graphics memory. Often, the default setting is 64 MB. Increasing this value (assuming you have enough system memory) may increase performance in 3D games that use more memory than is available on the video card. Once an AGP video card is installed, this setting can usually be changed in the computer's BIOS. |
| AGP Pro | This AGP standard allows the graphics card to draw more than four times the electrical power of the regular AGP 4x standard, i.e., 110 watts up from 25 watts. AGP Pro transfers data at the same speed as AGP 4x and requires a special AGP Pro slot that is larger than the standard AGP slot. |
| Air Cooling | Cooling that involves a heatsink and/or fan. Even though a metal heatsink may make contact with the microprocessor package (or whatever is being cooled), the heatsink ultimately exchanges the heat with air, whether a fan is used or not. Contrast this with water cooling. Air cooling is less efficient than water cooling. |
| Air gap | A type of network security in which a network is secured, at least in part, by keeping it physically separate from other local networks and the Internet. This can be an effective type of security, but it is also limiting in that clients may not be able to get to all resources they need from a single computer. |
| AIT | A tape format initially introduced in 1996. AIT promises low tape tension for longer tape life, very clean tape media, and high capacity and transfer rates. The AIT-1 specification offers 35 GB of native storage per tape and 3MB/second transfer rates; the AIT-2 standard offers 50 GB of native storage with transfer rates of 6MB/second; and AIT-3 boosts that up to 100 GB and 12MB/second. Each AIT tape contains a small memory chip which keeps track of where files are located on the tape, allowing for faster file location than scanning the entire tape until you hit the file you are looking for. AIT competes against DLT at the high-end of the tape drive market. |
| AIX | An open IBM operating system based on UNIX. IBM produces a version of AIX for its RS/6000 mainframe hardware. |
| Algorithm | A step-by-step method of accomplishing a task. For instance, a sorting algorithm may be like this: 1) Progress down your list from the top; 2) When you encounter something that is less than the last item swap the two; 3) Repeat Steps 1 and 2 until you reach the end of your list. This is commonly known as a Bubble Sort, as it seems to bubble items to the top of the list. |
| Alpha | A term given to a very early version of a hardware or software product which is not yet stable and may lack features. After some testing and some revision, the product will assume beta status. |
| Alpha Blending | This allows two objects to be visually blended together. This is primarily used for 3D atmospheric and environmental effects. It allows such things as "fogging," where an image is rendered behind another translucent image, which creates the effect of looking though fog or looking down through a pool and seeing the bottom. It also allows Depth Cueing, which is the lowering of the intensity of lighting to make an object appear farther away. |
| Alpha Test | A term given to a very early version of a hardware or software product which is not yet stable and may lack features. After some testing and some revision, the product will assume beta status. |
| Alt | 1. There is an Alt key found on a computer keyboard. The Alt key functions much like a third Ctrl/Shift key in that it alters the value of other characters pressed on the keyboard. 2. The term Alt has also been used to refer to using the Esc key (ASCII 27) to alter the next input. 3. Finally, Alt is used as a prefix for usenet newsgroups that can be created without going through the standard voting procedures, such as alt.pictures.angry.pandas. |
| Alternating Current | A type of electrical current that reverses its direction at a regular interval, and can be represented by a sine wave. Alternating current is the type of current typically found in a wall outlet. You plug your TV, computer, refrigerator, etc. into alternating current. These devices then change the alternating current into direct current (DC) so that they can use the current properly. Alternating current is the reason that we need such complex power supplies, or power bricks, to regulate the flow of current in electronic devices. |
| ALU | The part of the CPU that actually does the work of adding, subtracting, multiplying, and dividing, including OR, AND, and NOT operations. The ALU is an execution unit, like the FPU, that is fed with data from the CPU registers. |
| Amdahl's Law | This states that even a small percentage of "serial" code (code which can't be parallelized) can cause the speed of a program not to increase a great deal as the amount of parallel processors are increased towards infinity. This theoretical law was used at one time to argue that massively parallel computing is worthless, but it's pretty clear by now that massively parallel computers have their uses. See also Gustafson's Law. |
| American National Standards Institution | This organization represents the United States in the International Organization for Standardization (ISO). It works to develop coding and signaling standards. |
| American Standard Code for Information Interchange | Pronounced "ass-kee." This is a standard means of representing characters, consisting of 256 characters. The first 128 characters are standardized, and the first 32 of those are control codes, which don't really represent visible characters but rather codes that can be used for text formatting or actions, such as making the computer beep or clearing the screen. After the 32 control codes, the next 96 standardized characters represent numbers, letters (both uppercase and lowercase), and standard punctuation marks. The last 128 characters represent different things on different platforms. ASCII is being largely supplanted by Unicode. |
| Amp | The base unit of electrical current, which is the rate of flow of an electrical charge. |
| Ampere | The base unit of electrical current, which is the rate of flow of an electrical charge. |
| Amplitude Modulation | A means of transmitting and receiving radio waves that is based on variances in the amplitude of the radio waves. See also FM. |
| AMR | An Intel specification designed to move the analog I/O functions of sound cards and modems onto a riser card. It allows motherboards to have an I/O slot built into them to make it easier to integrate audio and modem functions onto a motherboard. The specification does not define "an aftermarket standard I/O slot," according to Intel. Basically, the slot is supposed to be filled when you buy a motherboard, with the motherboard manufacturer's choice of modem/audio functions. |
| Analog | Analog refers to a representation of a quantity that varies over any continuous range of values. Analog signals can be thought of as pure in nature and not processed. Thus, the debate over whether record albums (analog representation of sound, where the sound is generated by physical ridges on the record) sound better thanCDs (digital representation of sound, where variation is limited by the encoding level). Think of nature as analog. Analog values are exact, but it is impossible to correct errors in reproduction (e.g., a scratch on a record). |
| Analog Control | An analog control changes value in non-discrete steps. You can tune an analog control to non-distinct values (selecting 107.41234723947392... as the radio station you are tuned to instead of 107.40000000000000...). In some cases, like for volume, analog controls are better. Have you ever used a digital volume control on a new TV, and one setting is too loud while the other is too soft? You just can't get it in between. However, for channel tuning, where values change by fixed steps, a digital control is much better--you just don't need to get in between channel 4 and 5. Also see Digital Control |
| Analog to Digital Convertor | An electronic device that converts analog signals into digital signals. For example, the input port of a sound card can accept analog input from a microphone, and it uses an ADC to convert the analog signal to a digital signal that can be sent along to other parts of your computer. |
| Anonymous FTP | FTP services requiring no specific authentication, using a login name of "anonymous" and your e- mail address as a password. |
| ANSI | This organization represents the United States in the International Organization for Standardization (ISO). It works to develop coding and signaling standards. |
| Anycast | A method available in IPv6 of sending information over a network. It allows a device to send data to the nearest (fastest) of a group of receivers. |
| Apache | In early 1995, a group of webmasters decided to get together and expand on the original NCSA HTTP daemon (webserver software), and Apache was born. Today, Apache is the most used webserver on the Internet. Apache is Open Source freeware, and is available for Linux, Windows, and many versions of UNIX. |
| Aperture Grill | This form of mask is similar to a shadow mask, but instead of a sheet of metal with holes poked into it it is a series of fine, vertically-aligned metal wires. |
| API | APIs allow you to program to a pre-constructed interface (the API) instead of programming a device or piece of software directly. This allows for faster development, since programming to a device's API is designed to be easier than programming to a device directly. APIs allow you to program without having intimate knowledge of the device or software to which you are sending commands. For example, the OpenGL API allows you to create 3D effects without actually knowing the innards of your video card. |
| Applet | A derivation of "application." You use the Applet tag in HTML code to define calls to Java-based applications within a browser. Thus, any Java program accessible through a Java-enabled browser can be referred to as an applet or Java Applet. |
| Application Programming Interface | APIs allow you to program to a pre-constructed interface (the API) instead of programming a device or piece of software directly. This allows for faster development, since programming to a device's API is designed to be easier than programming to a device directly. APIs allow you to program without having intimate knowledge of the device or software to which you are sending commands. For example, the OpenGL API allows you to create 3D effects without actually knowing the innards of your video card. |
| Application Service Provider | A company that provides remote access to applications, typically over the Internet. ASPs are used when an organization finds it more cost effective to have someone else host its applications than to host them itself. The applications served up can be as simple as access to a remote fileserver, or as complex as running an order entry system through your browser. The ASP provides the servers, network access, and applications to be used, typically for a monthly or yearly subscription fee. |
| Application-Specific Integrated Circuit | An ASIC is a circuit designed for a very specific purpose, such as the processors in PDAs or the chips on a motherboard chipset. ASICs contrast with more general-purpose devices such as memory chips or x86 processors that can be used in many different applications. |
| Apt-get | Part of "apt," a package retrieval tool that automatically connects to known Linux package repositories and checks for new packages. It also works out dependencies between packages. Apt-get is used with the Debian Linux distribution. |
| Archie | A service that indexes files found on FTP servers. It is not used much anymore, due to the popularity of the Web and large download sites that are already well indexed. To get your archie results you use an archie client to query an archie server. |
| Archive | As a noun, this refers generally to any type of backed-up data. It can refer to tapes, disks, or just simply a group of data that is an old copy of current data. That copy could be one minute old or several years old. As a verb, archive is the act of backing up data or creating an archive. |
| Areal Density | This typically refers to the amount of data that can be stored on a one-inch square of material. It's usually represented in billions of bits per square inch on a hard drive platter. For example, the first Toshiba 30 GB hard drives that fit into 2.5" form factors had an areal density of 26.7 billion bits. Hard drives with higher areal densities can store more information in an equal space than those with lower areal densities. Hard drive manufacturers are constantly improving areal densities so that they can produce higher capacity drives without making them physically larger. |
| Argument | What you have with your girlfriend when she wants you to stop using your computer so much. Actually, argument refers to the value with which you call a procedure. For example, if you wrote a line of code that said "goto 140" telling your program to go to line 140, the argument is "140." Some procedures will accept multiple arguments, or alternately, require no arguments. |
| Arithmetic Logic Unit | The part of the CPU that actually does the work of adding, subtracting, multiplying, and dividing, including OR, AND, and NOT operations. The ALU is an execution unit, like the FPU, that is fed with data from the CPU registers. |
| ARPANet | A network of interconnected computers that formed the original Internet. The United States military funded the ARPANet, and construction was started in 1968. It was designed to be a redundant network of computers so that no single disruption could break down communications between other units. The ARPANet expanded to universities for research, and soon after the Internet was born. |
| Array | 1. This can be an abbreviation for a group of hard drives functioning as a RAID (Redundant Array of Inexpensive Drives). 2. This also describes a common data structure that holds values in a consecutively numbered group, such as A[1]...[7], where A is an array of 7 different values. There are also multi-dimensional arrays such as A[1,1,1]...A[8,8,8], which can hold many values and still be fairly simply referenced. |
| Arrow keys | The four keys on a computer keyboard that are commonly used to move the cursor around in programs that support such movement. Some keyboards feature 8 arrow keys, which include the four standard directions (up, down, left, right) and the four diagonals. |
| ASCII | Pronounced "ass-kee." This is a standard means of representing characters, consisting of 256 characters. The first 128 characters are standardized, and the first 32 of those are control codes, which don't really represent visible characters but rather codes that can be used for text formatting or actions, such as making the computer beep or clearing the screen. After the 32 control codes, the next 96 standardized characters represent numbers, letters (both uppercase and lowercase), and standard punctuation marks. The last 128 characters represent different things on different platforms. ASCII is being largely supplanted by Unicode. |
| ASIC | An ASIC is a circuit designed for a very specific purpose, such as the processors in PDAs or the chips on a motherboard chipset. ASICs contrast with more general-purpose devices such as memory chips or x86 processors that can be used in many different applications. |
| ASP | see Active Server Pages, Application Service Provider, or Average Selling Price |
| Aspect Ratio | The ratio of the width by the height on a monitor or television screen. Most TVs and monitors have a 4x3 aspect ratio--the screens are 4 units wide and 3 units high. A movie screen has an aspect ratio of 16x9 (a bit wider than 5x3), and that's why we have letterboxed movies (when you show a movie in true form on a TV you get black boxes on the top and bottom of the screen). HDTV screens today and some monitors support 16x9 aspect ratios, but most televisions and monitors still retain the 4x3 aspect ratio. |
| ASPI | This was developed by Adaptec so that different devices could be controlled by different SCSI cards, and therefore the SCSI card version would not matter. Basically, if the correct ASPI driver is being used, you can send the same command to any Adaptec SCSI card to make something happen to a device. Most commonly, ASPI is associated with CD-ROM and CD-RW drives. |
| Assembly Language | A programming language specific to a microprocessor. It is a very low-level language, where you actually give the processor instructions like "MOV A,B", which moves a value from one register to another. As you might imagine, programming directly in assembly language is quite tedious. Thus, higher level languages, such as C++, Visual Basic, or Java, are normally used and then compiled into assembly language specific to the microprocessor on which the program will be run. The compiler tries to optimize the code during this process (e.g., "MOV A,B" followed by "MOV B,C" might be replaced by "MOV A,C"). Depending on how elegant the optimization is, the code may run faster than if no optimization is used. Today, very small and fast programs can be created by using assembly language (defeating code bloat), but assembly language programming is becoming a dying art. |
| Asymmetric Digital Subscriber Line | A technology that is the phone company's answer to cable modems. It supports data speeds over 7Mbps downstream (to the user) and slower speeds upstream (to the Internet). Asymmetric describes how the upstream speed is different than the downstream speed. |
| Asynchronous Communication | This method of transferring data does so without a specific timing mechanism between the two communicating parties. The party receiving data isn't expecting more data at any set interval. |
| Asynchronous Transfer Mode | A networking protocol initially designed to move multimedia data around with high reliability and speed. It uses small, fixed-size cells of data that can be more easily controlled and kept at specific service levels than TCP/IP. Some ISPs use ATM as the protocol for their backbones. |
| AT Attachment | A storage (hard drive, CD-ROM, etc.) interface more commonly known as IDE. The "AT" refers to the IBM-AT computer where this interface was first used. |
| AT Attachment Packet Interface | This interface is part of EIDE, and it allows a PC to control CD-ROM drives and tape drives across the IDE interface. |
| AT Form Factor | A PC form factor that describes the way a motherboard fits into a case and works with a power supply. Thus, you match an AT power supply with an AT case and an AT motherboard. Some of the things common to AT motherboards are a large 5-pin DIN socket for plugging a keyboard in, and serial and parallel port interfaces available via riser cards that are not part of the motherboard itself. The AT form factor was succeeded by the ATX form factor. |
| ATA | A storage (hard drive, CD-ROM, etc.) interface more commonly known as IDE. The "AT" refers to the IBM-AT computer where this interface was first used. |
| ATA/100 | Another extension to the ATA interface that adds a 50% increase in top speed over ATA/66, getting to 100MB/second, up from 66MB/second. This standard also adds some additional error-checking not found in earlier ATA standards. Like Ultra ATA/66, ATA/100 requires an 80-conductor cable to work at full speed. |
| ATA/133 | This refers to what is most probably the final extension to the parallel ATA connection standard. The proposal was created by Maxtor, and allows a top data transfer rate of 133 megabytes per second. Intel didn't support this standard in its chipsets, instead opting to wait for Serial ATA. See Serial ATA for further details. |
| ATA/33 | An extension to the ATA interface (IDE) that effectively doubles the top data transfer speed of IDE from 16.6MBytes/second up to 33 MBytes/second. Also known as Ultra-IDE. |
| ATA/66 | An extension to the ATA interface (IDE) proposed by Quantum that effectively doubles the data transfer speed of the Ultra ATA/33 interface to 66MBps. To achieve the increase in speed you must use a special 80-conductor cable with 40 data lines and 40 ground lines to keep the signal stable. |
| ATAPI | This interface is part of EIDE, and it allows a PC to control CD-ROM drives and tape drives across the IDE interface. |
| ATL | A group of routines provided by Microsoft that can be used to help more easily create ASP, ActiveX, and COM objects in C++. |
| ATM | A networking protocol initially designed to move multimedia data around with high reliability and speed. It uses small, fixed-size cells of data that can be more easily controlled and kept at specific service levels than TCP/IP. Some ISPs use ATM as the protocol for their backbones. |
| Attachment | A file embedded in an e-mail message. It is possible to have one or more attachments embedded in an e-mail message. If you are sending or receiving attachments, you must have an e-mail client that supports MIME encoding, or the attachments will show up in encoded form, which basically looks like a large block of numbers and letters. |
| ATX | The ATX form factor specification takes the original Baby AT-sized motherboard, rotates it 90 degrees, and calls for a power supply with a side-mounted fan that cools not only the power supply, but also the processor and add-in boards. This new approach was designed to lower costs and provide better motherboard placement in an ATX case. In addition, the ATX form factor introduced a large set of I/O ports that are wired directly to the motherboard, and standard support for PS/2 keyboard and mouse connections. |
| ATX Form Factor | The ATX form factor specification takes the original Baby AT-sized motherboard, rotates it 90 degrees, and calls for a power supply with a side-mounted fan that cools not only the power supply, but also the processor and add-in boards. This new approach was designed to lower costs and provide better motherboard placement in an ATX case. In addition, the ATX form factor introduced a large set of I/O ports that are wired directly to the motherboard, and standard support for PS/2 keyboard and mouse connections. |
| ATX12V | A superset of the ATX form factor that is used for systems with the Pentium 4 processor. It features a power supply with an extra four-pin connector for 12 volt power to the motherboard so that the processor has enough power. There is also a 6-pin auxiliary connector for additional 3.3 or 5 volt power. |
| Audio Modem Riser | An Intel specification designed to move the analog I/O functions of sound cards and modems onto a riser card. It allows motherboards to have an I/O slot built into them to make it easier to integrate audio and modem functions onto a motherboard. The specification does not define "an aftermarket standard I/O slot," according to Intel. Basically, the slot is supposed to be filled when you buy a motherboard, with the motherboard manufacturer's choice of modem/audio functions. |
| Audio Video Interleave | A Microsoft-specified format for saving audio and/or video clips, referred to by Windows as "Video for Windows." You can play the files through the Media Player in Windows or through many popular browser plug-in multimedia players. Files of this type have a .avi extension. |
| AUI | A synonym for the 10Base5 Thicknet Ethernet standard. |
| Authentication | A process of proving the identity of a computer or computer user. For users, it generally involves a user name and password. Computers usually pass a code that identifies that they are part of a network. |
| Availability | A measure of how much time a network or a connection is running. Generally the equation is: Time Running / Time Measured (time running divided by time measured). Thus, if you measured something for 20 minutes and it was only up for 19 of them, you'd have 95% availability. |
| Average Selling Price | This term is used in the microchip manufacturing world. Companies like AMD and Intel strive for high ASPs. The ASP is an indication not only of direct profits, but how well a company is keeping up with the technology curve. It is not uncommon for Intel to have an ASP of around US$100 and AMD to be close behind. |
| AVI | A Microsoft-specified format for saving audio and/or video clips, referred to by Windows as "Video for Windows." You can play the files through the Media Player in Windows or through many popular browser plug-in multimedia players. Files of this type have a .avi extension. |
| Baby AT | A motherboard form factor that has the same traits as the standard AT form factor, such as AT power connectors and keyboard input port. However, it is smaller in size, and can be utilized in smaller computer cases. |
| Back-end | A type of program or process that is not directly accessed by a user. Often it will carry out its tasks independently of the front-end or user interface. For example, a user could request data from a database, not knowing that the data is refreshed on the back-end on a daily basis. |
| Backplane | As opposed to standard cabling schemes where flexible wires are used, a backplane refers to a rigid circuit board that will support higher connection speeds and more logic. For example, many SCSI systems today ship with small SCSI backplanes because the transfer rate of SCSI is getting high enough that standard cables are causing problems when connecting devices. Another example of a backplane is in network connection devices, such as large enterprise scale switches, routers, or PBXs. Some of these devices have a high- speed backplane, and you can plug a group of slower network connection devices into the high-speed backplane. |
| Backside Bus | In some architectures, such as Socket 7, the speed of the backside bus determined how fast the microprocessor could talk to its external L2 cache. Newer architectures, such as Slot 1 and most architectures today, have a dedicated L2 cache bus (or dedicated on-chip L2 cache), and a backside bus is no longer required at all. |
| Backup Domain Controller | One or more computers running Windows NT that act as a backup to the primary domain controller (PDC). These machines can authenticate security requests just like the primary domain controller, and will take over for the PDC if it is not available. However, a BDC will remain a BDC until it is manually promoted to a PDC by a domain administrator. With Active Directory Windows no longer requires the sometimes confusing primary and backup domain controllers, just domain controllers instead. |
| Balance | The control for the level of sound coming out of the left or right speakers. If you turn the balance control all the way in either direction, you can isolate the sound to the left or right channel, which helps in troubleshooting whether both speakers are connected properly. Other than that, the balance control can fine-tune volume levels to compensate for sound conditions in the room. |
| Ball Grid Array | As opposed to a pin grid array (PGA), a ball grid array is a type of microchip connection methodology. Ball grid array chips typically use a group of solder dots, or balls, arranged in concentric rectangles to connect to a circuit board. BGA chips are often used in mobile applications where PGA chips would take up too much space due to the length of the pins used to connect the chips to the circuit board. More and more designs are moving to BGA form factors. |
| Banner ad | The most common form of advertising found on the Web. The traditional size of a banner ad is 468 by 60 pixels, but there are many other sizes in general use. Banner ads are typically animated GIF graphics or Flash animations that are simply clicked on to go to the website of the advertiser, but can also contain rich media that allows for some degree of interaction with the ad besides a simple click. |
| BASIC | This programming language was developed in the mid '60s. The language was constructed of simple, English-like commands that were run through an interpreter, line by line, each time the program was "run." This caused BASIC programs to be slow. Nowadays compilers have been developed to speed up BASIC programs, and recent versions of BASIC can do anything that other programming languages can. |
| Basic Input Output System | A program stored on your motherboard that controls all of the interaction between your components and your chipset. Simple access to video, keyboard, hard drive, floppy, CD-ROM, and other devices--that are enough to get an operating system loaded up--are included in the BIOS. Your BIOS is there to get things started for the operating system. |
| Batch | A group of commands that are executed one at a time. See also Batch File |
| Batch File | A file in a DOS/Windows environment with the .bat extension. This file type is executable in DOS or at a Windows command prompt. Batch programs are written in a batch programming language that utilizes a superset of standard DOS commands. |
| Battery | A device consisting of one or more cells that can produce a direct current by converting chemical energy to electrical energy. Batteries typically have positive and negative terminals that must be connected for current to flow. |
| BBIAB | Online speak for "Be Back In A Bit" |
| BCP | A program used to copy databases or parts of databases in Sybase and Microsoft SQL Server environments. It was at first a command line program, but graphical interface programs have been put on top of it to make it more friendly. |
| BDC | One or more computers running Windows NT that act as a backup to the primary domain controller (PDC). These machines can authenticate security requests just like the primary domain controller, and will take over for the PDC if it is not available. However, a BDC will remain a BDC until it is manually promoted to a PDC by a domain administrator. With Active Directory Windows no longer requires the sometimes confusing primary and backup domain controllers, just domain controllers instead. |
| BEDO | A type of EDO RAM that can read three consecutive memory locations in three clock cycles--a 1-1-1 burst. This makes BEDO RAM much faster at reading large blocks of data than standard EDO RAM. However, it cannot operate faster than 66MHz, limiting its applications in today's computers. Burst EDO was never more than a niche technology. |
| Beep Code | When you turn on your PC--and all is well--you typically hear a single beep from your computer speaker, signaling that all is OK. If things are wrong--and the computer BIOS senses that things are wrong--a series of beeps will be emitted. This is the beep code. Based on the number of beeps, you can look up the meaning in your motherboard documentation and often diagnose the problem. Obvious things to check are whether your video card, processor, and/or memory are plugged in and seated properly. |
| Beginner's All-purpose Symbolic Instruction Code | This programming language was developed in the mid '60s. The language was constructed of simple, English-like commands that were run through an interpreter, line by line, each time the program was "run." This caused BASIC programs to be slow. Nowadays compilers have been developed to speed up BASIC programs, and recent versions of BASIC can do anything that other programming languages can. |
| Benchmarking | The process of measuring the performance of hardware or software in a specifically defined and strictly controlled environment. The benchmarking result is usually represented by a time or number rating that corresponds to how quickly certain tasks can be completed. The benchmark must be reproducible, of course, to have any meaning. |
| BeOS | An operating system designed by Be, Inc. The original goal of BeOS was to create an OS able to process multiple digital media streams efficiently, with no loss of performance. This contrasts to the design goal of the Windows OS, which had trouble with such operations, especially in older versions. The BeOS was originally designed to work on the PowerPC architecture, and was then ported to he x86 architecture. Be Incorporated, the company that made BeOS, was dissolved in November 2001 and its assets were sold to Palm, Inc. |
| Beowulf | A cluster of computers connected to a high-speed private network, running Linux, FreeBSD, or another free OS, and using Beowulf software to function like a single massively parallel computer. All nodes in the system are dedicated to running cluster jobs, and do not function as client machines. A Beowulf cluster is designed for high speed over-reliability. Typically there is only one node that is connected outside of the private network. |
| Beowulf Project | This project serves as a repository of information for creating clusters of computers, called Beowulfs, that function as one massively parallel machine. It seeks to further the knowledge of producing a Beowulf cluster and has no centralized management. The Beowulf Project began in 1994 with the creation of a 16-node cluster of machines at a research center operated by NASA, and quickly spread to the creation of other clusters of computers assembled with off-the-shelf hardware that could perform some tasks much faster than a single machine, and for much cheaper than purchasing an expensive supercomputer. |
| Berkeley Internet Named Domain | A DNS software package for UNIX/Linux machines. It contains a DNS server, API library, and tools. It is the most widely used DNS server, and most of the DNS servers on the Internet are running BIND. Bind can also refer to the linking of a networking protocol to a network card. |
| Beta | A term given to a product that isn't ready for public consumption, but is good enough for a wider testing scope. Many companies publicly release their beta software to a fraction of their users to let them get experience with the new software while the company gets feedback on bugs and features. Also see Alpha |
| BGA | As opposed to a pin grid array (PGA), a ball grid array is a type of microchip connection methodology. Ball grid array chips typically use a group of solder dots, or balls, arranged in concentric rectangles to connect to a circuit board. BGA chips are often used in mobile applications where PGA chips would take up too much space due to the length of the pins used to connect the chips to the circuit board. More and more designs are moving to BGA form factors. |
| BGP | The protocol used by the core routers on the Internet to route TCP/IP packets. BGP replaces the older Exterior Gateway Protocol. Core routers use BGP exchange routing information to determine optimal routing paths and also exchange TCP/IP data packets. |
| Bilinear Filtering | Used to smooth flat surfaces by averaging the colors of adjacent pixels, which blurs them and removes blockiness when viewed up close. |
| Binary code | Binary consists of a string of bits, with bits represented by 1s and 0s, e.g., 01010111000000001. The "bi" refers to base 2 mathematical representation (1s and 0s). |
| Binary Large OBject | A BLOB is a data type used in a relational database that can contain any type of binary data, including sound, video, graphics, etc. |
| Binary Search | A search technique that splits an ordered list into halves until a result is found. Thus, it splits the list into a top and bottom half, then picks the half that the search term is located in (which can be determined because this search is used on ordered lists) and splits that in half, and so on until the search term is reached. The binary search uses a logarithmic (log2) amount of splits to locate its search term. For example, an ordered list of a million items can be searched in a maximum of 20 splits, a billion can be searched in 30, and so on. |
| Binary Tree | An ordered tree where each node has no more than two child nodes. Child nodes are typically distinguished as left and right child nodes. |
| BIND | A DNS software package for UNIX/Linux machines. It contains a DNS server, API library, and tools. It is the most widely used DNS server, and most of the DNS servers on the Internet are running BIND. Bind can also refer to the linking of a networking protocol to a network card. Bind can also refer to the linking of a networking protocol to a network card. |
| BIOS | A program stored on your motherboard that controls all of the interaction between your components and your chipset. Simple access to video, keyboard, hard drive, floppy, CD-ROM, and other devices--that are enough to get an operating system loaded up--are included in the BIOS. Your BIOS is there to get things started for the operating system. |
| Bistable Multivibrator | A simple element of memory made up of an assembly of logic gates. Based on inputs, the state of a flip-flop can be changed back and forth, affecting the future output of the flip-flop. |
| Bit depth | How many bits it takes to represent the color in one pixel. The greater the bit depth, the more colors you can potentially display, and the more power it takes to represent a screen full of pixels at that bit depth. Common bit depths are 16 and 32 bits. Bit depth of 1 would only enable 2 colors, bit depth of 2 enables 4 colors, and so on, where the amount of potential colors can be determined by 2^bit_depth. |
| Bit Rate | The amount of bits per second used to encode audio data in an MP3 or other compressed audio file. Bit rate is typically listed in kilobits per second (kbps). Higher bit rates typically mean better sound quality, but that's just one of the factors involved. Typically, bit rates range between 96-256, but any rate is possible. |
| Bitmap font | A font where each character is stored as a bitmap graphic. These fonts are not easy to scale to different sizes. |
| Bits per second | This is generally a measure of how fast some device communicates, usually in thousands of bits per second (Kbps) or millions of bits per second (Mbps). See also Bytes per second |
| Black box | Anything that you put input into and get output from, but don't know what's inside or how it works. The black represents the box being opaque so that you cannot see inside. |
| Black hat | A malicious hacker. If a hacker finds a security hole and exploits it or lets others know about it before letting the people affected by the hole know about it, that hacker is described as a black hat hacker. This term comes from cowboy movies, where the bad guy would wear a black hat. |
| Blind Carbon Copy | When sending an e-mail, if you BCC someone you are sending him or her a copy of your e-mail, but not allowing the recipients in the "To" or "CC" fields of your e-mail client to know that the BCC recipient was sent the message as well. BCC is often used for covert company communications, such as if you are getting irritated at someone and want to let someone else in on it without alerting the party you are irritated about, or if you are sending the CEO of your company a mail telling him or her he or she is wrong about something and want to BCC copies to your friends to gloat over it. Use BCC with caution. One of the most common uses of BCC is when sending mass e-mails; just send the e-mail to yourself and BCC it to the whole group you are sending to. That way, your mailing list is not known to any of the members. |
| BLOB | A BLOB is a data type used in a relational database that can contain any type of binary data, including sound, video, graphics, etc. |
| Block Mode | A setting in the computer BIOS relating to IDE hard drives. The setting determines the type of Logical Block Addressing that will be used to translate large hard drives properly to the computer BIOS. On most machines with up-to-date BIOSes, you can set this to "Auto" and have hard drives recognized with no further specification on your part. If that doesn't work, you may need to tinker with other settings or use the software provided by the hard drive manufacturer for software translation. |
| BNC | A connector type for 10Base2 or Thin-Net networks. Shaped like the letter T, it connects coaxial cables. The "T" has two male connectors and one female connector. The female connector can connect to the male connection of an Ethernet card that supports BNC connections, or remain empty. The male connectors link to coaxial cable or a terminator. The BNC part stands for either British Naval Connector, British Nut Connector, or Bayonet Neill-Concelman ... or perhaps it stands for some combination of those terms. Neill and Concelman are the names of the inventors of the BNC Connector. |
| Boolean logic | The form of logic where every answer is either true or false. Alternately, you can think of it as either 0 or 1, where 0 = false and 1 = true. |
| Boot | A verb meaning to load into physical memory (RAM) from the hard drive (or other media). You can say that you are booting your machine, or that your operating system is booting up. |
| Boot disk | A floppy disk or other disk media that contains the files needed to start an operating system. PCs are often set up so that the floppy and/or CD/DVD drive is checked first for a boot disk. |
| Boot Record | The first sector on a hard disk or other disk media. When a computer boots up it searches for a master boot record wherever the BIOS tells it to (usually the master hard drive on the first IDE channel, but this can also be checked for in CD/DVD drives and floppy drives) and, based on what the master boot record says, loads up an operating system. Thus, if the master boot record becomes corrupt or is tampered with by a virus, it can cause your computer to be unable to boot. |
| Boot Sector | The first sector of a bootable partition. It contains the information needed to start loading the operating system. |
| BootP | This protocol is the basis for DHCP. It allows a client computer to receive an IP address from a BootP server without having a static IP address defined beforehand on the client machine. |
| Bootstrap | This either refers to a small piece of intermediate code that will boot up an operating system, or the act of building something without help. See also Bootstrapping |
| Bootstrap Protocol | This protocol is the basis for DHCP. It allows a client computer to receive an IP address from a BootP server without having a static IP address defined beforehand on the client machine. |
| Bootstrapping | The process of developing something without reliance on outside help such as investor money. It's referred to often today, and often in the Dot-Com heyday, to describe website designers and entrepreneurs who effectively start their own companies on the Web with only their own investment. |
| Border Gateway Protocol | The protocol used by the core routers on the Internet to route TCP/IP packets. BGP replaces the older Exterior Gateway Protocol. Core routers use BGP exchange routing information to determine optimal routing paths and also exchange TCP/IP data packets. |
| Bottleneck | Part of a system that limits the performance of the system. This term was derived from the neck of a bottle, which limits the flow of liquid due to the smaller circumference of the neck as compared to the wider body of the bottle. Often you will hear of people attempting to find and eliminate the bottlenecks in their computer systems or networks. This is certainly a helpful practice if the bottleneck is slowing things down inordinately, but as soon as you remove one bottleneck from a system remember that something else immediately becomes the bottleneck. For example, if you get a faster processor to speed up your 3D video, the 3D video card may be the bottleneck afterwards. |
| Boxed Processor | A microprocessor that is sold singly in a retail box, like something you would buy at a store. This compares to just buying a processor that some OEM takes out of a bulk box of 1,000 processors and throws in a static bag for you to take home. Boxed processors typically come with multi-year warranties directly from the manufacturer. |
| Brick and Mortar | A store or business that either doesn't have a Web presence or has mainly physical locations as opposed to websites. Bricks and mortar are common building materials. |
| Broadcast | A method of sending information over a network. With broadcasting, data comes from one source and goes to all other connected sources. This has the side effect of congesting a medium or large network segment very quickly. Sometimes broadcasting is necessary to locate network resources, but once found, more advanced networking protocols change to point-to-point connections to transmit data. Nowadays, switches and routers often do not pass along broadcast packets, but in the days of shared Ethernet broadcasting could really congest a network. |
| BSOD | A Windows error message that is shown on a screen with a blue background. In Windows NT/2000/XP, this type of message causes the computer to stop completely, and is usually caused by improperly written hardware drivers or faulty hardware. Other BSODs can occur in different versions of Windows (95/98/Me) as well, but are not always as disastrous. Less frequently, black screens of death (also BSOD) are referred to as well during a complete system crash which may or may not have anything to do with the Windows OS. |
| Buffer | A temporary location to store or group information in hardware or software. Buffers are used whenever data is received in sizes that may be different than the ideal size for the hardware or software that uses the buffer. For example, a 64-bit processor on a 16-bit bus may have a buffer to hold 16-bit requests until they equal 64-bits. Another use of buffers is to keep hardware from getting overwhelmed with information. In that scenario, you use a large buffer to hold data until a device or program is ready to receive it, instead of just pushing it onto a device that might not be ready. Buffers must be optimized in size to work efficiently for the purpose they are designed. |
| Buffered memory | Memory modules that have extra chips on them to support Error Checking and Correcting (ECC) functionality. |
| Bug | This is commonly an error in design or programming in a hardware device or piece of software. The effects of a bug may be as harmless as an extra graphic on the screen, or as harmful as a system crash or loss of data. The first computer "bug" was a real bug, a moth, in fact, that was stuck between relays back in an early computer in 1945. See also Feature |
| Bulk Copy Program | A program used to copy databases or parts of databases in Sybase and Microsoft SQL Server environments. It was at first a command line program, but graphical interface programs have been put on top of it to make it more friendly. |
| Bulletin Board System | A bulletin board system used to describe message boards that people would dial into directly with modems before the Internet was easily accessible. Instead of dialing into a network where everything is connected, you had your choice of a group of BBSs to dial into, and each one tried to offer the most members, files, and graphics to its members. Typically you paid for access on a monthly basis. More recently, the term describes Internet-based message boards or forums. |
| Burn | Widely used slang that describes the creation of a CD-R disc. During the creation of a CD-R, a laser is used to burn tiny holes inside the disk media. |
| Burn in | The running of repetitive tasks on a computer to ensure that the computer is functioning properly. It also describes what can happen to older CRT screens when the same image is shown on them for long periods of time. An impression of the image is burnt into the screen, permanently damaging it. Screensavers were created to prevent this. |
| Burst EDO RAM | A type of EDO RAM that can read three consecutive memory locations in three clock cycles--a 1-1-1 burst. This makes BEDO RAM much faster at reading large blocks of data than standard EDO RAM. However, it cannot operate faster than 66MHz, limiting its applications in today's computers. Burst EDO was never more than a niche technology. |
| Bus mouse | A mouse that uses the smaller 6-pin connector instead of your computer's serial port. Also referred to as a PS/2 mouse because of its early adoption in the IBM PS/2 series of computers. |
| Bus speed | A measurement, usually in MHz, of how many times data can be transferred over the bus per second. |
| Bus Topology | This network topology has computers connected to a strand of network cabling that is connected to network repeaters at one end and terminated at the other. If you break part of the cable or remove the terminator, all machines on that segment lose communication with the network. 10Base2 was a widely used bus topology network in its day. |
| Business to Business | This term is often used to describe websites that sell goods or services to other businesses. Thus, businesses are serving other businesses as opposed to consumers. |
| Business to Consumer | A form of doing business that deals with selling goods and services to the consumer marketplace. Examples of this would be selling consumer electronics, toys, or pet supplies. This contrasts with the business to business model. |
| Bytes per second | This is generally a measure of how fast some device communicates, usually in thousands of bytes per second (KBps) or millions of bytes per second (MBps). See also bits per second. If you've got a capital B, you are talking Bytes, not bits. |
| C Sharp | An object-oriented programming language from Microsoft based on C/C++ that contains functionality similar to that found in the Java programming language. It is designed to work with Microsoft's .NET platform. |
| C# | An object-oriented programming language from Microsoft based on C/C++ that contains functionality similar to that found in the Java programming language. It is designed to work with Microsoft's .NET platform. |
| C++ | An extension of the C programming language that adds object-oriented concepts. |
| Cab file | A compressed file with the extension .cab. Cabinet files are used to store installation files for Microsoft applications, most commonly Windows 9x operating systems and Internet Explorer. Cab files were initially designed to fit large installations onto a group of 1.44 MB floppy disks. |
| Cabinet file | A compressed file with the extension .cab. Cabinet files are used to store installation files for Microsoft applications, most commonly Windows 9x operating systems and Internet Explorer. Cab files were initially designed to fit large installations onto a group of 1.44 MB floppy disks. |
| Cable Modem | The device that you attach a coaxial cable from your cable company directly into that can provide you with high speed Internet access. The cable modem typically has a port on it so that you can connect a network cable between it and your computer to connect you to the cable network. If your cable company supports such access, it is typically at 1.5-3.0Mbps, about 50-100 times faster than a 56K modem. |
| Cable Select | This is basically Plug-and-Play ATA. You plug in your ATA/IDE hard drives, set them to CSEL (Cable Select), and they determine whether they are master or slave automatically, saving you from manual configuration. |
| Cache memory | Generally a small chunk of fast memory that sits between either 1) a smaller, faster chunk of memory and a bigger, slower chunk of memory, or 2) a microprocessor and a bigger, slower chunk of memory. The purpose of cache memory is to provide a bridge from something that's comparatively very fast to something that's comparatively slow. Most microprocessors have built-in cache memory that holds some of the information from main memory. When the processor needs the information it takes it from the speedy cache instead of the slower main memory. Cache memory GREATLY increases the speed of a computer by storing data that is most often accessed. |
| CAD | Oh, you cad! This refers to the use of computers to design things. There are specific CAD programs like AutoCAD that are generally resource-intensive, requiring fast processors, lots of memory, and a big, clear monitor for best results. CAD has enabled people to easily model, create, and walk through or view designs of 3D objects or floor plans from different angles on a computer without actually taking the time to make a physical mock up. This is a huge time saver, and has revolutionized design in general. |
| Cannon Cable | An analog audio cable normally used to connect microphones to professional audio devices. It has three pins and provides a balanced input, as opposed to an unbalanced or single-ended RCA connector. |
| Capacitor | An electronic component that stores up an electrical charge to a certain level and then releases it. A capacitor stores energy between two conducting plates separated by an insulator, or dialectric. Capacitance, or the amount of current that is stored, is measured in farads. You may notice large looking electronic cylinders on your motherboard. These are capacitors, and they are used to provide clean power to your processor. You'll also find larger capacitors in your power supply. CRT televisions and monitors contain many capacitors, that's why you are warned against opening up a CRT device or power supply even when it is off, as there may still be electrical energy in the capacitors. |
| Carbon Copy | A method of sending a copy of an e-mail to someone, but implying that the person is not the direct recipient. For example, you send an e-mail with instructions to a group you manage, and CC it to your boss so that he or she knows what's going on but understands that the instructions in the mail were not meant for him or her to carry out. When you carbon copy someone in an e-mail, the recipients in the "To" field of the e-mail are aware of the names in the CC field. If you want to keep names secret from the To and CC recipients, you would use "BCC," or blind carbon copy. |
| Cardbus | The 32-bit PCMCIA card slot and cards that can work in this slot. Standard PCMCIA, or PC Card, slots were originally 16-bit slots. This caused problems when 100Mbit network cards and fast SCSI cards were used and throughput would not go high enough because the 16-bit slots were too slow. |
| CAS | see Column Address Strobe, CAS 2, and CAS 3 |
| CAS 2 | This implies that two clock cycles are needed to address a column of a memory chip. CAS 2 SDRAM memory is preferable to CAS 3 SDRAM memory, but is often more expensive. DDR memory has CAS 2 and CAS 2.5 for comparison. You can sometimes set the CAS latency of your memory in your computer BIOS. |
| CAS 3 | This implies that three clock cycles are needed to address a column on a memory chip. |
| CAS latency | see CAS 2 and CAS 3 |
| Cascading Style Sheets | You can use CSS to define one or more styles on a single Web page or group of Web pages. The styles determine how information is displayed in browsers. For example, you could define a style for text that sets the font to Arial and the size to 2, and use that style wherever it is appropriate on your HTML pages. A style can affect one page or a group of them. The vast majority of current browsers support CSS. |
| Cat 3 | Cat 3 cable is certified to run at up to 16MHz. You can achieve speeds of up to 10Mbps on Cat 3 cable. This cable maxes out with standard 10Mbps Ethernet. |
| Cat 4 | Cat 4 cable is certified to run at up to 20MHz. You can achieve speeds of up to 16Mbps, such as with the 16Mbps token-ring standard. |
| Cat 5 | This was a very common copper wire standard between 1996-2002 and today. It uses an RJ-45 plug and four-pair wire like Cat 3 and Cat 4, but it is certified to run up to 100MHz and is suitable for 100Mbps wiring standards. Higher speeds are possible, and some installers certify Cat 5 wire at 155Mbps or more. |
| Cat 5e | A copper wire cable standard that contains four twisted copper wire pairs, like earlier versions such as Cat 3, 4, and 5. It allows connection speeds of 400MHz. |
| Cat 6 | A cable standard for cable that contains four twisted copper wire pairs, just like earlier copper cable standards. It was designed with Gigabit Ethernet in mind, and typically allows transmission speeds of 400-550MHz. |
| Cat 7 | A cable standard for cable that contains four twisted copper wire pairs. It is not yet fully ratified. It typically allows transmission speeds of up to 600MHz. |
| Category 3 cable standard | Cat 3 cable is certified to run at up to 16MHz. You can achieve speeds of up to 10Mbps on Cat 3 cable. This cable maxes out with standard 10Mbps Ethernet. |
| Category 4 cable standard | Cat 4 cable is certified to run at up to 20MHz. You can achieve speeds of up to 16Mbps, such as with the 16Mbps token-ring standard. |
| Category 5 cable standard | This was a very common copper wire standard between 1996-2002 and today. It uses an RJ-45 plug and four-pair wire like Cat 3 and Cat 4, but it is certified to run up to 100MHz and is suitable for 100Mbps wiring standards. Higher speeds are possible, and some installers certify Cat 5 wire at 155Mbps or more. |
| Category 5e cable standard | A copper wire cable standard that contains four twisted copper wire pairs, like earlier versions such as Cat 3, 4, and 5. It allows connection speeds of 400MHz. |
| Category 6 cable standard | A cable standard for cable that contains four twisted copper wire pairs, just like earlier copper cable standards. It was designed with Gigabit Ethernet in mind, and typically allows transmission speeds of 400-550MHz. |
| Category 7 cable standard | A cable standard for cable that contains four twisted copper wire pairs. It is not yet fully ratified. It typically allows transmission speeds of up to 600MHz. |
| Cathode Ray Tube | One of the main components of most monitors and TVs. A beam of electrons is shot towards the CRT, and as the electrons collide with phosphors on the inside surface they produce light. Today, other technologies are performing better than the heavy and bulky tube monitors. LCD panels, gas plasma panels, and projection units are all in contention, but they still can't compare to the low cost of a CRT monitor or TV. |
| CAV | A method of reading (or writing) data from (or to) a spinning disk. As data is read from the disk, the drive motor always spins at the same speed. For example, CD- drives that work at CAV will read data at 12x towards the center, which has less space to record data, and 20x towards the larger data track on the edge, where the disk is moving faster. |
| CCD | Photosensitive CCDs are used in scanners, digital cameras, and video cameras. The CCD basically reads the image by storing a group of charges based on the image to which it is exposed. These charges are analog charges, as opposed to simple digital on/off charges. Thus, you can grab degrees of light and color to transfer a visual image into a group of electrical charges, and then to your computer screen, video tape, or printer. |
| CD-R | CD-R drives record up to 650 MB of data onto specialized CD-R media. The media is more expensive compared to the mass-produced CDs that software is generally distributed on, but cheap for the amount of data you can store on it. CD-R media is a WORM technology. You can Write to it Once and Read Many times, but you can't erase anything you've written. |
| CD-ROM | CD-ROM media is read-only media that holds about 650 MB of data. It's generally accepted as the easiest way to distribute software. CD-ROM drives can also read audio CDs even though they are in a different format than standard CD-ROM media. |
| CD-RW | A CD-ROM format that not only reads standard CD-ROMs, but can read and write CD-R disks, and also read and re-write CD-RW media. CD-RW media is more expensive than CD-R media, but it can be written to more than once in the same location, much like a hard drive or floppy disk on a computer. Standard CD-RW disks store up to 640 MB of data, similar to CD-ROM and CD-R disks. |
| CDMA | A 2G digital wireless technology that allows multiple calls to share a radio frequency 1.23MHz wide in the 800MHz-1.9GHz band without causing interference. This is accomplished by assigning each call a unique code and varying its signal by that code to allow only the caller and receiver with that code to communicate with each other. The original CDMA standard allows transmission of up to 14.4Kbps per channel, with up to 8 channels being able to be utilized at once for 115Kbps speeds. |
| CDMA2000 | The multiplexed version of the IMT-2000 standard developed by the ITU, and it's part of 3G wireless technology. It increases wireless data transmission speeds of the original CDMA standard to 144Kbps using a single channel and 2Mbps by utilizing 16 channels. |
| Cell | A coverage area around a specific transmitter that communicates with cellular telephones and enables phone calls to the same or other cells. If a cellular phone user is traveling while calling, he or she may be switched from transmitter to transmitter while moving from one cell to another. |
| Cellphone | A mobile, wireless telephone that communicates with a local transmitter using a short-wave analog or digital transmission. Cellular phone coverage is limited to areas where a cellular phone can adequately communicate with a nearby transmission tower. |
| Cellular Telephone | A mobile, wireless telephone that communicates with a local transmitter using a short-wave analog or digital transmission. Cellular phone coverage is limited to areas where a cellular phone can adequately communicate with a nearby transmission tower. |
| Central Processing Unit | Think of this as the brains of the computer. When most people think of processors, they think of Intel, AMD, Motorola, or IBM. The Pentium 4 and Athlon are popular CPUs. The CPU's first instruction is to check the system BIOS and do what the BIOS tells it. The CPU is designed to run a group of instructions, or instruction set. CPU instructions can consist of adding together numbers, subtracting, fetching information from memory, and numerous other simple functions. The computer's operating system feeds the CPU instructions after the BIOS locates the operating system and puts it into main memory. |
| Certificate Authority | A trusted third-party organization or company that issues digital certificates. The CA guarantees that the holder of the digital certificate is who he or she says he or she is. The issuing party typically confirms the information provided to it by credit card verification. |
| Certified Novell Administrator | The title of an individual who has passed tests on networking using Novell products. This certification is aimed at network administrators who oversee the day-to-day operations of maintaining Novell NetWare networks that are already installed. See also CNE. |
| Certified Novell Engineer | A certification similar to the CNA but requiring the passing of more tests. It is aimed at people interested in installing and planning the rollout of Novell NetWare- based networks, with day-to-day operations just a part of the certification. |
| CF+ | An extension to the CompactFlash standard that allows for use of devices other than plain storage Flash memory and microdrives. With CompactFlash+, devices such as CompactFlash network adapters and modems are now possible. |
| CFM | A measure of airflow, and you can use it to compare the efficiency of fans designed to cool computers or computer components. Higher CFM rates are better. |
| CGA | A video standard that allowed a resolution of 320x200 with a whopping four colors. It was replaced byEGA. You can get 16 colors on CGA if you go down to 160x100resolution. This is the first real graphics standard for IBM PC-compatible computers. |
| Chad | The piece of paper that is removed from a punch card when holes are punched into it. Problems with chads that don't punch through were seen quite a bit when punch cards were the main storage media of early computers, and then again in the U.S. presidential elections in 2000, where punch cards were used to register votes. |
| Channel | The group of resellers that supply most companies with software, hardware, and support. The channel is a force to be reckoned with, and it competes directly against, and works with, companies like Dell and IBM. A channel can also be a content container, like a television channel. |
| Channel Service Unit/Data Service Unit | A piece of hardware that you use to translate the digital data frames of a T1 line into a 10BaseT connection where Internet connectivity is concerned. If the T1 lines are used for voice connections, a CSU/DSU is required to translate the digital frames into signals that your office phone switch can interpret. Basically, the phone network/Internet consists of a bunch of CSU/DSUs talking to one another. When you lease a T1 line, your provider typically supplies you with a CSU/DSU, often with a setup cost. A synonym for CSU/DSU is DSU/CSU. |
| Character | A single letter, number, or symbol. This term applies to data typed into a computer, shown on computer screens, or printed (or written) on paper. |
| Characters Per Second | The amount of text characters printed in a second. This term was used more when daisy wheel and dot matrix printers were common. Nowadays, printers are rated more by pages per minute (ppm), as the amount of characters printed are irrelevant to modern printers that work on a page-by-page basis. Although inkjet printers still go line by line like dot matrix printers, they are much faster, and it's easier to compare page printing speeds. |
| Charge Coupled Device | Photosensitive CCDs are used in scanners, digital cameras, and video cameras. The CCD basically reads the image by storing a group of charges based on the image to which it is exposed. These charges are analog charges, as opposed to simple digital on/off charges. Thus, you can grab degrees of light and color to transfer a visual image into a group of electrical charges, and then to your computer screen, video tape, or printer. |
| Chassis | Pronounced "chassy," this is the frame or case which holds your computer components. |
| Chat room | Any Web address, IRC channel, or other virtual space where two or more users can get together and exchange synchronous remarks. Most chat rooms have a particular theme, but a theme is not required. |
| Checksum | A value that is calculated from a group of data and often passed along with the data when it is transferred. The receiver of the data will compare it to the checksum, and if it doesn't match the receiver knows the data was corrupted in transit. Checksums are used in all types of data communication, such as reading data from hard drives, CDs, floppies, modem communications, and networking. |
| Chief Information Officer | An executive title, usually at a medium or large-sized company. The person that bears this title is in charge of the flow of information in and out of the company, and also guides the technology used in information systems. The CIO's focus, as opposed to the CTO, is more on internal technology use and the IT department. A CIO is more concerned with keeping systems running day-to-day and uptime. CIOs are typically more managerial than CTOs. |
| Chief Technology Officer | An executive title related to CIO, usually at a medium or large-sized company. The CTO is, however, more focused on the use of technology in products developed by the company and technology delivered to external customers. CTOs are typically more technical than CIOs. |
| Chip | short for microchip. This term is commonly used to describe the CPU. More specifically, it refers to the part of the CPU that actually does the work, since many CPUs now contain L1 and L2 caches on-chip. |
| Chipkill | A technology developed by IBM for servers and other systems that demand high availability. It allows a computer motherboard and BIOS to detect problems with the computer's memory and selectively disable problematic parts of the memory. Depending on the technology used, this technology may or may not require specialized memory chips. |
| Chipset | The chips that control the functions and features on a motherboard. The chipset determines how much memory you can put into a motherboard and what processors you can use with it. Of course, there are physical connectors on your motherboard that limit these things as well, but motherboard manufacturers use the chipset as a basis for what type of connectors they can put on a motherboard. |
| chkdsk | A Microsoft program that checks your hard drive for logical errors as opposed to physical defects. This program is supported in DOS and all versions of Windows. Windows NT/2000/XP uses it as its main disk checking program. DOS and Windows replaced this program with the friendlier scandisk.exe, but chkdsk.exe is still available and is still the main disk checking program for NTFS partitions. |
| CICS | Not to be confused with CISC, CICS is online transaction processing application server software originally written by IBM for mainframes for dealing with customer information and transaction processing in the enterprise. Now versions of CICS are available for UNIX and x86 platforms as well. |
| CIO | An executive title, usually at a medium or large-sized company. The person that bears this title is in charge of the flow of information in and out of the company, and also guides the technology used in information systems. The CIO's focus, as opposed to the CTO, is more on internal technology use and the IT department. A CIO is more concerned with keeping systems running day-to-day and uptime. CIOs are typically more managerial than CTOs. |
| CIR | This term is used by ISPs to represent an amount of data that you should, on the average, be able to draw through your connection to the ISP's servers. This is measured in kilobits or megabits per second. |
| Circuit | Most commonly, this describes an electrical device with a defined path of electrical current that can receive input voltages in a 0 range and a 1 range, and responds with an output voltage that is also in a 0 or 1 range based on the logic inside of the circuit. If the circuit has a 0 range of 0-1 volts and a 1 range of 4-5 volts and receives a 0.5 volt input, it will act as if it has received a "0" input. Ranges are necessary because voltages are never exact. When thinking about the logic behind a circuit, it is easiest to think of the inputs and outputs simply as a 0 or 1 instead of a range of voltages. See also integrated circuit. |
| Circuit breaker | A device that interrupts the flow of electricity if an excessive level of current is detected. It's a better design than the fuse, as it can just be reset (instead of replaced) to turn the electrical flow back on. |
| CISC | Microchips that support a large amount of instructions of varying length. On the other side of the coin, you have RISC chips that use a smaller instruction set of more regular length. The battle between RISC and CISC rages on, but when it comes down to it, either way has its advantages and disadvantages. With CISC you can implement often-used strings of instructions into single instructions that could give you an advantage over the numerous small instructions used in RISC. However, the unpredictability of the length of a CISC instruction typically limits CISC from blowing RISC away. |
| Class A IP | A group of IP addresses where the first number remains the same, and the last three can vary. It could be represented by w.x.y.z, where the x, y, and z can be any number from 0-255, and the w represents the first static part of the IP address (e.g., 10.x.y.z). Thus, the number of possible combinations within the Class A address are 256*256*256 = 16,777,216. Of course, some of the addresses, like those ending in .0 and .255, are not used, so the actual number of usable addresses in a Class A is somewhat less than that. The subnet mask of a class A IP address is 255.0.0.0. Thus, only the last three digits of the IP address are used to determine where traffic gets routed within the Class A. There are 254 class A groups in existence. |
| Class B IP | A group of IP addresses where the first two numbers remain the same and the last two can vary. It could be represented by w.x.y.z, where the y and z can be any number from 0-255, and the w and x represent the first static part of the IP address (e.g., 10.251.y.z). Thus, the number of possible combinations within the Class B address are 256*256 = 65,536. Of course, some of the addresses, like those ending in .0 and .255, are not used, so the actual number of usable addresses in a Class B is somewhat less than that. The subnet mask of a class B IP address is 255.255.0.0. Thus, only the last two digits of the IP address are used to determine where traffic gets routed within the Class B. There are about 65,000 class B groups in existence. |
| Class C IP | A group of IP addresses where the first three numbers remain the same and the last one can vary. It could be represented by w.x.y.z, where the z can be any number from 0-255, and the w, x, and y represent the first static part of the IP address (e.g., 10.251.37.z). Thus, the number of possible combinations is 256. Of course, some of the addresses, like those ending in .0 and .255, are not used, so the actual number of usable addresses in a Class C is 254. The subnet mask of a class C IP address is 255.255.255.0. Thus, only the last digit of the IP address is used to determine where traffic gets routed within the Class C. There are about 16.7 million class C groups in existence. |
| Client/Server | Client server technology came about when computers began to cost less. Mainframes are very expensive, and didn't give users much personal freedom. The client/server model promised to change that scenario, and it's much more popular today. Basically, a client computer with its own memory and hard drive communicates with a server whenever it needs data from the server. The client can run by itself without the server and communicate with different servers as it needs to. |
| Clip Art | Graphics/artwork distributed for use in word processors, Web pages, or desktop publishing. Graphic designers often use clip art as a shortcut to developing images from scratch. Some clip art is in the public domain, but much of it is copyrighted and restricted to certain uses. Take care to understand the copyright, or lack thereof, when you use clip art. |
| Clock chipping | Synonym for overclocking. |
| Clock Cycle | Think of a clock cycle as one tick of the second hand (but generally at a much higher speed). Computer clocks run voltage through a tiny crystal that oscillates at a predictable speed to give a meaningful timing method to the computer. One clock cycle doesn't necessarily mean that the processor does one operation. Today's high-end processors often complete more than one operation per clock cycle, and other times, in the worst cases, it will take several clock cycles to complete one operation. |
| Clock Speed | The speed in MHz of a microprocessor. It is one way of gauging the performance of a microprocessor; however, different processor architectures dictate that a higher clock speed in one architecture does not always mean better performance over a lower clock speed in another architecture. |
| Cluster | A group of computers connected over a network that are running software that allows them each to work on individual pieces of one greater task. |
| Clustering | Clustering is a technology using two or more computers that function together as a single entity for fault tolerance and load balancing. This can increase reliability and uptime in a client/server environment. One computer will sense when another computer is failing or getting bogged down and will take over full operation or just some of its tasks, depending on whether it's a complete fail-over design or just load balancing. |
| CLV | In terms of disk drives, this means that the rate of data being read off of the disk stays the same from center to outer edge. To accomplish this, the drive motor speeds up and slows down as data is read from different areas of the disk--the linear velocity remains constant. An 8x CD-ROM drive that operates at CLV will read data at 8x anywhere on the disk, from the center to the outer edge. That means that data is written closer together towards the center of the disk and further apart towards the edge. |
| CMOS | A method of constructing transistors which produces microchips that run with relatively low power consumption compared to other methods. Most of the chips found in a modern PC are built using CMOS technology. |
| CMYK | An alternate color scheme to the RGB color scheme. Combinations of cyan, magenta, yellow, and black are used to represent colors. The CMYK scheme is used mainly in print, such as magazines. Combining cyan, magenta, and yellow produces black, but that black is not always pure enough, thus, the addition of the K, for pure black. Color inkjet printers use CMYK to represent images. The best printers have separate black instead of wasting all the colors to print a faux brownish black. |
| CNA | The title of an individual who has passed tests on networking using Novell products. This certification is aimed at network administrators who oversee the day-to-day operations of maintaining Novell NetWare networks that are already installed. See also CNE. |
| CNE | A certification similar to the CNA but requiring the passing of more tests. It is aimed at people interested in installing and planning the rollout of Novell NetWare- based networks, with day-to-day operations just a part of the certification. |
| Co-Location | The practice of having your webservers, or other servers, hosted at another location by another company. Often, companies will co-locate their webservers at an ISP that handles the bandwidth, power, cooling, and, to varying degrees, the care and maintenance of the webservers. |
| Coaxial cable | The type of cable used by the 10Base2 Ethernet standard, and also in most home cable television. It consists of a single, insulated copper wire, surrounded by a copper braid or foil that acts as a ground. The entire wire is then coated with plastic. |
| COBOL | A programming language developed in the '60s by several computer companies and the U.S. Department of Defense. COBOL is still used today for programming business applications, and COBOL programmers were a major source of the Year 2000 headache. In fact, many of them came out of retirement to fix the mess they made, whether voluntarily or by direction, to save a couple of valuable bits of data back when bits cost big money. |
| Code | A series of instructions that make up a program. |
| Code Division Multiple Access | A 2G digital wireless technology that allows multiple calls to share a radio frequency 1.23MHz wide in the 800MHz-1.9GHz band without causing interference. This is accomplished by assigning each call a unique code and varying its signal by that code to allow only the caller and receiver with that code to communicate with each other. The original CDMA standard allows transmission of up to 14.4Kbps per channel, with up to 8 channels being able to be utilized at once for 115Kbps speeds. |
| Code generator | A code generator is part of a compiler. It takes intermediate code and translates it into the final workable code in the target language. |
| Codec | Codecs are standard methods of coding and decoding data. Typically, the data is coded and/or compressed to save space. Usually, this is done with multimedia data such as video and audio. A codec allows an operating system or a program to properly play audio or video in a particular format. |
| Coily | Enemy of Q-Bert. |
| ColdFusion | A server side extension developed by Allaire that allows documents similar to HTML, usually with the .cfm extension, to be parsed and run on a webserver. ColdFusion allows Web designers to embed database calls into HTML-like documents, and is designed to provide easier access to database servers than by using standard CGI calls. |
| Collision | What happens on a piece of networking equipment, usually a shared hub, that is being asked to transfer more data than it can handle. Collisions occur when a client on the network tries to transfer data and has to retry because the device is busy and the data figuratively "collides" with other data on the network. |
| Colo | Short for co-location. |
| Column Address Strobe | An electrical signal that determines which column is read or written to on a DRAM chip. You must combine a column address strobe with a row address strobe to define a location on a DRAM chip. |
| COM Port | An abbreviation for communications port, this generally refers to a serial port. |
| Comma Separated Values | A file extension used for a flat text data file consisting of items of data separated by commas. Each line of data is separated by a carriage return. |
| Command Prompt | Any blinking cursor waiting, or prompting, for user input. In DOS the C: prompt greets you on most systems--this is a type of command prompt. As well, if you use any version of Windows you can get to a DOS-looking window that allows you to type in commands. UNIX can also greet you with a command prompt. For novice users a command prompt can be confusing, as it's unclear what to do next; but for experts a command prompt is a necessity at times. |
| Committed Information Rate | This term is used by ISPs to represent an amount of data that you should, on the average, be able to draw through your connection to the ISP's servers. This is measured in kilobits or megabits per second. |
| COmmon Business-Oriented Language | A programming language developed in the '60s by several computer companies and the U.S. Department of Defense. COBOL is still used today for programming business applications, and COBOL programmers were a major source of the Year 2000 headache. In fact, many of them came out of retirement to fix the mess they made, whether voluntarily or by direction, to save a couple of valuable bits of data back when bits cost big money. |
| Common Gateway Interface | This interface allows scripts or programs to run on a webserver. Most webservers support CGI scripting. You can make a CGI script do pretty much anything a computer program can. Most commonly, they are implemented to control user interaction with the webserver on a website. You can use CGI scripts to save a user survey to a file on the server or to display dynamic data to a user. |
| Common Object Request Broker Architecture | A standard that allows programs or objects to communicate even though they may have been written by different vendors. CORBA is defined by a group of 800 companies called the Object Management Group, a non-profit consortium that produces and maintains computer industry specifications for interoperable enterprise applications. Microsoft has been a member of OMG since 1992 and has released competing technologies, first with OLE and more recently with DCOM. |
| Compact Disc Read Only Media | CD-ROM media is read-only media that holds about 650 MB of data. It's generally accepted as the easiest way to distribute software. CD-ROM drives can also read audio CDs even though they are in a different format than standard CD-ROM media. |
| Compact Disc Recordable | CD-R drives record up to 650 MB of data onto specialized CD-R media. The media is more expensive compared to the mass-produced CDs that software is generally distributed on, but cheap for the amount of data you can store on it. CD-R media is a WORM technology. You can Write to it Once and Read Many times, but you can't erase anything you've written. |
| CompactFlash | A 50-pin connection standard used in some PDAs, digital cameras, hardware MP3 players, and other small hardware devices. It was initially designed to offer PCMCIA-ATA standard access to Flash memory in a smaller form factor than PCMCIA at 43 mm by 36 mm and thicknesses of 3.3 mm (Type I) or 5.5 mm (Type II), but the standard has been expanded to support other peripherals, such as CF modems, CF network cards, and other types of I/O devices with the CompactFlash+ standard. |
| CompactFlash+ | An extension to the CompactFlash standard that allows for use of devices other than plain storage Flash memory and microdrives. With CompactFlash+, devices such as CompactFlash network adapters and modems are now possible. |
| Competitive Local Exchange Carrier | The Telecommunications Act of 1996 sought to create this type of service company that would offer local calling, long distance, international calling, and Internet access. The CLECs would compete with the incumbent local exchange carrier (then Bell Atlantic) by leasing their local loops and creating their own on which to sell services. |
| Compiler | A compiler translates a computer program from one language into another, catching any errors in syntax along the way.Most commonly, you translate some high level language, such as C++ or COBOL, into optimized machine language. This form of compilation puts your programs into a form that your computer (specifically your microprocessor) can understand without any translation, thus speeding them up greatly over programs that must be interpreted as they are run. |
| Complementary Metal-Oxide Semiconductor | A method of constructing transistors which produces microchips that run with relatively low power consumption compared to other methods. Most of the chips found in a modern PC are built using CMOS technology. |
| Complex Instruction Set Computer | Microchips that support a large amount of instructions of varying length. On the other side of the coin, you have RISC chips that use a smaller instruction set of more regular length. The battle between RISC and CISC rages on, but when it comes down to it, either way has its advantages and disadvantages. With CISC you can implement often-used strings of instructions into single instructions that could give you an advantage over the numerous small instructions used in RISC. However, the unpredictability of the length of a CISC instruction typically limits CISC from blowing RISC away. |
| Component Object Model | A Microsoft specification that describes methods of communication between components. For example, if you were to drag an item over a window, the item and window would have some rules of communication that they would follow. Those rules are described in the Component Object Model. |
| Computer | Simply put, this is anything that inputs data, processes it in some way, and outputs it. |
| Computer Aided Design | Oh, you cad! This refers to the use of computers to design things. There are specific CAD programs like AutoCAD that are generally resource-intensive, requiring fast processors, lots of memory, and a big, clear monitor for best results. CAD has enabled people to easily model, create, and walk through or view designs of 3D objects or floor plans from different angles on a computer without actually taking the time to make a physical mock up. This is a huge time saver, and has revolutionized design in general. |
| Computer Graphics Adapter | A video standard that allowed a resolution of 320x200 with a whopping four colors. It was replaced byEGA. You can get 16 colors on CGA if you go down to 160x100resolution. This is the first real graphics standard for IBM PC-compatible computers. |
| Computer model | A computer model is a recreation of a static scene, be it a house or a complex CAD design. |
| Computer simulation | A prediction of the outcome of events by using actual data and attempting to mimic the environment on a computer. Computer simulations are used often in predicting the weather. |
| Computer Telephony Integration | Simply put, this represents the integration of a computer and telephone. Its serious uses include phone registration, fax-back systems, and other systems that record or supply information by simple touch-tone telephone access. A basic use of this technology would be using your computer/modem as an auto- dialer so you don't have to push the buttons on your phone. |
| Conditional Statement | In programming, this is a type of command that controls the flow of a program based on whether certain conditions are met. The statement is normally set up in the form: IF (specific condition is met) THEN (do this action) ELSE (do this if the condition is not met). The "Else" statement or condition does not usually have to be listed specifically. It can be implied that if there is no type of Else statement then program flow continues normally if the condition is not met. Conditions can range from simple (x equals 3) to more complex conditions (x is not less than or equal to the number of characters in a string). |
| Console | This term can be used generally to describe a computer, a terminal, or, more recently, a dedicated gaming system. |
| Console Game | A game designed to be played on a game console. |
| Constant Angular Velocity | A method of reading (or writing) data from (or to) a spinning disk. As data is read from the disk, the drive motor always spins at the same speed. For example, CD- drives that work at CAV will read data at 12x towards the center, which has less space to record data, and 20x towards the larger data track on the edge, where the disk is moving faster. |
| Constant Linear Velocity | In terms of disk drives, this means that the rate of data being read off of the disk stays the same from center to outer edge. To accomplish this, the drive motor speeds up and slows down as data is read from different areas of the disk--the linear velocity remains constant. An 8x CD-ROM drive that operates at CLV will read data at 8x anywhere on the disk, from the center to the outer edge. That means that data is written closer together towards the center of the disk and further apart towards the edge. |
| Content Scrambling System | This is a method of scrambling DVD movie content so that DVD movies will not be played on unlicensed DVD player hardware. CSS is part of a complex group of technologies, including Macrovision and DVD Region control, developed to attempt to control the viewing and copying of DVD movies. A side effect of CSS is that no DVD movie playing software was developed for Linux, and thus the DeCSS program was created--its legality is still being fought out in the court systems in various countries. |
| Contrast Ratio | This ratio is equivalent to the brightness of the white level divided by the brightness of the black level of a display. A higher contrast ratio makes it easier to distinguish dark colors from one another. Early LCD screens had low contrast ratios compared to CRT monitors and were criticized for this, as many 3D games involved skulking about dark areas where contrast made a huge difference in seeing what was going on. |
| Control Program for Microprocessors | CP/M was THE operating system before IBM created the PC. IBM was shopping for an OS for the PC, ended up going with Microsoft, and Bill Gates created DOS. CP/M is not really used on anything but fossils at this point. |
| Convergence | The ability of the three electron beams (red, green, and blue) in a CRT monitor to meet at a single point and produce one dot. If a monitor is mis-converging, you will notice shadows of blue or red around any white images. Often, this will occur in only some parts of the screen. Some CRT monitors have convergence controls, but most do not, making it impossible to correct this condition without opening it up, which isn't a good idea due to how CRT monitors hold electrical energy. |
| Copper Barrier | An assumption that limits the amount of data that can be sent through a single copper wire as used in DVI connections, and thus why there are two types of DVI wiring. The assumed limit was approximately 165MHz when the DVI standard was put together. |
| CORBA | A standard that allows programs or objects to communicate even though they may have been written by different vendors. CORBA is defined by a group of 800 companies called the Object Management Group, a non-profit consortium that produces and maintains computer industry specifications for interoperable enterprise applications. Microsoft has been a member of OMG since 1992 and has released competing technologies, first with OLE and more recently with DCOM. |
| Core | In UNIX systems this term is commonly used in reference to memory, and the crash dump "core" files you will find if you do something naughty in UNIX. The term goes back to when memory chips were actually magnetic coils, or core memory. Yeah, I want my enterprise systems running on that! Just kidding, real core memory hasn't been built into systems in many, many years. |
| Core Dump | In UNIX systems, when a program crashes it "dumps" out an image of the memory and registers so that you may go through and see what caused the problem. This is almost as useful as the Netware and Windows NT memory dumps (which is not very, if you can't taste my sarcasm). The problem is that if you really have to know what's going on at a low level, you won't understand the dump--not many people can do that. However, if the problem is important enough and persistent enough, the dump gives knowledgeable developers/admins something to look at in order to try to fix the bugs in the system. |
| CP/M | CP/M was THE operating system before IBM created the PC. IBM was shopping for an OS for the PC, ended up going with Microsoft, and Bill Gates created DOS. CP/M is not really used on anything but fossils at this point. |
| CPM | This term is used when buying and selling Internet advertising banners, buttons, or text ads. CPM refers to the cost of displaying an ad impression 1,000 times. Buyers and sellers will typically list costs between US$0.20-$100 CPM, depending on how targeted the traffic is. The "M" refers to the Roman Numeral for thousand. |
| CPS | The amount of text characters printed in a second. This term was used more when daisy wheel and dot matrix printers were common. Nowadays, printers are rated more by pages per minute (ppm), as the amount of characters printed are irrelevant to modern printers that work on a page-by-page basis. Although inkjet printers still go line by line like dot matrix printers, they are much faster, and it's easier to compare page printing speeds. |
| CPU | Think of this as the brains of the computer. When most people think of processors, they think of Intel, AMD, Motorola, or IBM. The Pentium 4 and Athlon are popular CPUs. The CPU's first instruction is to check the system BIOS and do what the BIOS tells it. The CPU is designed to run a group of instructions, or instruction set. CPU instructions can consist of adding together numbers, subtracting, fetching information from memory, and numerous other simple functions. The computer's operating system feeds the CPU instructions after the BIOS locates the operating system and puts it into main memory. |
| CPU Terminator | A card that ensures that electrical signals on a CPU bus are terminated properly in multiprocessor systems where not all CPU slots are filled with CPUs. Some multiprocessor systems require that all processor slots be full so that the processor bus is terminated properly. If you have a four-processor system but only one processor, you will need three CPU terminators to ensure proper bus termination. |
| CRM | A class of enterprise software that enables a large company to manage all contact (or "touches") that it has with its customers. It would track, for example, calls to tech support, faxes, e-mails, direct mail, telephone contacts, and any other contact that a company would have with a customer and vice-versa. This information can be used for analysis of customer relationships, and gives salespeople an understanding of what to say when calling up a customer. |
| Cron | A UNIX/Linux daemon that allows tasks to be scheduled on a regular basis. The crontab command is used to schedule and view jobs. |
| Crontab | A UNIX/Linux command that allows you to view (crontab -l) or make changes (crontab -e) to the list of jobs scheduled to be run by the cron daemon. |
| Cross Platform | A term given to software that can be used on multiple hardware platforms, such as the x86 PC, the Macintosh, or Sun's Solaris systems. One such piece of software is Java. |
| Crossover Cable | An Ethernet cable using RJ-45 connectors, where one end of the cable has the order of the second two pairs of the 8 wires (green and orange) swapped. Instead of wires 1, 2, 3, and 6 going straight through, you have 1 going to 3, 2 going to 6, 3 going to 1, and 6 going to 2. (Thanks to DN for pointing that out.) You can use a crossover cable to directly connect two 10BaseT or 100BaseT network cards, basically making a network of two computers for easy file transfer or configuration of network printers or other devices. As well, crossover cables are often used to connect 10BaseT and 100BaseT hubs together. |
| CRT | One of the main components of most monitors and TVs. A beam of electrons is shot towards the CRT, and as the electrons collide with phosphors on the inside surface they produce light. Today, other technologies are performing better than the heavy and bulky tube monitors. LCD panels, gas plasma panels, and projection units are all in contention, but they still can't compare to the low cost of a CRT monitor or TV. |
| Crypto | The study of decryption and encryption technologies. |
| Cryptography | The study of decryption and encryption technologies. |
| Csel | This is basically Plug-and-Play ATA. You plug in your ATA/IDE hard drives, set them to CSEL (Cable Select), and they determine whether they are master or slave automatically, saving you from manual configuration. |
| CSU/DSU | A piece of hardware that you use to translate the digital data frames of a T1 line into a 10BaseT connection where Internet connectivity is concerned. If the T1 lines are used for voice connections, a CSU/DSU is required to translate the digital frames into signals that your office phone switch can interpret. Basically, the phone network/Internet consists of a bunch of CSU/DSUs talking to one another. When you lease a T1 line, your provider typically supplies you with a CSU/DSU, often with a setup cost. A synonym for CSU/DSU is DSU/CSU. |
| CSV | A file extension used for a flat text data file consisting of items of data separated by commas. Each line of data is separated by a carriage return. |
| CTI | Simply put, this represents the integration of a computer and telephone. Its serious uses include phone registration, fax-back systems, and other systems that record or supply information by simple touch-tone telephone access. A basic use of this technology would be using your computer/modem as an auto- dialer so you don't have to push the buttons on your phone. |
| CTO | An executive title related to CIO, usually at a medium or large-sized company. The CTO is, however, more focused on the use of technology in products developed by the company and technology delivered to external customers. CTOs are typically more technical than CIOs. |
| Ctrl | A key on a computer keyboard that typically adds 64 bits to the ASCII value of a key being pressed. Based on the program that is running, it can have different effects. It was added to create more key combinations besides just using the Shift key. In selection of items, holding down the Ctrl key will typically allow you to select or de-select a single item from a group without affecting the rest of your selection. |
| Cursor | This is often represented by a blinking line or square on your computer screen. The cursor is there to let you know where information will be displayed when you type on a keyboard. Many program manuals make reference to the cursor and describe where it should be placed so that you can enter information into software properly. You can use the pointer to place the cursor. |
| Customer Information Control System | Not to be confused with CISC, CICS is online transaction processing application server software originally written by IBM for mainframes for dealing with customer information and transaction processing in the enterprise. Now versions of CICS are available for UNIX and x86 platforms as well. |
| Customer Relationship Management | A class of enterprise software that enables a large company to manage all contact (or "touches") that it has with its customers. It would track, for example, calls to tech support, faxes, e-mails, direct mail, telephone contacts, and any other contact that a company would have with a customer and vice-versa. This information can be used for analysis of customer relationships, and gives salespeople an understanding of what to say when calling up a customer. |
| CXT Core | AMD added a feature to its K6-2 processor, running at 400MHz, called write combining, that queues up memory requests until there is a sufficient amount to fill the bus. So, AMD refers to processors with this technology as having the CXT Core. |
| Cyborg | A person who is partially flesh and bone, but has one or more robotic appendages electronically linked to his or her nerves. Often, a cyborg is said to be half human and half machine. For example, the "Terminator" character is a robot covered with human tissue--this is not a true cyborg. As well, a human with an artificial limb that is removable is not a cyborg. For a true cyborg it is hard to tell internally where the human ends and the robotic parts begin, and hard to separate one from the other. The Borg characters from Star Trek could be said to be true cyborgs, as they have a series of implants that truly merge flesh and machine (Robocop as well). |
| Cyclic Redundancy Check | A test to see whether data has been transferred properly over a modem or to and from disk media. The sender of the data adds a check number to the end of the data being sent, and the receiver applies the same check to the data and compares the number it gets with the check number. If they don't match, the data can be requested again. |
| Cylinder | This term is somewhat synonymous with the tracks on a hard disk drive. However, instead of a single track, a cylinder refers to the location of all the drive read and write heads, typically accessing multiple platters. Thus, when these tracks are mentally pictured, they are stacked up like a cylinder. Since all the heads are locked together, a specific cylinder number is equivalent to a track number on a specific platter, but refers to all platters at once. Got it? Whew. |
| DAC | An electronic device that converts digital signals into analog signals. You can find DACs in a variety of devices, including sound cards. The DAC would be used to convert digital signals from your computer into analog signals that can be sent to your speakers--assuming you use standard analog speakers. |
| Daemon | A term mainly used regarding UNIX processes. A daemon (or demon) is a process that starts and does nothing until it is called by another process or a certain condition is met. This is similar to a TSR program. |
| Daisy Chain | In computer terminology, this refers to connecting one device (historically SCSI, but now USB or FireWire as well) to another device, instead of directly to a computer. In fact, you can daisy chain several SCSI devices to one another, and only one of them needs to be connected to a computer with a SCSI interface for them all to be controlled by it. |
| Daisy Wheel printer | A printer that uses a wheel with all the characters on it to produce output. The wheel spins to the desired character and makes an imprint, then spins to go to the next character. It sounds like a little machine gun. These printers generally aren't used much anymore due to the decreased cost of other printers that can produce graphics as well as text. The one good thing about a daisy-wheel printer is that the text is generally very crisp, but even that advantage is nullified now with laser printers that can produce very crisp characters as well. |
| DAO | This is a single-session method of writing data to a CD-R/RW disc that creates a disc in a format suitable for commercial duplication. Basically, the entire disc is written at once in contrast to Track at Once. |
| Dark Fiber | Fiber optic wiring that has been installed but has not been turned on yet. Often, companies that lay fiber optic cabling will lay extra cable, since the laying of miles of cable is a very costly and time consuming procedure. This dark fiber will lay dormant until the company needs extra capacity, or until it leases it to another company that needs the capacity. Then the company "lights it up" by sending optical data over the fiber. |
| DAT | This type of magnetic tape, introduced by Sony, at one point threatened to supplant the normal audio cassette with a better quality alternative. Unfortunately, it never really took off due to foolish licensing issues that kept its price very high.However, the small tapes took off big in the computer industry. You can get DAT drives today that hold up to 40 GB of data compressed with DDS-4. Audio DAT tapes are not compatible with data drives. |
| Data | Information. Any series of bits, characters, or objects that has meaning. Data is stored and transmitted by computers. |
| Data Center | Any computing environment where there is a service agreement between the people managing the computing resources and the users. A company computer network is a data center, but so is a network at an ISP. Additionally, data center has come to mean a website or network with its resources dedicated to providing information on a particular subject. |
| Data Compression | Takes something large and makes it smaller. Compression generally comes in two forms: lossy and lossless. Lossy compression is best used on graphics files and sound files, where loss of quality is acceptable in many situations. Lossy compression crunches down the data at a much higher ratio, at the expense of having an image or a sound that isn't quite the same as before it was compressed. In the best scenario the data takes up less space, but the person viewing the graphic or listening to the sound file will not be able to notice. Lossless compression squeezes data down so that at some later date it can be uncompressed and returned to its exact structure. Lossless compression is best used on data files and programs. |
| Data Encryption Standard | An encryption method developed by IBM in 1977. It uses a private 56-bit key that is applied to each 64- bit block of data. The sender and receiver must each know the private key. Anything encrypted by DES encryption has 72,000,000,000,000,000 (or 72 quadrillion) possible keys. DES encryption has been broken, but it took over 14,000 computers operating in succession to crank through codes until the proper key was found. See also Triple DES encryption. |
| Data Entry | A job function where the employee is expected to enter data into a computer. Typically, the only technical skill you need for such jobs is typing. Some people use data entry positions to springboard into low-end technical support and head on towards more technical jobs. |
| Data Mining | The act of analyzing a database or data warehouse and searching for new facts based on the data. For example a supermarket may mine its customer data and find that 87% of people who buy tuna in a can also buy orange juice at the same time. Typically you mine data for meaningful relationships that you can exploit in business. |
| Data type | The type of data that is being used in a computer program. Different types of data take up different amounts of space. Some common data types are integer, float (for floating point numbers), or string (for a text string). If a procedure is expecting one data type and it gets another, you could get an error message or a crash, but that depends specifically on the programming language being used. |
| Data Warehouse | A large database where information is gathered from various online transaction systems. Usually, this information is put together and "mined," as in datamining, to learn more about customers or customer purchasing habits. Data warehouses are used to gather information that may not be obvious when viewed in one context, but when grouped together in the data warehouse and properly queried, you can find out useful information. For example, a supermarket may find out that 47% of its customers buy light bulbs at the same time that they purchase shoelaces. Some of this data may be useful in a business sense, and some of it not so useful. |
| Data Warehousing | The act of putting data together in a Data Warehouse. |
| DataBase Administrator | A person whose job it is to manage databases. A DBA's tasks may include assigning security privileges to the databases, creating and designing databases, and controlling the importing and exporting of data between databases and external sources. The creation and design of databases is a science. You can increase or decrease performance greatly by designing a database properly or improperly. |
| Daughter Board | A circuit board that plugs into a larger circuit board, or motherboard. Often processors are contained on daughterboards, along with cache memory. For example, Intel's Pentium II (and pre-FC-PGA Pentium III) processors shipped on a daughter board that plugs into the Slot 1 on the motherboard. |
| Daughter Card | A circuit board that plugs into a larger circuit board, or motherboard. Often processors are contained on daughterboards, along with cache memory. For example, Intel's Pentium II (and pre-FC-PGA Pentium III) processors shipped on a daughter board that plugs into the Slot 1 on the motherboard. |
| DB-25 | The name for the connector used for parallel ports on PCs. It has 25 pins, as you would expect. |
| DBA | A person whose job it is to manage databases. A DBA's tasks may include assigning security privileges to the databases, creating and designing databases, and controlling the importing and exporting of data between databases and external sources. The creation and design of databases is a science. You can increase or decrease performance greatly by designing a database properly or improperly. |
| DCOM | Yet another Microsoft technology. It is a version of the COM that is designed to work across networks and, specifically, the Internet. |
| DDE | A method of exchanging data between applications on MacOS, Windows, and OS/2 operating systems. DDE is similar to OLE, but predates it. It enables multiple applications to have access to the same data, such as a word processor having data from a spreadsheet pasted into it. Changes made in either application to the data are reflected in the main document. |
| DDR II SDRAM | A standard that is used to boost conventional SDRAM memory up to speeds of 200MHz and beyond.Standard SDRAM tops out around 150-166MHz, and DDR SDRAM starts at 200MHz by effectively doubling the speed of 100MHz SDRAM by sending two bits of data per clock cycle. A new standard called DDR II will push DDR SDRAM over 400MHz effective speeds, where standard DDR trails off. |
| DDR SDRAM | A standard that is used to boost conventional SDRAM memory up to speeds of 200MHz and beyond.Standard SDRAM tops out around 150-166MHz, and DDR SDRAM starts at 200MHz by effectively doubling the speed of 100MHz SDRAM by sending two bits of data per clock cycle. A new standard called DDR II will push DDR SDRAM over 400MHz effective speeds, where standard DDR trails off. |
| DDS | A storage standard used with medium cost tape media and tape drives, used mainly for small businesses and departmental backups. DDS tapes are the same size and form factor as DAT tapes used to store music digitally on tape media, but DDS media is more robust and more expensive. There are four different DDS standards: DDS-1 through DDS-4. The four standards allow for backup of 2 GB, 4 GB, 12 GB, and 20 GB worth of uncompressed (native) storage respectively. Storage sizes are typically listed as double for compressed data. DDS media is good for up to 10 years, but should not be used for more than 100 backups or it may become unreliable. DDS tapes are falling to the wayside as DLT, AIT, and other standards offer higher reliability. Sony and HP have both announced that they will not be supporting DDS-5, which pushes DDS data storage up to 40 GB of native storage per tape. |
| Debug | The act of diagnosing, fixing, or removing bugs from a computer programs. It can also be used to describe the fixing of bugs in HTML or other computer-based texts that are not necessarily programs. The first computer "bug" was an actual moth, and debugging that computer involved physically removing the moth from the system, as it was impeding electrical flow. |
| Debugger | A program that searches other programs for bugs. In addition to identifying definite or possible bugs, debuggers can usually step through programs one operation at a time. Debuggers are associated with a particular programming language, and are typically packaged as part of a programming language or set of programming tools. |
| Decibel | A logarithmic measure of sound intensity. It is equal to 10 times the common logarithm of the ratio of sound intensity to a reference intensity. A rating of 85 dB is loud, and prolonged exposure to those sound levels could damage hearing. |
| Decrypt | The act of decoding data that has been encrypted. |
| Decryption | The act of decoding encrypted data so that it can be understood. |
| DeCSS | A program that was developed to allow Linux to read DVD movies scrambled with the Content Scrambling System. The writers of the program reverse engineered the CSS scrambling method that the MPAA (Motion Picture Association of America) uses to prevent playing of DVD movies on unlicensed DVD players. DeCSS also allows DVD data to be decoded and translated into other formats. However, you can copy DVD movies without using DeCSS, as DVD content does not have to be decoded to be copied. |
| Dedicated Line | Often used to mean a telephone line used solely for your computer modem or fax machine, and not used for voice calls--although it technically could be. |
| Default | The fallback value. If nothing else is specified the default value will be used. If you install a program it generally installs with the default settings unless you override the pre-programmed settings with your preferences. |
| Defrag | Slang for the act of defragmenting a hard drive. When you defragment a hard drive you use a software utility to arrange the order of your files so that each file is represented in a physically continuous segment. Defragmentation can improve your hard drive performance because it can read any particular file in a continuous stream instead of jumping here and there around a hard drive to locate each file segment or fragment. See also fragmentation. |
| Defragment | When you defragment a hard drive you use a software utility to arrange the order of your files so that each file is represented in a physically continuous segment. Defragmentation can improve your hard drive performance because it can read any particular file in a continuous stream instead of jumping here and there around a hard drive to locate each file segment or fragment. See also fragmentation. |
| Degauss | The act of de-magnetizing a CRT monitor or magnetic media. Degaussing a CRT monitor is necessary when a monitor has been moved in relation to the Earth's magnetic fields (around your office or living room). This can cause a build-up of magnetism which distorts the color or clarity of a display. Many CRT monitors degauss themselves each time you turn them on, causing a "twang" sound and a shimmery image for a few seconds. Most CRT monitors also offer a way to manually degauss your monitor with a button or control. Older displays required an external magnetic device to degauss them. When you degauss magnetic media, you erase all information on it. |
| Delimited | The separation of data elements in a text file by a character or combination of characters. The character that separates the elements is the delimiter. The most common form of delimited file is tab delimited, as tab characters are not often used within data elements, and are easily understood by most operating systems and character formats. |
| DeMilitarized Zone | A part of a network that is protected by a firewall, but may be accessed by external Internet clients. The DMZ generally contains servers such as SMTP servers, remote access machines. or webservers. Client machines and internal servers that do not need to be accessed by Internet clients are kept in a more protected segment of the network than the DMZ. Alternately, DMZ can be used to refer to the media layer where route peering is done among multiple administrative regions with their own traffic policies. |
| Demon | A term mainly used regarding UNIX processes. A daemon (or demon) is a process that starts and does nothing until it is called by another process or a certain condition is met. This is similar to a TSR program. |
| Demultiplexer | A logic circuit that takes a single input and sends it to one of several outputs. In networking, it is used to describe a device that receives a transmission of several signals over a single line and can properly decode the single line signal into multiple signals. |
| Demux | A logic circuit that takes a single input and sends it to one of several outputs. In networking, it is used to describe a device that receives a transmission of several signals over a single line and can properly decode the single line signal into multiple signals. |
| Denial of Service | A type of network attack that attempts to render a network or Internet resource useless to users, typically by sending large amounts of repeated requests for data. The target may be e-mail services or an IRC server, or it could be access to a particular website. The methods of attack vary, but the end result is that a resource is artificially slowed down or unavailable to legitimate users. |
| DES | An encryption method developed by IBM in 1977. It uses a private 56-bit key that is applied to each 64- bit block of data. The sender and receiver must each know the private key. Anything encrypted by DES encryption has 72,000,000,000,000,000 (or 72 quadrillion) possible keys. DES encryption has been broken, but it took over 14,000 computers operating in succession to crank through codes until the proper key was found. See also Triple DES encryption. |
| Desktop Case | A computer case designed to sit on your desktop. It's wider than it is tall and sturdy enough to put a heavy CRT monitor on top of it. |
| Desktop Management Interface | A system that allows computers to send distress signals to a main system on a network. It is a means to detect problems before they crash the computer irrecoverably. |
| Desktop Management Task Force | This motley crew was assembled to create the DMI standard. |
| Develop | A synonym for programming. It describes the act of creating a computer program. |
| Developer | A person who creates computer programs, and may specialize in one or more methods of creating computer programs, Web pages, or programming languages, such as Java, C++, or Fortran, for example. Microsoft CEO Steve Ballmar is very fond of this term, as noted when he continually stated, "Developers, developers, developers, developers ..." in a now infamous speech to Microsoft personnel. |
| Device Bay Interface Specification | A specification originally designed to provide a simple and generic way of interfacing computers and their components.Device Bay devices are about the size of a VCR tape, and would have interfaced via USB or FireWire, making it easy to plug a new hard drive or other device into the front of your PC. However, Device Bay never took off, as it was expected in 1998 but never arrived. |
| Device Driver | This is basically synonymous with the term "driver." It's a piece of software that tells an operating system specifically how to communicate with a device. For high speed devices such as 3D graphics cards, using an up-to-date device driver is important to guarantee performance and stability. |
| DFS | A Microsoft technology introduced in Windows 2000 that allows multiple servers and shared directories on a network to appear as a single network drive, thus helping to ease the annoying problem of running out of drive letters in complex environments. With DFS, you can have your users' H: drive, for example, be a collection of network resources instead of just a single share. |
| DHCP | A method of automatically assigning a TCP/IP address to a client. A DHCP server is used to dole out a TCP/IP address from a pool of TCP/IP addresses to a client that supports DHCP. When you connect to your ISP over a modem or broadband you are typically assigned a dynamic (non-static) TCP/IP address via DHCP. The big advantage to DHCP is that you don't need to manually assign a TCP/IP address to a client--the DHCP server takes care of that. After an amount of time passes where the client does not contact the server, the server puts the TCP/IP address of the client back into the pool to be assigned to that client or any other client hat requests a TCP/IP address. The disadvantage of DHCP for the DHCP client is that the client is not guaranteed to have a particular TCP/IP address at any given time. For that you want a static IP address. |
| DHTML | This was independently defined by Microsoft and Netscape and implemented in version 4 of their browsers to allow for more dynamic and user-interactive Web pages, and better positioning of Web elements. Both the Netscape and Microsoft versions of dynamic HTML include some support for Cascading Style Sheets, which is a real standard defined by the World Wide Web Consortium. |
| Diagnostics | A procedure or program that is run internally to test a piece of software or hardware and ensure that it is operating properly. For example, if R2-D2 of Star Wars decided to start running into walls, C3PO would probably make him run diagnostics on himself to try to figure out what his problem was. |
| Diamondtron | This is Mitsubishi's answer to Sony's Trinitron. Instead of rectangular pixels, Diamondtron used diamond- shaped ones which supposedly offer crisper text. |
| DIB | The bus architecture between Intel's Pentium II processor, memory, and L2 cache. One bus connects the processor to L2 cache and a second connects the processor to main memory. Having two buses instead of one increases performance over single-bus architectures. In addition, the speed of the external L2 cache can scale up independently from the speed of the system bus.This allows for faster cache access. The final feature of the DIB architecture is a pipeline on the cache to the processor bus that allows multiple simultaneous cache requests. |
| Die size | Simply put, this is the two dimensional (length by width) measurement of a microprocessor. The thickness of the processor is not considered. Typical die sizes range between 20-500 square millimeters with most consumer processors from Intel and AMD around the 80-200 square mm mark. Smaller die size allows more chips to be created with a given amount of raw materials. |
| Differential SCSI | This type of SCSI is used to connect devices that are far apart or that may suffer from interference. Standard SCSI cabling is limited to 6 meters; differential SCSI supports distances of up to 25 meters away from the SCSI host adapter. |
| Digital | This implies a value represented by a group of discrete steps. Some claim that digital representations of images and sound are more accurate; others that the translation of analog sounds and pictures into digital representations causes loss in realism. The bonus to digital reproduction is that if done well enough and designed to correct errors, digital reproduction can sound good over a long period of time. Records and tapes are analog, CDs are digital. Play a CD a million times and it should sound the same. Play a record a million times and it will degrade due to the weight of the stylus changing the physical record over time and the inherent friction involved in analog systems. |
| Digital Audio Tape | This type of magnetic tape, introduced by Sony, at one point threatened to supplant the normal audio cassette with a better quality alternative. Unfortunately, it never really took off due to foolish licensing issues that kept its price very high.However, the small tapes took off big in the computer industry. You can get DAT drives today that hold up to 40 GB of data compressed with DDS-4. Audio DAT tapes are not compatible with data drives. |
| Digital Control | A control that doesn't directly cause a physical change in something, but rather sends a signal that a processor interprets. The processor then makes the change. An example of a digital control would be a television set with buttons instead of knobs. See also Analog Control. |
| Digital Data Storage | A storage standard used with medium cost tape media and tape drives, used mainly for small businesses and departmental backups. DDS tapes are the same size and form factor as DAT tapes used to store music digitally on tape media, but DDS media is more robust and more expensive. There are four different DDS standards: DDS-1 through DDS-4. The four standards allow for backup of 2 GB, 4 GB, 12 GB, and 20 GB worth of uncompressed (native) storage respectively. Storage sizes are typically listed as double for compressed data. DDS media is good for up to 10 years, but should not be used for more than 100 backups or it may become unreliable. DDS tapes are falling to the wayside as DLT, AIT, and other standards offer higher reliability. Sony and HP have both announced that they will not be supporting DDS-5, which pushes DDS data storage up to 40 GB of native storage per tape. |
| Digital Linear Tape | A technology designed by DEC and sold to Quantum used for backing up huge amounts of data (up to 35 GB per tape without compression, 70 GB with compression). The drives are very expensive and so is the media, but they are bulletproof. |
| Digital Millennium Copyright Act | A controversial reform of the U.S. copyright laws that is the first attempt to update those laws for the age of digital technology. It covers circumvention of copyright protections, fair use of copyrighted materials, and protection of ISPs from liability--as long as they follow certain practices. However, DMCA also prohibits circumventing of access controls and copyrights, and bans devices which do such circumvention. The problems with this arise when computer scientists, security analysts, users, etc., are unable to test supposedly secure products for lax security, and if they do find lax security they are unable to tell anyone or they could face prosecution. The first major DMCA case involved a Russian programmer whose company created software that allowed the bypassing of eBook security by Adobe. This allowed legitimate users to back up their eBooks and use them in different formats, which is legal by fair use standards; but it also allowed illegitimate users to potentially make pirated copies of the eBooks, which the DMCA prohibits. |
| Digital Signal level 0 | The signal used to carry a standard analog or digital phone line connection. 24 DS-0 connections can be carried on a T1 line. The speed of the line is either 64Kbps, or 56Kbps if the eighth bit is used for signaling information |
| Digital Signal level 1 | Synonym for T1. |
| Digital Signal level 2 | Synonym for T2 |
| Digital Signal level 3 | Synonym for T3. |
| Digital Signal level 4 | Synonym for T4. |
| Digital Signal level 5 | Synonym for T5 |
| Digital Signal Processor | A DSP is a microprocessor designed to work with analog signals such as video or audio that have been digitally encoded. The DSP then takes these digital representations and performs operations on them. DSPs are used in video, sound, and modem technology. Intel's MMX instruction set was the first attempt to make x86 processors (specifically the Pentium processor line) more capable of DSP operations. This follows Intel's theory of putting all the processor work onto its processors. However, DSP chips are still used in many devices for PCs, as they can keep the CPU from being bogged down. |
| Digital signature | A form of electronic signature that works with a public and private key encryption system and a certificate authority. To sign an electronic document with a digital signature, you use digital signature software to select the document and enter an authorization code that is unique to your digital signature. The signature consists of a string of characters and the signer's name, title, company, certificate serial number, and the name of the certificate authority. |
| Digital Subscriber Line | A form of high-speed Internet access currently competing with cable modems. DSL works over standard copper phone lines. In fact, most DSL service is limited to only copper lines, where fiber optics and Digital Loop Connects will actually cause problems in rolling out DSL to entire areas. DSL is still preferred by many technical users as it is a direct connection that is theoretically not bogged down by other users in the area like cable modems can be. |
| Digital Television | Standard television signals are in analog format. Some HDTV systems (such as Japan's early efforts) use analog signals as well. Digital Television refers to the standard of transmitting and receiving television signals using purely digital transmission. See High Definition Television for more info. |
| Digital to Analog Convertor | An electronic device that converts digital signals into analog signals. You can find DACs in a variety of devices, including sound cards. The DAC would be used to convert digital signals from your computer into analog signals that can be sent to your speakers--assuming you use standard analog speakers. |
| Digital Variable/Versatile/Video Disc | This is much like a CD-ROM except that it stores over 7 times as much data in its simplest form. DVD is the successor to CD-ROM technology. DVD discs are the same size physically as CD-ROM discs, but hold between 4.7-18 GB of data using dual-layer and double-sided discs. The first wave of DVD drives were read-only devices, but newer versions (such as DVD-R/+R/-RW/+RW/-RAM) are beginning to work with write-once and rewriteable media. |
| Digital Video Interface | A connection standard for linking a video card and a display that requires a digital signal, such as an LCD panel. Analog video signals can also be used with the DVI interface. It has 24 pins, 12 for each channel. A single channel can handle 1600x1200 resolution at 60Hz. Dual channels can do 2048x1536 or even higher resolutions. |
| Dill | The abbreviated way to say "DLL," which is a Windows file extension that stands for dynamic link library. |
| DIMM | A circuit board with memory chips on it, very much like a SIMM except that it is larger and contains more pins. DIMMs are 64-bit memory devices, so you just need a single DIMM for a processor with a 64-bit memory path to work properly; or you can potentially double up DIMMs for a 128-bit memory interface if your motherboard supports it. Most memory today is sold on DIMMs. |
| Diode | An electronic device with two electrodes/terminals, one called the cathode and the other the anode, and a single PN junction (which uses part P-type and part N-type semiconductor material). The diode will conduct current in only one direction, and only when the cathode voltage is positive relative to the anode voltage by a specified amount. The specific voltage depends on which semiconductor materials the PN junction is manufactured from. Diodes are often used as a rectifier to convert AC power to DC, but they have many uses. |
| Dip Switch | One or more switches that are housed in a rectangular box on a circuit board. The switches are binary in nature, either on or off for each switch. Dip switches were more common on old ISA cards, and are often used in place of groups of jumpers. Nowadays Plug-and-Play and the abundance of Flash memory for saving settings have all but eliminated these nasty things in consumer PCs. |
| Direct Current | A type of electrical current that moves in one direction at a constant rate, such as a standard 9 volt battery. Batteries provide direct current. See also alternating current. |
| Direct Memory Access | PCs have DMA channels that allow certain devices to directly access memory to speed up the process. In addition to IRQ settings, you used to have to worry a lot about DMA channels, but nowadays those worries are mostly alleviated by smarter component design. |
| Direct Rambus DRAM | One possible future successor to SDRAM, and competitor to DDR SDRAM. DRDRAM (also now simply called RDRAM) was originally developed by Rambus, Inc. This RAM architecture is capable of speeds starting at 266, 356, and 400MHz, and transfers data on the up and down ticks of a clock cycle, where standard SDRAM tops out at about 200MHz. You may see RDRAM referred to at 532, 712, and 800MHz, but that is actually 266*2, 356*2, and 400MHz*2, where the *2 denotes transfer on the up and down tick of the clock. Intel picked RDRAM to be the future of RAM for PCs, but RDRAM ran into many stumbling blocks due to the complexity of manufacturing it. RDRAM was used in the popular Nintendo 64 game machine for its high-speed capabilities and low pin count, necessary for the intense 3D rendering being done on a low complexity system. RDRAM started out using a 16- bit bus, while SDRAM and DDR have 64-bit buses. Thus, 100MHz SDRAM has half the throughput of RDRAM at 400MHz (100*64 = 6,400Mbits/second; 400*2*16 = 12,800Mbits/second). However, newer RDRAM uses a 32-bit bus and is clocked up to 533MHz*2. Still, it never achieved dominance in the PC market. |
| DirectDraw | A set of APIs introduced for Windows 95 and NT that allow programmers to directly access the video controller, allowing for faster graphics response. |
| Directory | The name for a logical container for files. Directories were devised to organize files. Without directories, all the files on your hard drive would be in one big listing. When you request a list of files from a computer, you generally only see the files within one directory. Directories can contain files and/or other directories. Nowadays, most operating systems are calling directories "folders," but we know what they really are. |
| DirectX | A Microsoft technology that first worked under Windows 95 and Windows NT 4.x. Basically, it's a set of APIs that allow programmers to access more directly sound and graphics capabilities of the computer, allowing for, among other things, speedier games. |
| Disc at Once | This is a single-session method of writing data to a CD-R/RW disc that creates a disc in a format suitable for commercial duplication. Basically, the entire disc is written at once in contrast to Track at Once. |
| Disk Drive | Often, this is a synonym for hard drive, but it can also refer to a floppy drive or any type of removable drive that uses magnetic media. |
| Disk Duplexing | There are two forms of RAID 1: disk duplexing and disk mirroring. Disk mirroring involves two hard drives that are on the same drive controller. The same data is written to both drives, so write operations are slower because you must write data to two drives. Read operations are the same speed, as if you only had one drive. Disk duplexing is much like disk mirroring, but each drive is on a separate controller. This speeds up the normally slow write operations and also adds an additional level of redundancy, in case one of your controller cards dies. With RAID 1 you get half the space you paid for because you're writing twice as much data. |
| Disk Mirroring | There are two forms of RAID 1: disk duplexing and disk mirroring. Disk mirroring involves two hard drives that are on the same drive controller. The same data is written to both drives, so write operations are slower because you must write data to two drives. Read operations are the same speed, as if you only had one drive. Disk duplexing is much like disk mirroring, but each drive is on a separate controller. This speeds up the normally slow write operations and also adds an additional level of redundancy, in case one of your controller cards dies. With RAID 1 you get half the space you paid for because you're writing twice as much data. |
| Disk Operating System | This OS is what got it all started for PCs. It was produced by Microsoft and was a 16-bit command line (non-GUI) operating system, designed to run on 16-bit chips. It was still used for years on 32-bit chips. Today you can find a similar command line interface in all Windows products for quick and easy mouse-less file manipulation by running the "cmd" command. |
| Disk Striping | Also known as disk striping, this form of RAID combines two or more hard drives into a single logical drive. Any data is written in blocks first to one drive, then the next, and so on. A RAID 0 configuration sacrifices redundancy for raw speed. The more drives you use the faster your logical drive will be. The space available on the logical drive is the sum of space on all of the drives used, assuming that all drives are the same size. If drives are of disparate sizes, RAID 0 generally only uses a piece of the drive equal to the smallest drive. Of course, if one drive dies, you lose all of the information on the entire RAID. Use RAID 0 with care. |
| Disk Striping with Parity | A RAID 5 configuration utilizes three or more hard drives and stripes the data across them, much like RAID 0. The difference is that parity information is striped across the drives as well, so if you lose any one drive the information can be reconstructed from the parity information. For example, with three drives the first stripe is data (on drive 1), data (on drive 2), parity (on drive 3); then data, parity, data; then parity, data, data. This pattern continues. If one drive fails, you get a mix of parity and data on the remaining two drives, and you can reconstruct all of the data. Of course, before the data is reconstructed the RAID operates in "degraded mode" and is slow. To reconstruct the data you must remove the failed drive and replace it with another, or use a "hot spare." During reconstruction the array continues to be slow. Once the RAID is reconstructed performance returns to normal levels. RAID 5 performance is similar to RAID 0 performance, but a bit slower due to the parity information. Performance increases, like RAID 0, when more drives are added. With RAID 5 you get most of the space that you've paid for, minus one drive's worth. A common option with RAID 5 is the hot spare, where a drive sits idle until needed. If you lose a drive, the hot spare takes over and the RAID is rebuilt automatically. Of course you still get the performance penalty during the rebuilding stage, but it can be set to happen automatically. |
| Diskette | This term is synonymous with floppy disk. You may also hear the long version, floppy diskette. Nowadays most people just say "disk." |
| Distributed Component Object Model | Yet another Microsoft technology. It is a version of the COM that is designed to work across networks and, specifically, the Internet. |
| Distributed File System | A Microsoft technology introduced in Windows 2000 that allows multiple servers and shared directories on a network to appear as a single network drive, thus helping to ease the annoying problem of running out of drive letters in complex environments. With DFS, you can have your users' H: drive, for example, be a collection of network resources instead of just a single share. |
| Divx | This was supposed to be a standard that would offer competition to DVD movies, and allow people to purchase Divx discs that would only be enabled for a couple of days of viewing, eliminating the hassle of returning videotapes or DVD movies after you rent them. Divx ultimately failed due to consumer disinterest. More recently, the Divx name has also served as a slang term for a form of video compression based on MPEG-4. |
| DLL | A library of procedures that programs can call on. The DLL produces output related to the supplied input. DLLs can be somewhat of a black box, as you don't really need to know what's inside them, just what they do. |
| DLP Projector | A display device that can project an image onto a wall or projection screen. This type of projector competes with LCD projectors, and instead of tiny embedded LCD screens it uses microchips covered with microscopic mirrors that are used to reflect light. It's possible to have a DLP projector with three separate DLP chips, similar to an LCD projector with three separate small LCD panels, but some DLP projectors use a color wheel in conjunction with a single DLP chip to produce the red, green, and blue spectrum. |
| DLT | A technology designed by DEC and sold to Quantum used for backing up huge amounts of data (up to 35 GB per tape without compression, 70 GB with compression). The drives are very expensive and so is the media, but they are bulletproof. |
| DMA | PCs have DMA channels that allow certain devices to directly access memory to speed up the process. In addition to IRQ settings, you used to have to worry a lot about DMA channels, but nowadays those worries are mostly alleviated by smarter component design. |
| DMCA | A controversial reform of the U.S. copyright laws that is the first attempt to update those laws for the age of digital technology. It covers circumvention of copyright protections, fair use of copyrighted materials, and protection of ISPs from liability--as long as they follow certain practices. However, DMCA also prohibits circumventing of access controls and copyrights, and bans devices which do such circumvention. The problems with this arise when computer scientists, security analysts, users, etc., are unable to test supposedly secure products for lax security, and if they do find lax security they are unable to tell anyone or they could face prosecution. The first major DMCA case involved a Russian programmer whose company created software that allowed the bypassing of eBook security by Adobe. This allowed legitimate users to back up their eBooks and use them in different formats, which is legal by fair use standards; but it also allowed illegitimate users to potentially make pirated copies of the eBooks, which the DMCA prohibits. |
| DMI | A system that allows computers to send distress signals to a main system on a network. It is a means to detect problems before they crash the computer irrecoverably. |
| DMI Pool | The set of data about a computer and its components, including partition data for your hard drive. When a PC boots it will display the message, "Verifying DMI Pool," and if it will not boot past this it typically means your motherboard is not able to access your hard drive properly. This can be caused by a wrong BIOS setting for your hard drive (try "Auto") or a non-bootable floppy disk if your floppy drive is set to boot first. |
| DMTF | This motley crew was assembled to create the DMI standard. |
| DMZ | A part of a network that is protected by a firewall, but may be accessed by external Internet clients. The DMZ generally contains servers such as SMTP servers, remote access machines. or webservers. Client machines and internal servers that do not need to be accessed by Internet clients are kept in a more protected segment of the network than the DMZ. Alternately, DMZ can be used to refer to the media layer where route peering is done among multiple administrative regions with their own traffic policies. |
| DNS | This service maps TCP/IP numbers, such as 123.12.4.245, to a more easily remembered name, such as www.geek.com. Thus, when you type www.geek.com into your browser, it goes out to the DNS server specified by your ISP and asks for a matching TCP/IP address.If the browser finds a DNS entry for the name you typed in, you see the appropriate website. If not, it lets you know. Every domain name that is actually being used for a website has a corresponding TCP/IP address. When you set up a site you have your ISP add a DNS entry to its DNS servers (or manage it yourself). This entry gets replicated across the Internet in a matter of hours, and, once fully replicated, you can reach your website from any Internet connection. |
| DNS Entry | The DNS routing tables are filled with DNS entries that map TCP/IP addresses to more easily recognized names. If your browser says it can't find a particular DNS entry, here are some possible reasons: you may not be able to communicate with your DNS server, the site may not be responding, or your connection is broken. If a DNS server really doesn't have the entry, there may be nothing mapped to that particular domain name address. If the domain name was just set up, the entry may not have fully replicated to your DNS server. Remember, people can own a domain name (say avgeek.com) and not have an entry for it on any DNS server if they are not paying an ISP to host it. |
| Docking Station | A device into which a laptop connects to gain functionality it has sacrificed for portability. Most laptops have a proprietary connector on the back. Many docking stations have all the ports that you wished your laptop had, but doesn't. Ultra- light laptops don't have many ports because there is no room for them and they add weight. So to compromise, you buy a docking station that has all the ports you need for when you want your tiny laptop to act like a desktop machine. Some companies use docking stations to free users from having to plug and unplug their network and power connections each time they bring the laptop into the office. Just slide the laptop in and go! |
| DOCSIS | This is a standard for cable modems that was ratified by the ITU in March 1998. Before DOCSIS, cable modems made by one brand would not necessarily work on all cable systems. It supports data delivery up to 27Mbps. DOCSIS-compliant cable modems can be upgraded to new DOCSIS versions with a programmable EEPROM. |
| Domain | This term describes the Internet's addressing scheme, and also a security construct in Windows operating systems. For the Internet, domains are represented by domain names such as Geek.com or UGeek.org. These domains are mapped to TCP/IP addresses by DNS servers so that browsers can find websites. Under Windows, domains are groups of server and client machines that exist in the same security structure. You can also define security relationships based on how domains interact with each other. Windows NT 4 domains include a primary domain controller and optionally one or more backup domain controllers to manage security. Windows 2000 domains have domain controllers that share responsibilities more equally, eliminating the primary and backup distinction. |
| Domain Name Service | This service maps TCP/IP numbers, such as 123.12.4.245, to a more easily remembered name, such as www.geek.com. Thus, when you type www.geek.com into your browser, it goes out to the DNS server specified by your ISP and asks for a matching TCP/IP address.If the browser finds a DNS entry for the name you typed in, you see the appropriate website. If not, it lets you know. Every domain name that is actually being used for a website has a corresponding TCP/IP address. When you set up a site you have your ISP add a DNS entry to its DNS servers (or manage it yourself). This entry gets replicated across the Internet in a matter of hours, and, once fully replicated, you can reach your website from any Internet connection. |
| Dongle | The slang term for an external hardware device with some memory inside it that attaches to your computer and dangles off of it (thus the term dongle). Often, companies that sell expensive software packages use dongles as proof that a computer actually has a license to use the software that is being used--the software checks to see if a dongle is installed. If not, it may refuse to run, or run with limited functionality. |
| DOS | see Disk Operating System or Denial of Service |
| Dot Bomb | This is a derogatory slang term for the era of the Dot Com website when many companies were funded with unrealistic expectations and questionable business plans, causing a virtual bomb to go off in the economy as most of the companies eventually collapsed. |
| Dot Com | This literally refers to the suffix of a domain name intended to be used for websites associated with companies. Figuratively, "Dot Com" is used often by investors to describe companies, such as Geek.com, which are mainly Internet-based. This contrasts to brick and mortar. |
| Dot Matrix Printer | This type of printer prints out little dots that can form graphics or characters. It was popular a while back because the only other choice was a daisy- wheel printer that didn't print any graphics. These printers are generally loud, producing a high-pitched buzzing sound, and they don't produce very good graphics. You'll still find them in bank machines, cash registers, and applications that require a physical imprint on paper (to create a carbon copy), but most people don't want anything to do with them. |
| Dot Pitch | The smaller the better, as it relates to CRT monitors. The dot pitch is a measure of distance between phosphor dots of the same color on a CRT monitor. A high dot pitch generally produces a blurred and unclear picture. Smaller dot pitches produce a sharper, crisper image that stands up to close examination. There is contention on how the dot pitch should be measured: horizontally, vertically, or diagonally, resulting in some monitor makers reporting the lowest rating as their official dot pitch. Take the measure of dot pitch with a grain of salt. |
| Dots Per Inch | Most often this term is used to describe printer or scanner resolution. If a printer is said to print at 300 dpi, it will be capable of printing 300 dots horizontally and 300 dots vertically over a square inch. Thus, if you have a printer with a higher dpi value, you should have a crisper image. The same holds true for scanners--a higher dpi theoretically relates to a higher quality scan. Besides scanners and printers, dpi is often discussed when referring to flat panel displays. As flat panel technology increases you get a higher dpi value, and thus can display a larger image in a smaller space without losing any detail. The goal in printers, scanners, and displays is to keep dpi values high enough so that the user is displayed a high-quality image and cannot see the individual dots (or pixels) that make up the image. |
| Double Buffering | A method of smoothing onscreen animation using two buffers to hold images. By rendering both images offscreen, the computer can then display a smoother and less flickery animation by switching from one buffer to the next and back and forth instead of fetching the image and waiting for it to be drawn each time in the same single buffer, which may cause some flickering. |
| Double Data Rate SDRAM | A standard that is used to boost conventional SDRAM memory up to speeds of 200MHz and beyond.Standard SDRAM tops out around 150-166MHz, and DDR SDRAM starts at 200MHz by effectively doubling the speed of 100MHz SDRAM by sending two bits of data per clock cycle. A new standard called DDR II will push DDR SDRAM over 400MHz effective speeds, where standard DDR trails off. |
| Double-layer SuperTwist Nematic | This is a form of passive matrix LCD screen. It is an improved version of the standard supertwist nematic passive matrix LCD screen where the display is divided into two sections and addressed separately to deal with slow switching speeds that result in poor visibility. See also passive matrix. |
| Downstream | The downloading (receiving) of data from the Internet to a client machine. Downstream speeds are typically much greater than upstream speeds in high speed consumer Internet connections such as cable modems and ADSL. |
| DPI | Most often this term is used to describe printer or scanner resolution. If a printer is said to print at 300 dpi, it will be capable of printing 300 dots horizontally and 300 dots vertically over a square inch. Thus, if you have a printer with a higher dpi value, you should have a crisper image. The same holds true for scanners--a higher dpi theoretically relates to a higher quality scan. Besides scanners and printers, dpi is often discussed when referring to flat panel displays. As flat panel technology increases you get a higher dpi value, and thus can display a larger image in a smaller space without losing any detail. The goal in printers, scanners, and displays is to keep dpi values high enough so that the user is displayed a high-quality image and cannot see the individual dots (or pixels) that make up the image. |
| DPMA | This architecture allows computers to have a variety of advanced power management features. |
| Dr. Watson | This is diagnostic software that runs automatically in Windows NT/2000/XP and can be turned on in Windows98/Me. Dr. Watson takes over when a program crashes and writes a snapshot of information about the crash to disk. |
| DRAM | This is the most common form of computer memory. It needs to be continually refreshed in order to properly hold data, thus the term "dynamic." If the power goes off, DRAM loses all of its data, thus making it a bad choice for long-term storage of data. The bonus to DRAM is that it's very fast, much faster than Flash memory or other non-dynamic memory. |
| DRDRAM | One possible future successor to SDRAM, and competitor to DDR SDRAM. DRDRAM (also now simply called RDRAM) was originally developed by Rambus, Inc. This RAM architecture is capable of speeds starting at 266, 356, and 400MHz, and transfers data on the up and down ticks of a clock cycle, where standard SDRAM tops out at about 200MHz. You may see RDRAM referred to at 532, 712, and 800MHz, but that is actually 266*2, 356*2, and 400MHz*2, where the *2 denotes transfer on the up and down tick of the clock. Intel picked RDRAM to be the future of RAM for PCs, but RDRAM ran into many stumbling blocks due to the complexity of manufacturing it. RDRAM was used in the popular Nintendo 64 game machine for its high-speed capabilities and low pin count, necessary for the intense 3D rendering being done on a low complexity system. RDRAM started out using a 16- bit bus, while SDRAM and DDR have 64-bit buses. Thus, 100MHz SDRAM has half the throughput of RDRAM at 400MHz (100*64 = 6,400Mbits/second; 400*2*16 = 12,800Mbits/second). However, newer RDRAM uses a 32-bit bus and is clocked up to 533MHz*2. Still, it never achieved dominance in the PC market. |
| Drive Bay | This is usually a 5.25" wide 1" tall hole in a computer case suitable for the installation of some sort of drive. Some are exposed so that a removable drive (e.g., floppy, CD-ROM) can fit. Some are not exposed and are meant for hard drives that users don't need access to. |
| Driver | A driver is software that works to communicate between an operating system and a peripheral. Think of it as a translator. If you use a crappy driver, your OS won't understand your video card and may become unstable and crash. Hardware manufacturers constantly update drivers to make them faster and more stable. Operating systems typically come with a set of drivers, but peripherals newer than your operating system typically require new drivers which must be installed via CD-ROM, floppy, or downloaded from the Web. |
| Dropdown Menu | A type of menu that appears as a text box with an arrow pointing down in part of the box. It allows a user to click on it, and a list of choices appear below the menu. After the information drops down, one of the items can be selected. It's possible that the information appears above the menu if there is not space below it. |
| Drum | The part of a laser printer onto which the laser produces an electrostatic image. The drum is then rolled in toner and that toner is transferred to paper with pressure and heat. Most drums are coated with selenium for its electrical properties. Selenium is a nonmetallic element in the sulfur family, and it allows the drum to hold a charge and attract toner. |
| DS-0 | The signal used to carry a standard analog or digital phone line connection. 24 DS-0 connections can be carried on a T1 line. The speed of the line is either 64Kbps, or 56Kbps if the eighth bit is used for signaling information |
| DS-1 | Synonym for T1. |
| DS-2 | Synonym for T2. |
| DS-3 | Synonym for T3. |
| DS-4 | Synonym for T4. |
| DS-5 | Synonym for T5. |
| DSP | A DSP is a microprocessor designed to work with analog signals such as video or audio that have been digitally encoded. The DSP then takes these digital representations and performs operations on them. DSPs are used in video, sound, and modem technology. Intel's MMX instruction set was the first attempt to make x86 processors (specifically the Pentium processor line) more capable of DSP operations. This follows Intel's theory of putting all the processor work onto its processors. However, DSP chips are still used in many devices for PCs, as they can keep the CPU from being bogged down. |
| DSTN | This is a form of passive matrix LCD screen. It is an improved version of the standard supertwist nematic passive matrix LCD screen where the display is divided into two sections and addressed separately to deal with slow switching speeds that result in poor visibility. See also passive matrix. |
| DSU/CSU | A piece of hardware that you use to translate the digital data frames of a T1 line into a 10BaseT connection where Internet connectivity is concerned. If the T1 lines are used for voice connections, a CSU/DSU is required to translate the digital frames into signals that your office phone switch can interpret. Basically, the phone network/Internet consists of a bunch of CSU/DSUs talking to one another. When you lease a T1 line, your provider typically supplies you with a CSU/DSU, often with a setup cost. A synonym for CSU/DSU is DSU/CSU. |
| DTS Digital Surround | A form of encoding and decoding surround sound first used in 1993 in the film Jurassic Park. It features 6 discrete channels of audio, with 5 standard speaker channels and one subwoofer channel. DTS can work along with THX speaker certification and placement, or it can work separately. |
| DTV | Standard television signals are in analog format. Some HDTV systems (such as Japan's early efforts) use analog signals as well. Digital Television refers to the standard of transmitting and receiving television signals using purely digital transmission. See High Definition Television for more info. |
| Dual boot | A system that can boot to two different operating systems. Some OSes, such as Windows NT/2000/XP and versions of Linux, allow for dual booting when installed. Of course, you can also use other methods, such as commercial programs that install a special boot partition that is capable of launching operating systems from other partitions. You can also boot to many more than two operating systems on the same machine. |
| Dual Homed | This refers to a computer with two network cards. Such configurations are often used to function as routers in a situation where two networks are connected but dedicated router hardware is not available or is too costly. One common example would be a home computer user who wishes to share Internet access to other computers in a home network. One network card would connect to a cable modem or DSL, and the other would connect to the rest of the home network while some Internet sharing software is used to make the computer function as a router. For corporate use, a dual homed machine can be used for redundancy or increased networking transfer capacity. |
| Dual In-Line Memory Module | A circuit board with memory chips on it, very much like a SIMM except that it is larger and contains more pins. DIMMs are 64-bit memory devices, so you just need a single DIMM for a processor with a 64-bit memory path to work properly; or you can potentially double up DIMMs for a 128-bit memory interface if your motherboard supports it. Most memory today is sold on DIMMs. |
| Dual Independent Bus | The bus architecture between Intel's Pentium II processor, memory, and L2 cache. One bus connects the processor to L2 cache and a second connects the processor to main memory. Having two buses instead of one increases performance over single-bus architectures. In addition, the speed of the external L2 cache can scale up independently from the speed of the system bus.This allows for faster cache access. The final feature of the DIB architecture is a pipeline on the cache to the processor bus that allows multiple simultaneous cache requests. |
| Dualscan | A passive matrix LCD screen that uses a better method of displaying graphics, producing a sharper, more vivid image than standard passive matrix screens. |
| Dumb Terminal | These are hooked up to mainframes, and are little more than a monitor attached to a keyboard. All they are good for is running programs using the mainframe's hard drive and memory, thus the "dumb" in the name. |
| Duplex | A telecommunications term that describes part of the communications between a local modem and a remote computer. In full duplex mode, the remote computer is set up to return the characters that are sent to it so that they can be displayed on your screen. In half duplex mode, the remote computer does not return the characters sent to it. Also see full duplex and half duplex for descriptions of the those terms in other contexts. |
| DVD | This is much like a CD-ROM except that it stores over 7 times as much data in its simplest form. DVD is the successor to CD-ROM technology. DVD discs are the same size physically as CD-ROM discs, but hold between 4.7-18 GB of data using dual-layer and double-sided discs. The first wave of DVD drives were read-only devices, but newer versions (such as DVD-R/+R/-RW/+RW/-RAM) are beginning to work with write-once and rewriteable media. |
| DVD+R | This standard writes to DVD+R media and is write once read many (WORM). It is being pushed by HP, Dell, and others as the next de facto DVD writing standard, along with DVD+RW. |
| DVD+RW | This standard reads standard DVD-ROM discs, and reads and writes to DVD+RW media. |
| DVD-R | This standard is to DVD-ROM like CD-R is to CD-ROM. It uses 4.7 GB disks that can only be written to once, and which then can be read by standard DVD-ROM drives. Apple embraced this standard early, and it is already an entrenched standard that Gateway is also supporting. |
| DVD-RAM | The DVD-RAM standard uses media that can be written and read multiple times, like RAM chips. The first DVD-RAM media held 2.6 GB worth of data per side, and had to be manually flipped over to access the other side. Updates to the standard allowed full 4.7 GB DVD capacity. DVD-RAM drives can read standard DVD disks, but need a special caddy to hold the disks. DVD-RAM media is shaped like the caddy and cannot be inserted into standard DVD drives. DVD-RAM is on the way out. |
| DVD-RW | The rewriteable form of DVD-R. It is being added on to some DVD-R drives to add functionality. DVD-RW disks can write 4.7 GB of data. |
| DVI | A connection standard for linking a video card and a display that requires a digital signal, such as an LCD panel. Analog video signals can also be used with the DVI interface. It has 24 pins, 12 for each channel. A single channel can handle 1600x1200 resolution at 60Hz. Dual channels can do 2048x1536 or even higher resolutions. |
| Dynamic Data Exchange | A method of exchanging data between applications on MacOS, Windows, and OS/2 operating systems. DDE is similar to OLE, but predates it. It enables multiple applications to have access to the same data, such as a word processor having data from a spreadsheet pasted into it. Changes made in either application to the data are reflected in the main document. |
| Dynamic Host Configuration Protocol | A method of automatically assigning a TCP/IP address to a client. A DHCP server is used to dole out a TCP/IP address from a pool of TCP/IP addresses to a client that supports DHCP. When you connect to your ISP over a modem or broadband you are typically assigned a dynamic (non-static) TCP/IP address via DHCP. The big advantage to DHCP is that you don't need to manually assign a TCP/IP address to a client--the DHCP server takes care of that. After an amount of time passes where the client does not contact the server, the server puts the TCP/IP address of the client back into the pool to be assigned to that client or any other client hat requests a TCP/IP address. The disadvantage of DHCP for the DHCP client is that the client is not guaranteed to have a particular TCP/IP address at any given time. For that you want a static IP address. |
| Dynamic HTML | This was independently defined by Microsoft and Netscape and implemented in version 4 of their browsers to allow for more dynamic and user-interactive Web pages, and better positioning of Web elements. Both the Netscape and Microsoft versions of dynamic HTML include some support for Cascading Style Sheets, which is a real standard defined by the World Wide Web Consortium. |
| Dynamic Link Library | A library of procedures that programs can call on. The DLL produces output related to the supplied input. DLLs can be somewhat of a black box, as you don't really need to know what's inside them, just what they do. |
| Dynamic Power Management Architecture | This architecture allows computers to have a variety of advanced power management features. |
| Dynamic Random Access Memory | This is the most common form of computer memory. It needs to be continually refreshed in order to properly hold data, thus the term "dynamic." If the power goes off, DRAM loses all of its data, thus making it a bad choice for long-term storage of data. The bonus to DRAM is that it's very fast, much faster than Flash memory or other non-dynamic memory. |
| EAX | A hardware and software audio standard developed by Creative Labs. It was originally used in SoundBlaster sound boards, and is supported by other companies as well now. EAX offers 3D positional audio and allows the manipulation of sounds so that they can seem to be heard in different listening environments. |
| EBCDIC | A way of encoding 256 characters in binary, much like ASCII, but used mainly on mainframes. Most of the time EBCDIC is only mentioned in translations between EBCDIC and ASCII. |
| EBIOS | This translates between the partition table limitations of a standard computer BIOS and the IDE limitations to provide up to 8 GB of storage space using the IDE interface. Your computer's BIOS has maximums of 1024 cylinders, 256 heads, and 63 sectors (8 GB). The IDE interface has a maximum of 65,536 cylinders, 16 heads, and 256 sectors (128 GB). Put these maximums together (1024 cylinders, 16 heads, and 63 sectors) and you've got a measly 504 MB of data to work with. The EBIOS translates these limitations in such a way that you can actually achieve the BIOS max of 8 GB on one IDE device. Newer IDE standards have since been developed to up the top hard drive size to 128 GB and beyond. |
| ECC | This generally refers to memory chips or motherboards that support the checking for, and possibly correcting of, memory errors in full-parity memory chips. ECC memory uses some extra memory on the memory chips for parity information, and checks to see whether a memory error has occurred. If a minor (one-bit) memory error occurs, the ECC logic will handle it. With full-parity memory (one step below ECC), you will be alerted of a memory error and your system will stop. With non-parity memory you will experience random results, usually crashing, and possible data corruption. If a two-bit or larger error occurs in ECC memory, your system will be halted--similar to what happens with parity memory when any error is encountered. Many caches built into computer microprocessors now have ECC features. |
| Edge Effect | A term used in the semiconductor industry. Square chips are made on silicon wafers that are round. Because of this, there is a certain amount of silicon at the edge of the round wafers on which full chips cannot be constructed. |
| EDO RAM | The successor to standard fast page DRAM. It's a conceptually faster RAM chip that has small bits of SRAM cache built into it. It still runs at slow DRAM speeds (and thus is no longer used. At one time, it was a popular memory format and offered enhanced memory performance. |
| EEPROM | This type of storage is not as fast as DRAM, but maintains data through power loss. It is very similar to Flash memory, except EEPROMs are normally written to one byte at a time, while Flash memory is written to in blocks. See also EPROM. |
| EGA | The standard that came after CGA and before VGA. It allowed resolutions up to 640x350 pixels and 16 colors from a palette of 64. It was soon replaced by VGA. EGA images look squished because the aspect ratio of 640x350 is not flattering compared to the more standard 640x480 resolution of VGA that corresponded exactly to the 4:3 aspect ratio of most computer monitors. |
| EIDE | This standard allowed for two IDE channels that can each support two devices in peaceful coexistence. It also allowed for hard drives up to 8 GB in size and CD-ROM devices. |
| EISA | This is the 32-bit extension of the 16-bit ISA expansion slot. It was generally used only in server machines, and it never caught on for consumers because 32- bit VL-Bus and PCI were more accessible. However, for server machines, EISA beat out VL-Bus and PCI because you could have numerous EISA slots in one machine without any complex wiring. Some server boxes had as many as 14 EISA slots. VL-Bus and PCI initially supported fewer than four slots, and that was a problem if you wanted to install 7 network adapters and 5 RAID cards. EISA made it possible. Nowadays PCI is much more robust, and VL-Bus has long since fallen by the wayside. |
| Electromagnetic Field | A form of radiation given off by all electrical devices. Most notably for computer users, CRT computer monitors used to give off potentially dangerous amounts of EMF radiation, especially from the sides and rear. This radiation was blamed for causing miscarriages and even cancer. Newer monitors are heavily shielded and give off much lower levels of radiation, especially through the front, where users typically sit. |
| Electromigration | This is when metal atoms wander into the dividing layers on a microprocessor. It is caused by the combination of electricity and heat. Processors are designed to run within certain heat and electrical specifications, and if run at higher heat and/or electrical specifications, electromigration may occur. If this occurs to a great degree and enough metal atoms wander off of the lines in a processor, they may permanently ruin the processor by thinning a connection so that it does not work effectively, or even making an electrical connection where one is not intended to be. Overclocking and raising voltage supplied to a processor increases the risk of electromigration. |
| Electronic signature | Any form of electronic identifier, including a digital signature. |
| Electronically Erasable PROM | This type of storage is not as fast as DRAM, but maintains data through power loss. It is very similar to Flash memory, except EEPROMs are normally written to one byte at a time, while Flash memory is written to in blocks. See also EPROM. |
| EMACS | A popular and powerful text editor used primarily on Linux/UNIX systems. It was written around 1975 in the MIT labs by Richard Stallman. EMACS is often compared with VI, another popular Linux/UNIX text editor. |
| Embedded Memory | This is memory that is built directly onto a processor. For example, a graphics chip may have embedded memory instead of using separate memory chips. Use of embedded memory in PCs and PC components nowadays is fairly rare, as attaching a large amount of memory to a chip reduces yields and increases costs. |
| Embedded Processor | A microprocessor used in an embedded system. Typically these processors are smaller, consume less power, and utilize a surface mount form factor, as opposed to more standard consumer processors. Embedded processors are only sold to consumers pre-built into embedded systems, not separately. |
| Embedded System | A system that is located entirely on a processor. All logic is contained in a single chip and has a single purpose. New cars have many embedded systems working to keep emissions low and performance high. |
| EMF | A form of radiation given off by all electrical devices. Most notably for computer users, CRT computer monitors used to give off potentially dangerous amounts of EMF radiation, especially from the sides and rear. This radiation was blamed for causing miscarriages and even cancer. Newer monitors are heavily shielded and give off much lower levels of radiation, especially through the front, where users typically sit. |
| Emoticons | These are groups of text characters that, when viewed sideways, look like facial expressions. For example, the most common one is the happy face :) -- a colon and a close parenthesis. There are many, many more, such as the semicolon wink ;) or the colon-p :P that looks like you are sticking your tongue out. The purpose of emoticons is to convey a feeling in a text-based message that may or may not be obvious to the reader. They are typically used in informal communications, especially when using sarcasm or trying to add extra feeling to the message. |
| Emulate | The act of mimicking the behavior of one computer program, operating system, or piece of hardware with a computer program. Emulation is almost always slower than using hardware designed for a particular purpose. |
| Emulation | The process of using a computer program to mimic the behaviors of another computer program, operating system, or piece of hardware. |
| Emulator | This is usually a program that performs the same operation of another program or a piece of hardware. For example, there are programs that allow a PC to act like a Commodore 64, a Nintendo Entertainment System, or even a Macintosh. These emulators are often developed by talented programmers just to prove that something can be done. |
| Encrypt | The act of making data unreadable in an orderly fashion so that it can be decrypted later. |
| Encryption | The act of altering data to make it unreadable unless you know how to decrypt it. |
| End User License Agreement | The contract found in most software packages that describes the rights to which the user of the software is entitled. Typically, it will explain how many people can use the software, whether it can be used on multiple machines, and whether it is transferable. |
| Enhanced BIOS | This translates between the partition table limitations of a standard computer BIOS and the IDE limitations to provide up to 8 GB of storage space using the IDE interface. Your computer's BIOS has maximums of 1024 cylinders, 256 heads, and 63 sectors (8 GB). The IDE interface has a maximum of 65,536 cylinders, 16 heads, and 256 sectors (128 GB). Put these maximums together (1024 cylinders, 16 heads, and 63 sectors) and you've got a measly 504 MB of data to work with. The EBIOS translates these limitations in such a way that you can actually achieve the BIOS max of 8 GB on one IDE device. Newer IDE standards have since been developed to up the top hard drive size to 128 GB and beyond. |
| Enhanced Graphics Adapter | The standard that came after CGA and before VGA. It allowed resolutions up to 640x350 pixels and 16 colors from a palette of 64. It was soon replaced by VGA. EGA images look squished because the aspect ratio of 640x350 is not flattering compared to the more standard 640x480 resolution of VGA that corresponded exactly to the 4:3 aspect ratio of most computer monitors. |
| Enhanced IDE | This standard allowed for two IDE channels that can each support two devices in peaceful coexistence. It also allowed for hard drives up to 8 GB in size and CD-ROM devices. |
| Enhanced Metafile | A temporary file created by an operating system before data is sent to a printer. The EMFs are created so that control is returned to the program that is printing more quickly. Then the EMF is sent to the print spooler to be converted into language that the printer can understand. Think of the EMF as a quick and dirty scratch file the OS creates so that programs don't have to talk to the (usually slow) printer directly and thus tie up your computer. |
| Enhanced Parallel Port | An enhanced version of the parallel port specification for PCs. Nowadays most parallel ports (and printers) support EPP mode, and EPP mode should be used for maximum performance when frequent bidirectional communications are necessary through the parallel port. However, it is probably better just to go with USB instead. |
| Enhanced SDRAM | A type of SDRAM that includes a small amount of SRAM cache memory for lower latency. It is compatible with SDRAM, but you will not get better performance unless ESDRAM is mated with a memory controller that has ESDRAM support. ESDRAM was never more than a niche product. |
| Enhanced Small Device Interface | This was a popular form of hard drive and controller interface before IDE took over the PC market. |
| Enterprise | The entirety of an organization that uses computers. Typically it refers to very large corporations, or software or hardware solutions designed for large organizations. Enterprise companies usually have numerous locations and hundreds, if not thousands, of users to support--a scenario which requires an entirely different type of IT system and management than a small to mid-sized company. |
| Enterprise Resource Planning | The daunting task of planning and organizing business functions in the enterprise. It also refers to a class of software designed to help organizations do this. Often the installation of this type of software can be a complex task, taking many months and many millions of dollars. ERP software can help companies manage everything from sales and marketing to human resources. |
| Environment | Normally this is your surroundings. Inside your computer, the environment is the settings of a group of variables. Think of it as the surroundings or boundaries set for a process or program running inside your computer. Instead of having a wall and a door, a program in your PC may have x=4 and name="Tara" as its environment. |
| EPIC | This is Intel and Hewlett-Packard's invention, designed to be used on Intel's Itanium processor. It is a method for arranging instructions so that they are ordered to be explicitly parallel. That is, multiple instructions can easily be executed at once, assuming that the hardware supports it. Intel's IA-64 architecture, including Itanium processors, is designed to get the most out of instructions arranged in this manner. |
| EPOC | A 32-bit operating system designed by Symbian and written in C++. It is used in mobile phones and PDAs, including PDAs manufactured by Psion. And yes, that is really what it stands for. |
| EPP | An enhanced version of the parallel port specification for PCs. Nowadays most parallel ports (and printers) support EPP mode, and EPP mode should be used for maximum performance when frequent bidirectional communications are necessary through the parallel port. However, it is probably better just to go with USB instead. |
| EPROM | This is normally read-only memory that retains its information until it is exposed to ultraviolet light. You can often tell a chip is an EPROM by the small window on it that lets ultraviolet light though to program the EPROM. |
| Erasable Programmable Read Only Memory | This is normally read-only memory that retains its information until it is exposed to ultraviolet light. You can often tell a chip is an EPROM by the small window on it that lets ultraviolet light though to program the EPROM. |
| ERP | The daunting task of planning and organizing business functions in the enterprise. It also refers to a class of software designed to help organizations do this. Often the installation of this type of software can be a complex task, taking many months and many millions of dollars. ERP software can help companies manage everything from sales and marketing to human resources. |
| Errata | Minor errors in microprocessor design that are corrected with a new stepping of the processor. The difference between errata and a serious defect is really based on how many people or systems are seriously affected by the issue. It is standard practice for the first volume production of microprocessors to contain errata that is fixed in later generations. Most early errata are worked around by chipsets, BIOS, and drivers. |
| Error | This occurs in a program when it encounters a situation that it was not programmed to deal with. If errors are trapped properly, they can be dealt with by the program itself. If not, they will be dealt with by the operating system on which the program is running. |
| Error Checking and Correcting | This generally refers to memory chips or motherboards that support the checking for, and possibly correcting of, memory errors in full-parity memory chips. ECC memory uses some extra memory on the memory chips for parity information, and checks to see whether a memory error has occurred. If a minor (one-bit) memory error occurs, the ECC logic will handle it. With full-parity memory (one step below ECC), you will be alerted of a memory error and your system will stop. With non-parity memory you will experience random results, usually crashing, and possible data corruption. If a two-bit or larger error occurs in ECC memory, your system will be halted--similar to what happens with parity memory when any error is encountered. Many caches built into computer microprocessors now have ECC features. |
| ESCD | Setup data that is stored in a Plug-and-Play-compatible system BIOS. It consists of the system resource requirements of legacy (non-PNP) devices, and the last working configuration of Plug-and-Play-compliant devices. Plug-and- Play devices that have ESCD entries will use the same resources each time the system boots--as long as no new hardware has been added. This ensures a stable configuration. Plug-and-Play OSes such as Windows 95 and its successors have access to the ESCD, as you would guess if you've ever had to manually change device configurations in Windows (by using the "Device Manager"). |
| ESDI | This was a popular form of hard drive and controller interface before IDE took over the PC market. |
| ESDRAM | A type of SDRAM that includes a small amount of SRAM cache memory for lower latency. It is compatible with SDRAM, but you will not get better performance unless ESDRAM is mated with a memory controller that has ESDRAM support. ESDRAM was never more than a niche product. |
| EULA | The contract found in most software packages that describes the rights to which the user of the software is entitled. Typically, it will explain how many people can use the software, whether it can be used on multiple machines, and whether it is transferable. |
| Exabyte | This is 2^60 bytes or 1024 petabytes. See also petabyte. |
| Execution Unit | The part of a microprocessor pipeline that actually follows and runs the instructions that are sent to the CPU after the instructions are decoded. |
| Expansion Card | This is generally a printed circuit board that can be plugged into a computer, and is designed to increase the functionality of that computer. |
| Expansion Slot | Any type of slot in a computer into which you can plug an expansion card. Examples include ISA, EISA, PCI, and PCMCIA, but there are other types and there will be more in the future. |
| Explicitly Parallel Instruction Computing | This is Intel and Hewlett-Packard's invention, designed to be used on Intel's Itanium processor. It is a method for arranging instructions so that they are ordered to be explicitly parallel. That is, multiple instructions can easily be executed at once, assuming that the hardware supports it. Intel's IA-64 architecture, including Itanium processors, is designed to get the most out of instructions arranged in this manner. |
| Exploit | A means of gaining access to a computer system, typically through a known bug in a program or operating system. Many webservers on the Internet that are not up to date with security patches are vulnerable to exploits, and the effects of these exploits are seen when malicious worms run rampant and spread to unpatched systems. |
| Export | When you export data you are taking that data from a program, database, or file and saving it in another format that is generally easier to manipulate or pull into a different program. An example would be pulling data from a SQL database and saving it as text so that you can use it in a mailmerge. Thus, the exporting frees the mailmerge program from having to understand the complex SQL format--it just needs to understand the exported text file. |
| Extended Binary Coded Decimal Interchange Code | A way of encoding 256 characters in binary, much like ASCII, but used mainly on mainframes. Most of the time EBCDIC is only mentioned in translations between EBCDIC and ASCII. |
| Extended Data Out RAM | The successor to standard fast page DRAM. It's a conceptually faster RAM chip that has small bits of SRAM cache built into it. It still runs at slow DRAM speeds (and thus is no longer used. At one time, it was a popular memory format and offered enhanced memory performance. |
| Extended partition | A type of partition that is an extension of a primary partition. It's possible to have many extended partitions on a hard drive. |
| Extended System Configuration Data | Setup data that is stored in a Plug-and-Play-compatible system BIOS. It consists of the system resource requirements of legacy (non-PNP) devices, and the last working configuration of Plug-and-Play-compliant devices. Plug-and- Play devices that have ESCD entries will use the same resources each time the system boots--as long as no new hardware has been added. This ensures a stable configuration. Plug-and-Play OSes such as Windows 95 and its successors have access to the ESCD, as you would guess if you've ever had to manually change device configurations in Windows (by using the "Device Manager"). |
| Extensible Markup Language | A standard created by the W3C. It is a language with many similarities to HTML. What XML adds is the ability to define custom tags, such as , and define the meaning of those tags within the XML document itself--thus the term "extensible." You can extend the XML language easily. XML is becoming more and more common as more browsers and webservers support it. It is also a very flexible way to exchange data over the Web and interpret and use data from other websites. |
| Extension | DOS, Windows, and, to a lesser extent, UNIX and Linux use the last three characters of a filename, after a period, to signify what type of file a file is, such as text, movie, sound, etc. The MacOS has a file system that contains an identifier for file types that is invisible when looking at the filename, and allows you to call files whatever you want without a messy extension on the end. Some common examples are: .exe (executable file), .bat (batch file), .wav (wave sound file), and .txt (text file). |
| Fab | This is short for fabrication plant. A fab is a factory that takes raw silicon wafers and creates chips with them. Often, fabs are categorized by what process they use. For example, the Intel Pentium chip with MMX was produced in a fab with a 0.35 micron process. Fabrication plants cost billions of dollars to build and are outdated within years. However, they can have a decent life producing volume products after they are no longer considered high-end. |
| Fabless | This term refers to a company that produces chips but doesn't own a fabrication plant, or fab. These companies are starting to become more and more successful at creating chips and renting out other companies' excess fab space to produce their chips. In fact, some fabrication plant owners specifically target such fabless companies to offer their fab space for rent. |
| Fabrication Plant | A fab is a factory that takes raw silicon wafers and creates chips with them. Often, fabs are categorized by what process they use. For example, the Intel Pentium chip with MMX was produced in a fab with a 0.35 micron process. Fabrication plants cost billions of dollars to build and are outdated within years. However, they can have a decent life producing volume products after they are no longer considered high-end. |
| Facsimile | Almost always referred to as fax, this is the term for the electronic transmission of printed documents over a phone line. Usually transmission occurs between fax machines, but you can also use a computer with a fax modem, or a dedicated fax card. |
| Failover | When one device stops working and another device automatically takes its place, typically after a set amount of time has lapsed since the first device stopped responding. Basically, the work done by the device figuratively fails over onto the other device. |
| Fan | A device designed to move air by sucking air into one side and pushing it out the other. Fans are a necessary part of most computing devices because microprocessors heat up when run at high frequencies. Fans move the hot air away and allow the microprocessors to be cooled off. Fans are also used in power supplies to keep them cool. |
| Fast SCSI 2 | This version of SCSI transfers data at 10 megabytes per second. The connections all contain 50 pins. See also Fast-Wide SCSI 2. |
| Fast-SCSI | Plain vanilla fast-SCSI never really existed, but was sometimes used as slang for Fast SCSI 2. This version of SCSI transfers data at 10 megabytes per second. The connections all contain 50 pins. See also Fast-Wide SCSI 2. |
| Fast-Wide SCSI 2 | This version of SCSI upped the pin count to 68, effectively doubling the signal speed of Fast-SCSI 2 to 20 megabytes per second. |
| FAT | This is one way to index the contents of storage media, such as your hard drive. The operating system looks here to know where on the drive files are located. There are different flavors of FAT: the standard DOS flavor is called FAT-16; Windows 95 OSR2 and newer versions additionally supported FAT-32, which allows for larger hard drive partitions. |
| Fat Client | Today's fast PCs are fat clients. They've got lots of memory and big hard drives. They store information and typically run programs locally off of their hard drives. Fat clients usually work in client/server environments, where they can take on some of the processing workload and leave the servers free to serve data. Fat clients are much more customizable and powerful than thin clients, but they are harder to manage and control. For example, users can't install AOL software on a thin client. |
| FAT-16 | The original DOS File Allocation system. It uses a table to tell the OS where on a hard drive or other storage media each file is located. Due to the 16-bit nature of FAT-16, it is limited to hard drive partitions that are 2 GB in size. |
| FAT-32 | An updated FAT standard from Microsoft. It expanded on the aging FAT-16 file system and allowed for much larger partitions. FAT-32 was created as a quick-fix to the problem of computers shipping with hard drives over 2 GB. Prior to FAT-32, computer manufacturers had to messily split hard drives into multiple partitions under 2 GB in size apiece. Imagine the tech support questions: "Why do I have a D: and an E: drive?" |
| Favorite | A method of storing and organizing selected URLs in Internet Explorer. See also Bookmark. |
| Fax | short for facsimile |
| Fax machine | This is generally a single purpose device that can send and receive facsimiles. The machine is normally able to scan in a document and transmit it over a phone line to another fax machine. Also, it can receive faxes from other machines and print them out. |
| FC-AL | A fast, serial-based standard meant to replace the parallel SCSI standard. It is primarily used in high cost server systems, and to connect storage devices to servers. It is software-compatible with SCSI and can handle 126 devices per port. FC-AL connections can run as far as 10 kilometers using optical cabling, or 30 meters with standard copper cabling. |
| FC-PGA | This is Intel's newer packaging of the Socket 370 design. It features a different electrical setup than Socket 370, but is physically compatible. Thus, old Socket 370 motherboards will not be compatible with new FC-PGA chips, but new FC- PGA motherboards may be able to handle Socket 370 processors. It is not clear why Intel made the electrical change. The physical changes put the core closer to the surface, allowing better cooling as the processor core comes in closer contact to the heatsink. |
| FCC | These are the people in the government who decide what's legal and illegal to broadcast, including what frequencies are allowed to be used by whom. |
| FDD | This commonly refers to a 3.5 inch disk drive that uses 1.44 MB 3.5 inch floppy disks. However, the term can be used to apply to any drive that uses floppy disk media. |
| FDDI | This is a fiber optic interface that allows data to travel extreme distances (many miles/kilometers) without signal loss. It is far superior to copper wire for data integrity as well. FDDI is often used to connect Internet, LAN, or WAN backbones together due to these properties. |
| FDisk | The program Microsoft operating systems MS-DOS and non-NT versions of Windows use to create partitions on hard drives. Technically, the program is called fdisk.exe. It uses a text-based interface. Windows 95b first added support for FAT-32 partitions into fdisk. Before that it only supported partitions up to 2 GB using FAT-16. This is also a slang term for wiping a drive out completely, as in "I'm going to F-Disk this drive if Windows crashes one more time!" There are several non-Microsoft equivalents to fdisk, but all serve similar purposes--to allow partitioning of hard disk drives. |
| Federal Communications Commission | These are the people in the government who decide what's legal and illegal to broadcast, including what frequencies are allowed to be used by whom. |
| Femtosecond | One quadrillionth of a second (1/1,000,000,000,000,000 seconds). See also picosecond. |
| Ferroelectric RAM | Initially developed by Ramtron, this is a type of non-volatile RAM that compares favorably to Flash memory in access/read/write speeds, but is harder to produce than Flash or DRAM in high densities. FRAM is used in some portable devices, but hasn't really caught on compared to other memory technologies. |
| Fiber Channel-Arbitrated Loop | A fast, serial-based standard meant to replace the parallel SCSI standard. It is primarily used in high cost server systems, and to connect storage devices to servers. It is software-compatible with SCSI and can handle 126 devices per port. FC-AL connections can run as far as 10 kilometers using optical cabling, or 30 meters with standard copper cabling. |
| Fiber Distributed Data Interface | This is a fiber optic interface that allows data to travel extreme distances (many miles/kilometers) without signal loss. It is far superior to copper wire for data integrity as well. FDDI is often used to connect Internet, LAN, or WAN backbones together due to these properties. |
| Fiber Optic | A method of physical data transmission that is a newer alternative to sending electrical signals over copper wires. The way it works is by pulsing light down a strand of glass. These pulses represent binary code--so far that's no better than copper. The advantage is that a single strand of fiber optic can carry thousands and thousands of different frequencies at once without data loss. |
| Fibre Channel | The British spelling of "fiber", i.e., "fibre" is used to describe this standard. Fibre Channel uses fiber-optic cable to connect computers or peripherals. It is much more expensive than standard copper cabling, and thus has been a niche product with lots of potential. Today it is used sparingly to connect RAID systems to computers, or to connect drives together within high-end RAID systems. |
| Field Programmable Gate Array | A microchip that can be made with thousands of programmable logic gates. Good features of FPGAs include short development times and low production costs. FPGAs are often used for prototype or custom designs, including DSP and logic emulation. |
| FIFO Buffer | An area of memory that holds information in the order in which it was received until the computer has time to use it. |
| File | The base unit data on a hard drive from the perspective of the user viewing the hard drive through an operating system. Computer programs may be one or several files. Additionally, a file may be split (fragmented) into several pieces on a hard drive, but still appear as a single unit to the user. |
| File Allocation Table | This is one way to index the contents of storage media, such as your hard drive. The operating system looks here to know where on the drive files are located. There are different flavors of FAT: the standard DOS flavor is called FAT-16; Windows 95 OSR2 and newer versions additionally supported FAT-32, which allows for larger hard drive partitions. |
| File Extension | DOS, Windows, and, to a lesser extent, UNIX and Linux use the last three characters of a filename, after a period, to signify what type of file a file is, such as text, movie, sound, etc. The MacOS has a file system that contains an identifier for file types that is invisible when looking at the filename, and allows you to call files whatever you want without a messy extension on the end. Some common examples are: .exe (executable file), .bat (batch file), .wav (wave sound file), and .txt (text file). |
| File Format | Applications save files in a certain way. They organize the data in a way that makes sense for the information they are saving and to programs that work with that type of file. There are many standard file formats, such as GIF and JPG. These are graphical formats and are in common use. |
| File Server | Any computer that allows other computers to access files stored on its hard drive or other storage media. The file server also controls who can and cannot access these files. Most other types of servers, including database and webservers, are just glorified file servers. Webservers serve up Web pages, but Web pages are files. Database servers serve up data, but that data is contained in files. However, the distinction is that file servers typically allow access to the files in their raw format, such as through a file management program or command, while webservers and database servers may not allow that form of access. |
| File Transfer Protocol | A common method of moving files from system to system using TCP/IP. To work properly, it requires an FTP client to contact an FTP server in order to transmit data back and forth. |
| Finger | A program that goes to a computer running the finger daemon (service) and returns information about a particular user, if available. Part of the information displayed is the .plan and .project files. Some people update these files often, allowing others to find information about them easily. Originally the finger client was a UNIX program, but now versions are available for other operating systems. So, even though it sounds odd, it's OK to finger complete strangers in cyberspace. |
| FireWire | A serial connection technology that promises to speed data at 200-800Mbps and up. Digital video camera manufacturers and Apple have embraced this connection standard. It is also available on PCs, but adoption is not as widespread. |
| Firmware | The software that is embedded onto a piece of hardware in order to control that hardware. Generally, firmware can be upgraded and is placed on an EEPROM. Sometimes if a new driver for a piece of hardware is released, new firmware will also be released that is required to get the full functionality or performance of the driver. In other cases, firmware will have some bugs or undesirable features, and can be upgraded to work out the problems. Of course, the rest of the hardware cannot be upgraded without replacing pieces of it, so manufacturers try to store as many critical function controls as they can in the firmware in case they need to change them. For them, if a bug is found it is the difference between recalling a product and simply telling their affected customers to upgrade the firmware. |
| First In First Out Buffer | An area of memory that holds information in the order in which it was received until the computer has time to use it. |
| First Person Shooter | This describes a video game that is played from the first person perspective, i.e., looking out of the eyes of the main character. As well, to achieve the "shooter" aspect, the main character usually has some type of weapon, and to achieve your goals you must kill off enemies. The first meaningful game of this genre was Castle Wolfenstein 3D, and other popular examples include the Doom, Quake, and Unreal series. |
| Flash BIOS | This BIOS contains a flash ROM chip that can be updated under certain conditions, but is otherwise static. |
| Flash Memory | A type of non-volatile memory that holds onto its contents even when an electrical charge is not applied. Contrast this to DRAM, which must continually be refreshed even when a charge is applied. Flash memory is used in many applications including PDAs, hardware MP3 players, and some digital cameras. The downsides to Flash memory are that it is slower than DRAM, and much more expensive. |
| Flash ROM | A rewriteable ROM that doesn't lose its info when the power turns off. |
| Flat File | A database that contains a single table and can be easily represented using plain text. This type of database contrasts with a relational database, which can contain any number of tables that are linked together. Often, to keep things simple when transferring data between organizations, people will request a flat file. Common flat file text formats include tab-delimited and CSV. |
| Flat Panel Display | A type of display that has much less depth than a standard CRT-based display. Types of FPDs include gas plasma displays and LCD screens. |
| Flat Screen | This typically refers to a CRT monitor that is made more flat than a standard tube by using more than one electron gun. It is most useful to professionals who rely on the precision of their monitors. It is also better for the standard user because a straight light across the monitor looks straight and not curved. This can also refer to flat panels and projection screens, which are also flat. |
| Flat Shading | The most basic shading technique, in which the entire object is only one color. This causes the image to appear blocky. |
| Flip Chip-Plastic Grid Array | This is Intel's newer packaging of the Socket 370 design. It features a different electrical setup than Socket 370, but is physically compatible. Thus, old Socket 370 motherboards will not be compatible with new FC-PGA chips, but new FC- PGA motherboards may be able to handle Socket 370 processors. It is not clear why Intel made the electrical change. The physical changes put the core closer to the surface, allowing better cooling as the processor core comes in closer contact to the heatsink. |
| Flip-flop | A simple element of memory made up of an assembly of logic gates. Based on inputs, the state of a flip-flop can be changed back and forth, affecting the future output of the flip-flop. |
| Floating Point | A three-part representation of a number that contains a decimal point. The number is represented first by the sign, then the number itself, then decimal position. Some examples of floating point numbers are 4.23423412, 1234.1234234, or 4.00. Floating point numbers offer a specific amount of precision, often 8-bit, 16-bit, 32-bit, or 64-bit. This precision controls how accurately floating point results are represented and calculated during arithmetic operations between floating point numbers. For a simple example, if you have a low level of precision and you divide 1 by 3, you will get 0.33. With a higher level of precision you would see that it is 0.333333333333, and so forth. Thus, your calculation is inaccurate by 0.003333333333 (which is 0.333333333333 - 0.33). A small inaccuracy such as that may not matter if you are pumping out frame rates on a 3D game, but if you are building an airplane's engine you might want to make sure your design program handles a proper amount of precision for the job you are doing. When writing software, larger floating point precision takes more space to store, and may be slower depending on the hardware you are running on. |
| Floating Point Operation | This describes a single manipulation of a floating point number in a microprocessor. One measure of the speed of a microprocessor is how many FLOPs can be accomplished in a second. |
| Floating Point Unit | The part of a microprocessor that is designed to handle floating point calculations. Often the efficiency of this part of the processor will decide whether a processor is successful or not. Cyrix M-II chips and AMD K6-2 chips had weak floating point units when compared to Intel Pentium III processors, thus limiting their success. AMD's Athlon chip had a strong floating point unit, and it was very successful against the Pentium III. Floating point performance matters a lot in games and complex data manipulations, thus the "pro" or "Geek" segment of the market that drives system buys and recommends components. |
| FLOP | This describes a single manipulation of a floating point number in a microprocessor. One measure of the speed of a microprocessor is how many FLOPs can be accomplished in a second. |
| Floppy disk | Any type of disk media which is not rigid. Often it's contained in hard cases, which can lead to confusion in identification. Commonly, the term is used to describe 1.44 MB 3.5 inch diskettes, but it applies to any media. Zip disks, for example, are floppy in nature if removed from their casing. |
| Floppy disk drive | This commonly refers to a 3.5 inch disk drive that uses 1.44 MB 3.5 inch floppy disks. However, the term can be used to apply to any drive that uses floppy disk media. |
| FM synthesis | A method of creating music using frequencies to represent instruments. As you can imagine, this does not create beautiful and complex music, but flat, lifeless electronic sounds. It was useful--and often used--in early video games before wavetable synthesis became widespread. |
| Folder | A term coined to be synonymous and more accessible than "directory." Now the terms are basically synonymous, but folder tends to imply a more graphical interface for managing files. |
| Font | As it relates to computers today, a font is a specific style of displaying characters (a typeface), often scalable to a variety of sizes. "Arial" is a font, for example. This differs from the traditional definition of font, where each style and size was its own font (i.e., "9 point Arial" as opposed to simply "Arial"). |
| Foo | FooBar is a derivative of the acronym FUBAR, changed for symmetry. FUBAR stands for Fucked Up Beyond All Recognition. Sometimes used as a whole by programmers to describe data loss, foo and bar are also often used separately when a quick and random name is needed. Programmers (mostly those dirty UNIX guys) got tired of trying to think of random words, so they use foo and bar. |
| FooBar | FooBar is a derivative of the acronym FUBAR, changed for symmetry. FUBAR stands for Fucked Up Beyond All Recognition. Sometimes used as a whole by programmers to describe data loss, foo and bar are also often used separately when a quick and random name is needed. Programmers (mostly those dirty UNIX guys) got tired of trying to think of random words, so they use foo and bar. |
| Footprint | This refers to the general size of something, whether physical or virtual. The footprints of small Internet appliances are compared against those of larger PCs, as are smaller LCD screens vs. CRT screens. Different operating systems and programs have their own footprints in the amount of bytes they typically take up on a hard drive, or the amount of physical memory they consume while running. |
| Form Factor | Typically this refers to the compatibility among PC motherboards, cases, and power supplies. A motherboard, case, and power supply with the same form factor can be used together. Some examples of form factors are AT, ATX, Baby AT, or NLX. Some cases, power supplies, and even motherboards will work in multiple form factors. This is commonly seen in older computer cases that will work with AT or ATX motherboards. |
| Format | After partitioning your hard drive, it must be formatted so that it can be used by the operating system. Formatting basically makes your hard disk ready for initial use. The same procedure must be done to removable media such as floppy disks. Some types of formatting wipe out the whole disk, while others just set up the framework for data to be written using a type of quick format. Another type of formatting is a SCSI low-level format. This type of format makes a drive ready to be used by a SCSI controller. When you format a drive you typically lose all information on that drive. |
| Fortran | A high-level programming language, a bit more advanced than BASIC but not quite as complex as C. This language refuses to die because it is so huge in the scientific research community. It's not a tough language to learn, and it's fairly powerful. About 60% of scientific programming is still done in Fortran. |
| Foundry | A synonym for semiconductor fabrication plant. A foundry is the actual location that produces microprocessors. The term foundry initially referred to a location where metal was poured into molds, but in technology speak it refers to the place where microprocessors are molded. |
| FPD | A type of display that has much less depth than a standard CRT-based display. Types of FPDs include gas plasma displays and LCD screens. |
| FPGA | A microchip that can be made with thousands of programmable logic gates. Good features of FPGAs include short development times and low production costs. FPGAs are often used for prototype or custom designs, including DSP and logic emulation. |
| FPS | see First Person Shooter or Frames Per Second |
| FPU | The part of a microprocessor that is designed to handle floating point calculations. Often the efficiency of this part of the processor will decide whether a processor is successful or not. Cyrix M-II chips and AMD K6-2 chips had weak floating point units when compared to Intel Pentium III processors, thus limiting their success. AMD's Athlon chip had a strong floating point unit, and it was very successful against the Pentium III. Floating point performance matters a lot in games and complex data manipulations, thus the "pro" or "Geek" segment of the market that drives system buys and recommends components. |
| Fractional T1 | This term refers to using a theoretical "piece" of a T1 line, such as 128Kbps', 256Kbps', or 512Kbps' worth of the 1.5Mbps T1 line. Many ISPs offer fractional T1 as a lower-cost alternative to a full T1 and a higher-cost alternative to ISDN. However, if you check the prices it's almost always worth it to go for full T1. The phone company has to install a full T1 connection anyway, and you'll just be paying a bit more a month. Basically, since a T1 is only four wires the full line is installed and the ISP will only allow traffic up to the limit for which you are paying. |
| Fragment | A piece of a file. When a file is written to a hard drive it is sometimes written in multiple fragments because there is no contiguous space available that is large enough to store the file. See fragmentation. |
| Fragmentation | This occurs when a hard drive writes a file in multiple segments instead of in a physically contiguous area. A higher level of fragmentation means that most files are fragmented, and many files contain lots of fragments. A low level of fragmentation implies that more files are in one piece, and that if files are fragmented they are only in a few fragments. For example, say you have two files, file A and file B and you write them both to a hard drive. A low level of fragmentation may be represented by: AAAABBBB. A high level of fragmentation may be represented by: AABBABABA. Fragmentation is caused by deletion of small files, and then trying to fit larger files into the leftover spaces. Over time it is a common occurrence that is unavoidable in most file systems. |
| FRAM | Initially developed by Ramtron, this is a type of non-volatile RAM that compares favorably to Flash memory in access/read/write speeds, but is harder to produce than Flash or DRAM in high densities. FRAM is used in some portable devices, but hasn't really caught on compared to other memory technologies. |
| Frames Per Second | This term relates to video or 3D games, and is the amount of single full screen (or full window) pictures (or frames) that are displayed each second to generate what appears to be a moving image. Typical digital video displays at around 30 FPS. Higher frame rates are not really necessary, as the human eye cannot typically handle more than about 30 FPS. Some games will average 30 FPS or higher and look choppy. Usually this is due to intense scenes that cause the action to dip below 30 FPS for short periods of time. Rates of over 100 FPS in games are common nowadays with less complex 3D action games, but do not necessarily add to the experience of playing a game. |
| Free text search | This type of search allows you to give a fragment of a word and have it found in any part of that word. For example, doing a free text search for "the" could return "Thesis," "Blithe," and "Diphtheria." |
| FreeBSD | A UNIX-like operating system that runs on the Intel x86 platform and is based on an OS developed at University of California at Berkeley. It is now a no-cost operating system, and the source can be downloaded and modified. |
| FreeBSD license | An Open Source license that allows programmers to decide whether or not to provide the source code of their programs with the software. Contrast that to the GPL license, which requires developers to provide source code on demand. The FreeBSD license is more flexible for programmers, especially those who spent a lot of time working on their software and want to profit from it. |
| Frequency Modulation | A method of sending and distinguishing radio signals by modifying the frequency of the radio wave. See also AM. |
| Frequently Asked Questions | A document that lists the most common questions about something (with the answers, of course). A simple way to find information on a complex topic is to do an Internet search for _topic_ FAQ, where _topic_ represents the topic for which you are looking. |
| Front Side Bus | The speed of the bus connecting the microprocessor, its chipset, and connected main memory. In architectures where the processor interacts directly with main memory, the definition of a singular front side bus is less clear. In such a case you would have to specify two FSB speeds, one for the connection to main memory and one for the connection to the processor chipset. |
| Front-end | The part of a program or process that the user interfaces with and controls. See also back-end. |
| FSAA | A method used by 3D graphics cards to provide anti-aliasing to all objects in a 3D environment. This acts to smooth out the jagged appearance of edges on some 3Dobjects. Different graphics cards have different implementations of FSAA, and image quality varies greatly. |
| FSB | The speed of the bus connecting the microprocessor, its chipset, and connected main memory. In architectures where the processor interacts directly with main memory, the definition of a singular front side bus is less clear. In such a case you would have to specify two FSB speeds, one for the connection to main memory and one for the connection to the processor chipset. |
| Full Duplex | Originally this referred to a communication between a modem and a remote system, where characters were sent both ways over the phone line so that they could be accurately displayed on a terminal. Now full duplex has taken on the meaning that signals can be sent in both directions at the same time, such as in network communications. This either requires twice the amount of wires or differing frequencies for each type of signal so they do not interfere when on the same wire. Full duplex network connections are preferred, especially for servers, which must send and receive a lot of data. |
| Full parity | This is synonymous with full duplex, but most often used when describing dial-up modem communications standards. |
| Full Screen Anti-Aliasing | A method used by 3D graphics cards to provide anti-aliasing to all objects in a 3D environment. This acts to smooth out the jagged appearance of edges on some 3Dobjects. Different graphics cards have different implementations of FSAA, and image quality varies greatly. |
| Function key | One of the set of 12 keys at the top of a standard computer keyboard. These keys are labelled F1 through F12. The keys are basically general purpose extra keys so that programmers can assign the keys to special functions in their programs. One handy and common use of F3 in applications is to "Find again," or find the value again for which you most recently searched. |
| Fuse | A device used to protect devices from excessive electrical current. It contains a conductor that melts and breaks the current flow when too much electricity flows through it. Once a fuse is blown it must be replaced with another one to close the circuit and allow electricity to flow again. |
| Fuzzy Logic | Logic without an absolute true or false. Instead, you have gradients of true and false. This is necessary for solving some problems, especially those involving artificial intelligence. For example, the question, "Do I get some food now?" isn't always yes or no, and varies due to environmental factors and degrees of hunger. |
| G.Lite | G.Lite is a form of ADSL that does not require a splitter to separate voice and Internet traffic. It can operate at speeds of up to 1.5Mbps (like a T1) downstream, with upstream rates of 128Mbps. G.Lite was designed to be a more easily implementable form of ADSL so that the install is minimal for consumers. |
| Game Console | A consumer gaming system that is usually sold in retail stores and toy stores. It differs from a standard computer in that it is designed from the ground up to provide a certain amount of game playing power at a specific price point, and typically is very limited in upgradeability and expansion. |
| Game Port | A 15-pin analog port on a PC used specifically for game controllers like a joystick. It also doubles as a MIDI connector. Usually you find one on the back of your sound card. |
| Gamma | In computer graphics and digital video, this refers to a numerical parameter that describes the nonlinearity of intensity reproduction. Basically, as colors get lighter the human eye has more trouble discerning them, and a gamma setting is used to compensate for this so that shades of color on an object, such as those caused by shadows, can be discerned properly. Incorrect gamma settings can cause colors to look too dark or too light, losing detail to the viewer. |
| Gamma Correction | The process of altering the gamma of computer graphics, pictures, or video in order to make the picture show up properly and enable the proper recognition of shades of color. Some graphics accelerators have gamma correction features, as early 3D games often had issues with colors appearing too dark. |
| Garbage Collection | A process where dynamically allocated blocks of memory are reclaimed while a program executes. Garbage collection is normally performed by the garbage collector, which is part of the runtime system. However, it is possible to explicitly write code to do garbage collection as well. Automatic garbage collection is triggered when the amount of free memory blocks falls below a certain threshold. |
| Gas Plasma Display | A type of monitor technology that was initially used to create small monochrome displays for early portable computers. Now it is typically used to create large monitors that are a only a few inches thick. Older models produced only orange images, but now gas plasma technology can be used to create full color displays. The technology works by creating a matrix of red, green, and blue pixels from plasma bubbles that are turned on or off by selectively powering them. |
| Gate | A gate is a tiny electronic switch. These switches, when linked together, can perform logical functions. Basically, gate is the logical term for transistor. |
| Gateway | The computer or device onto which the first hop needs to go to get out of your network and onto another network or the Internet. The gateway, as it relates to TCP/IP, is tried when a resource is not found on the local network. |
| Gbit | This refers to approximately one billion bits. More exactly, it is 2^30, or 1,073,741,824 bits. |
| Gbps | A rate of data transfer of one gigabit of data per second. |
| GDI | A standard set of programming functions provided by Microsoft for the production of graphic output in Windows. Microsoft provides these functions in its Software Development Kits. The functions are device-independent, so you can use them on any graphics card as long as Windows is installed. |
| Geek | (1) A formerly derogatory term given to the outcast elite, usually lacking in social graces. The term has been used so liberally by the masses of people that computer gurus have taken it to heart as not being derogatory, but rather the name given to scientifically savvy folk. (2) A carnival performer who performs grotesque acts, such as biting the heads off of live chickens. |
| General Packet Radio Service | A mobile phone 2.5G technology that allows short bursts of data between a phone and a network such as the Internet. The short transmissions allow for less costly connectivity than a constant connection, but work best with specialized services designed for such types of communication. |
| General Protection Fault | An error that is caused in a Microsoft Windows operating system when a program tries to access a protected section of memory that it should not be accessing. These errors are typically caused by lack of hard drive space for virtual memory, poorly written software or drivers, or hardware conflicts. |
| Genetic Algorithm | An algorithm that uses fuzzy logic and can refine itself based on its ability to select proper answers. Often, a human must tell the algorithm what it did right and what it did wrong so that it can select better results the next time it is run. |
| Geographic Information System | A system for capturing and manipulating data relating to the Earth. A common use of GIS is to overlay several types of maps (for example, train routes, elevation data, street maps) to determine useful data about a given geographic area. |
| Gflop | The ability of a system to compute one billion floating point operations in one second. AMD's K6-2 processor and Motorola's G4 processor can achieve speeds of over 1 Gflop, for example, and newer chips can do multiple Gflops. The problem with trying to measure Gflops is determining a standard method of measuring floating point operation or instructions. Even if you do this, it's not clear that the measurement would reflect on real world usage. |
| GIF | Invented by CompuServe for efficient transmission of graphics, this format can only support 256 colors, or 8 bits. The newer revision, 89a, allows for multiple images in one file to simulate animation. Unisys owns the patent to a form of compression used in GIF files and occasionally decides to demand licensing fees. Thus, you may want to use the newer and completely free PNG format instead of using GIF files. |
| Gig | This refers to approximately one billion bytes. To be specific, it is 2^30, or 1,073,741,824 bytes. |
| Gigabit | This refers to approximately one billion bits. More exactly, it is 2^30, or 1,073,741,824 bits. |
| Gigabyte | This refers to approximately one billion bytes. To be specific, it is 2^30, or 1,073,741,824 bytes. |
| GigaFlop | The ability of a system to compute one billion floating point operations in one second. AMD's K6-2 processor and Motorola's G4 processor can achieve speeds of over 1 Gflop, for example, and newer chips can do multiple Gflops. The problem with trying to measure Gflops is determining a standard method of measuring floating point operation or instructions. Even if you do this, it's not clear that the measurement would reflect on real world usage. |
| Gigapixel | 1,073,741,824 pixels. This is a measure of how fast data can be moved through a graphics accelerator, as in gigapixels/second. See also megapixel. |
| GIMP | A free, Open Source program designed for creation or manipulation of images, much like Photoshop or Paint Shop Pro, but for use on Linux/UNIX platforms. |
| GIS | A system for capturing and manipulating data relating to the Earth. A common use of GIS is to overlay several types of maps (for example, train routes, elevation data, street maps) to determine useful data about a given geographic area. |
| GlidePad | A touch-sensitive pad about 2" x 2" that will track the touch of a finger. It is not a pressure sensor, so there is no need to press down, only to touch. This device acts like a mouse for pointing, and you can tap quickly on the pad to mimic a click. |
| Glitch | This often refers to a bug in a program that is somewhat different than a freeze or a crash, usually causing erroneous or garbage results to be displayed. The term glitch sounds like a mess, and that's what programs with glitches create. |
| Global Positioning System | A system of satellites around the Earth that broadcast the time via radio signals based on an internal atomic clock. GPS devices can receive the signals from multiple satellites, and by measuring the time it took the signal to arrive they can determine your current position on the Earth. |
| Global System for Mobile Communications | A 2G digital standard for cellular phone communications that is used in many countries. GSM communications bands range from 900-1800MHz. The GSM initials were initially derived from the French "Groupe de travail Spciale pour les services Mobiles." Globally Unique Identifier (GUID) - A unique 128-bit value generated by some Microsoft applications. An example of the GUID format is: 12345678-1234-1234-1234-123456789ABC. The GUID will use the MAC address of your network card as part of itself if you do have a network card installed, potentially marking documents created by Microsoft applications with a number that could be traced back to your PC. |
| GNU | A free software movement whose acronym stands recursively for "GNU's Not Unix." GNU was started in 1984 as a means to create an entire system of software, including operating systems, programming languages, and applications that are all free. In this context free means free of cost, free to distribute, free to modify, and free to distribute modified versions. The main thing you are not free to do is claim ownership of GNU software. |
| GNU Public License | The short of it is quite simple: if you based anything on GPLed software, you MUST provide the source code to your software upon request. The legalities of this simple concept go on at great length, and periodically new revisions of the GPL appear as holes are found and fixed. The primary rival to this is the BSD license, which is "free beer" for the community, but developers of FreeBSD license software can choose to keep their source hidden. |
| Gnutella | This is a distributed file swapping program developed by Nullsoft, which is owned by AOL. AOL attempted to shut down Gnutella, but once it was released onto the Web AOL could no longer control it. Gnutella connects you to a large network of users who make files available on their computers, allowing you to download those files and share your own files if you like. Unlike other file swapping mechanisms, Gnutella is fully distributed and does not depend on any one corporation or entity to keep it running. Gnutella clients function as clients and servers. |
| Gold Master | The final beta version of a program that is ready to be released to the public. The entire goal of the beta process is to arrive at the gold master candidate. Once it is tested successfully, it becomes the gold master and is shipped out to be duplicated (if it's a CD or floppy) and/or uploaded to the Web. The process of creating the gold master is often referred to as "going gold," or you could say that certain software "went gold" when the golden master was released. |
| Goldfinger | One of the generic terms used to describe the group of gold connectors inside the AMD Athlon Slot A cartridge. The connector allows you to plug devices into it that can change the clock multiplier and voltage of the Athlon cartridge. However, you must break open the plastic cartridge to get to the connectors. There are many devices available that can be used to connect to the Goldfingers; these are also referred to as Golden Fingers or Goldfingers. Nowadays Slot A Athlons are outdated. |
| Googol | This stands for the number 10 raised to the power of 100 (10^100), or a one followed by 100 zeros. |
| Googolplex | The number 10 raised to the power of 1 google, or (10^(10^100)), which is the number 1 followed by 10^100 zeros. |
| Gouraud Shading | This method analyzes the color at each corner of the triangle and takes an average of the colors where the corners meet. This causes the triangles to "bleed" together, making for a smoother, clearer, more colorful image. |
| GPL | The short of it is quite simple: if you based anything on GPLed software, you MUST provide the source code to your software upon request. The legalities of this simple concept go on at great length, and periodically new revisions of the GPL appear as holes are found and fixed. The primary rival to this is the BSD license, which is "free beer" for the community, but developers of FreeBSD license software can choose to keep their source hidden. |
| GPRS | A mobile phone 2.5G technology that allows short bursts of data between a phone and a network such as the Internet. The short transmissions allow for less costly connectivity than a constant connection, but work best with specialized services designed for such types of communication. |
| GPS | A system of satellites around the Earth that broadcast the time via radio signals based on an internal atomic clock. GPS devices can receive the signals from multiple satellites, and by measuring the time it took the signal to arrive they can determine your current position on the Earth. |
| GPU | A microprocessor specifically designed for processing 3D graphics data. This term was first coined by NVIDIA to describe its GeForce 256 chip. NVIDIA justified the name by stating that its graphics chip had a similar amount of transistors as then-current CPU chips. Now GPU has become a more widely used term to describe the complex chips that power 3D graphics cards. |
| Graphical Interchange Format | Invented by CompuServe for efficient transmission of graphics, this format can only support 256 colors, or 8 bits. The newer revision, 89a, allows for multiple images in one file to simulate animation. Unisys owns the patent to a form of compression used in GIF files and occasionally decides to demand licensing fees. Thus, you may want to use the newer and completely free PNG format instead of using GIF files. |
| Graphical User Interface | Any system that uses graphics to represent the functions of a program. All Windows operating systems are GUIs. |
| Graphics | The pictures that computers display. Not text, but just about everything else. |
| Graphics card | The graphics card is an add-in board that plugs into the motherboard and sends signals out to the monitor to represent what should be shown on the screen. A graphics card can send simple text, or it can be designed to represent intense 3D graphics, as most cards do today. |
| Graphics Device Interface | A standard set of programming functions provided by Microsoft for the production of graphic output in Windows. Microsoft provides these functions in its Software Development Kits. The functions are device-independent, so you can use them on any graphics card as long as Windows is installed. |
| Graphics Processing Unit | A microprocessor specifically designed for processing 3D graphics data. This term was first coined by NVIDIA to describe its GeForce 256 chip. NVIDIA justified the name by stating that its graphics chip had a similar amount of transistors as then-current CPU chips. Now GPU has become a more widely used term to describe the complex chips that power 3D graphics cards. |
| Gray Market | The market where goods are sold in an unauthorized manner, or before their expected release date. Sometimes gray market goods have been stolen from the manufacturer, or have been dumped by the manufacturer to create a result such as flooding the market. Gray market products are more likely to be remarked as different products or unsupported by their manufacturers than products purchased through proper channels. However, gray market goods are sometimes cheaper or available before their time, making them attractive to potential purchasers. One of the largest sources of gray market products are computer shows, where many gray market goods are sold "as is." |
| Greenie | A slang term for a CD-Recordable disk. The media was originally green on the recording side, thus the term. Nowadays CD-R media may be green, blue, or gold on the recording side. |
| Ground | Electrically speaking, this is a neutral point that can absorb excess electricity. Often it is the ground itself (as in the ground you stand on), but it is also commonly a large piece of metal, such as the chassis on a car. Electrical devices have to be connected to a ground so that the ground can disperse any excess electrical charges. |
| GroupWare | This term is used to describe any form of software designed to allow a group of people to easily share ideas and data. Examples include Lotus Notes, Novell GroupWise, and Microsoft Exchange. |
| GSM | A 2G digital standard for cellular phone communications that is used in many countries. GSM communications bands range from 900-1800MHz. The GSM initials were initially derived from the French "Groupe de travail Spciale pour les services Mobiles." GTL (Gunning Transceiver Logic) - A low-power standard for electrical signals used in CMOS circuits which allows for low electromagnetic interference at high speeds of transfer. GTL requires only 50% voltage swings to switch between on and off states, which is a small deviation compared to previous technologies. GTL is a parallel bus standard that typically operates at speeds of between 20 and 40MHz. |
| GTL+ | This is an improvement to the GTL standard that allows for bus operation at speeds of between 60 and 125MHz typically. It remains a parallel signaling standard. |
| GTLP | This is an improvement to the GTL standard that allows for bus operation at speeds of between 60 and 125MHz typically. It remains a parallel signaling standard. |
| Gunning Transceiver Logic | A low-power standard for electrical signals used in CMOS circuits which allows for low electromagnetic interference at high speeds of transfer. GTL requires only 50% voltage swings to switch between on and off states, which is a small deviation compared to previous technologies. GTL is a parallel bus standard that typically operates at speeds of between 20 and 40MHz. |
| Gunning Transceiver Logic Plus | This is an improvement to the GTL standard that allows for bus operation at speeds of between 60 and 125MHz typically. It remains a parallel signaling standard. |
| Gustafson's Law | In response to Amdahl's Law on limitation of effectiveness of parallel computing due to a serial (non-parallelizable) component of code, Gustafson's Law was developed to show that you can achieve over a 1000-fold speed-up using 1024 processors. It states that if the size of most problems is increased sufficiently, you can achieve any given efficiency by increasing the amount of processors. |
| H.323 | An ITU-T standard for transferring multimedia videoconferencing data over packet-switched networks, such as TCP/IP. There is a LAN standard for high-quality video, and an Internet standard for lower-bandwidth video over lines as slow as 28.8Kbits. |
| H_Key | A part of the Windows registry hive. The hive contains several different pieces, or keys. |
| Hacker | Someone who seeks to understand computer, phone, or other systems strictly for the satisfaction of having that knowledge. Hackers wonder how things work, and have an incredible curiosity. Hackers will sometimes do questionable legal things, such as breaking into systems, but they generally will not cause harm once they break in. Contrast a hacker to the term cracker or malicious hacker. |
| HAL | The portion of the operating system that lets programs deal with hardware directly. This allows programs needing more speed from the computer to bypass the standard OS calls to hardware. So, instead of calling the Windows' API to draw a dialog box, you would go through the pain of actually drawing it out line by line--that's much faster, but much harder to write. This is of particular importance when coding games. |
| Half Duplex | Originally a modem communications term, half duplex now mainly refers to network communications that transmit in one direction at a time. Also see duplex and full duplex. |
| Handheld Devices Markup Language | Part of the Wireless Application Protocol (WAP) , allowing text portions of Web content to be separated from graphical content for display on wireless devices. |
| Hard Copy | This refers to information printed out on paper, as contrasted to information stored in electronic formats. |
| Hard Disk | This is commonly the slang term for a hard drive. It refers to the type of re-writeable media that is inflexible, as opposed to a floppy disk. A hard drive typically contains multiple hard disk platters. |
| Hard Drive | A device that physically stores data in your computer. It's much like a floppy disk, but the system is closed and the disks are hard (usually metal, although some glass versions have been developed). The closed system gives the possibility of more precision, so the drive is much faster and can hold much more data. |
| Hard Reset | This refers to the forced, immediate shutdown and restart of a PDA or other device by means of hardware. This is typically done by pushing a sequence of buttons or a reset button, and usually only after it has become impossible to do a soft reset. |
| Hardware | Any physical pieces of a computer. For example, the computer chassis itself, a monitor, a printer, DRAM, and video cards are all hardware. See also software. |
| Hardware Abstraction Layer | The portion of the operating system that lets programs deal with hardware directly. This allows programs needing more speed from the computer to bypass the standard OS calls to hardware. So, instead of calling the Windows' API to draw a dialog box, you would go through the pain of actually drawing it out line by line--that's much faster, but much harder to write. This is of particular importance when coding games. |
| Hardware Compatibility List | A list of computers and peripherals that have been tested by Microsoft to work with Windows NT or Windows 2000. If you run those operating systems on equipment that is not listed on the HCL, it is not guaranteed to work, but it might. Basically, if you install NT/2000 on hardware that's not on the HCL, you are on your own. However, it is done frequently with decent success. |
| Hardware Emulation Layer | This provides software-based emulation of features that are not directly available in hardware. |
| Hash table | A table that contains "hash values," generally used for speeding up searching algorithms on sorted data. For example, a hash table for a dictionary might contain all the letters of the alphabet and the page numbers where each letter starts. That way, instead of searching through from start to finish for each word, you just use the hash table and get a big head start. |
| HCL | A list of computers and peripherals that have been tested by Microsoft to work with Windows NT or Windows 2000. If you run those operating systems on equipment that is not listed on the HCL, it is not guaranteed to work, but it might. Basically, if you install NT/2000 on hardware that's not on the HCL, you are on your own. However, it is done frequently with decent success. |
| HDML | This stands for Handheld Devices Markup Language, now called Wireless Markup Language. |
| HDSL | A form of DSL that provides T1 (1.5Mbits/second) or better transfer rates and is meant to displace business T1 connections. HDSL requires much less bandwidth than standard T1 encoding to transfer the same amount of data. |
| HDTV | A new standard of displaying and broadcasting television signals that uses at least twice the scan lines of normal television and a 16x9 aspect ratio, as opposed to the old 4x3 aspect ration of a standard TV set. Japan first used an analog form of HDTV. The United States began with a digital form of HDTV, or DTV. |
| Heap | Most commonly, this is a segment of memory claimed by a program. Within the heap, pieces of memory can be used and freed as needed. Depending on usage, heaps can become fragmented as small pieces of memory are used and freed. In formal computer science terms, a heap is the same as a partially ordered tree. |
| Heatsink | A device that makes contact with a microprocessor (or other object in need of cooling) and removes heat by exchanging it with air in a more efficient manner than the flat surface the heatsink is attached to. The heatsink does this by providing more surface area than a flat surface. This is usually accomplished by having a group of fins built into the shape of the heatsink. The longer the fins, and the more of them, the higher the surface area, and the better the efficiency. Most heatsinks are aluminum for cost and weight reasons. Copper heatsinks are more efficient, but are seldom used because they are much more expensive, heavier, and harder to build. It is common for a fan to be mounted onto a heatsink to increase the efficiency of heat exchange by blowing cooler air through the fins on the heatsink. |
| Heatsink Fan | This is the common combination of a fan attached to a heatsink that is placed in contact with a microprocessor that needs to be cooled. The heatsink draws heat away from the processor, and the fan expedites the removal of the heat by moving air across the heatsink. Faster airflow generally equals better cooling. |
| HEL | This provides software-based emulation of features that are not directly available in hardware. |
| Help Desk | If you've ever worked in an office environment, you may have called the help desk. This is the support organization designed to take care of your computer and phone problems. Help Desk staff work long hours, have a never ending workload, get harassed by everyone, and get crappy pay. |
| Hertz | A rental company, formerly represented by O.J. Simpson. It is also a measure of speed. One Hertz means one cycle per second, so one megahertz (MHz) means one million cycles per second. This is the common measure of speed for processors and electronic activities inside a computer. |
| Heterogeneous Data sources | A data-warehousing term that describes the idea of drawing data from several different (heterogeneous) data sources on different platforms and computers. |
| Heuristics | This describes a set of rules developed to attempt to solve problems when a specific algorithm cannot be designed. For example, if the problem is "When do you eat food?", if you answer, "When I'm hungry" then you would have to eat immediately every single time you were hungry. Instead, we follow heuristics to determine when to eat by gauging our hunger level, the situation we are in, and our ability to get food. As you can imagine, heuristics are very important for solving artificial intelligence problems. |
| Hexadecimal | A base 16 number system where 16 digits are used instead of 10. In addition to the standard base 10 system numbers 0-9, letters A-F are used to represent the numbers 10-15. Thus, a one digit hexadecimal number is a value between 0 and 15 (where F is 15). A two digit hex number is the value between 0 and 255 (represented as 00 and FF in hex, where 00 is 0*16 + 0*1, and FF is 15*16 + 15*1), and so forth. Hexadecimal numbers are often used to represent data because they are easily translatable to base 2 numbers, which are commonly used to apply to the 0 and 1 (off and on) conditions present in electronics, while base 10 numbers are not. |
| Hibernate | This allows computer users to save the contents of their computer's memory to disk before shutting down the PC. When restarted, the contents are read back into RAM and the computer is brought back to the exact state it was in before hibernation was initiated. This is different from sleep mode, where the computer is not fully shut down. |
| Hidden Surface Removal | This tracks the depth of each triangle in a 3D graphics representation, from the perspective of the viewer, to ensure that objects behind other objects in a scene don't appear until the viewer has them in his or her line of sight. This is why you can't see through walls to what lies behind, but why you can play multiplayer Quake and have people at many different areas in a level. |
| Hierarchical relationship | This relationship is one where elements at lower levels are submissive to elements at higher levels. Just think of the military hierarchy, where the General is above a Captain who is above a Private. |
| High bit-rate DSL | A form of DSL that provides T1 (1.5Mbits/second) or better transfer rates and is meant to displace business T1 connections. HDSL requires much less bandwidth than standard T1 encoding to transfer the same amount of data. |
| High Color | The name given to a graphics card setting that can display 16-bit color (65,536 colors). |
| High Definition Television | A new standard of displaying and broadcasting television signals that uses at least twice the scan lines of normal television and a 16x9 aspect ratio, as opposed to the old 4x3 aspect ration of a standard TV set. Japan first used an analog form of HDTV. The United States began with a digital form of HDTV, or DTV. |
| High Performance Addressing | A form of passive matrix LCD display that improves the response time of the display. HPA screens still suffer from the same contrast problems that make passive matrix inferior to active matrix TFT LCD screens. HPA screens are no longer made, as the cost of active matrix LCD screens has dropped. |
| High-Speed SDRAM | A form of SDRAM memory made by Enhanced Memory Systems. It is designed to operate comfortably at speeds of up to 150MHz or higher at CAS 2 latency levels. It was mainly used by overclockers and was a niche product. |
| Hit | When a user requests an HTML document, image, or external object on the World Wide Web, the server records that request as a "hit." The problem with measuring popularity based on "hits" is that webservers, depending on the logging level, count each graphic on that page as a hit. For example, if you look at a page with 5 images on it, some servers count that as 6 hits: one for the HTML page and 5 for the graphics. For this reason "hits" are a questionable measurement of how popular a website actually is. |
| Holographic Storage | This form of storing data uses a three-dimensional array of storage media. Lasers are aligned vertically and horizontally to read or write a specific section of the media. Holographic storage densities should be superior to standard storage techniques because you are using three dimensions to store data instead of two. Think of holographic storage media looking like a stationary cube with lasers moving around it quickly to read data, while normal storage media is on a flat circular surface that spins. |
| Homepage | A page on the World Wide Web (WWW) that is the first page of a website. Usually it is called index.html or index.htm. When you go to a Web address, this is the first page your browser looks for. |
| Honeypot | A system left open and unprotected to entice hackers to break into it. Usually this is done so that system administrators can monitor the methods used to break in, the frequency of attack, or just to throw off attackers from the real goodies. |
| Host | A generic term used to describe a computer or program that makes a resource available, usually over a network. It is often used as a prefix along with other terms, such as host IP or host computer. |
| Host adapter | This term is synonymous with SCSI adapter. It refers to an add-in board, such as a PCI SCSI card, that allows PCs to communicate with SCSI devices. |
| Hosts | A file used by many operating systems, like the LMHosts file, to map IP addresses to host names. It's used mainly for small network installations where there are no WINS or DNS servers on the network to identify host names over the network, or to override such values. |
| Hot Spare | A drive in a RAID configuration that sits idle until one of the RAIDed drives fails. The hot spare then assumes the role of the dead drive. When the dead drive is replaced you can make it the hot spare. (The old hot spare doesn't revert back because it's got data on it now.) Hot spares are most often used in RAID 5 configurations, but can also be used in RAID 1 or RAID 10. When a drive fails the hot spare must be populated with information regenerated from the other drives. During this time performance is degraded. |
| Hot-pluggable | Same as hot-swappable, but also connotes a simple plug-in mechanism for easy swapping. |
| Hot-swappable | This type of mechanism implies that you can remove or add things while the system is powered on and running. For example, hard drives and power supplies are often candidates for this term, but more expensive servers may even have hot-swappable memory, PCI cards, and processors. Normally they come in special proprietary form factors in server machines and RAID boxes. If you've got mission-critical applications, you want your servers to have as many hot swappable components as possible. |
| HPA | A form of passive matrix LCD display that improves the response time of the display. HPA screens still suffer from the same contrast problems that make passive matrix inferior to active matrix TFT LCD screens. HPA screens are no longer made, as the cost of active matrix LCD screens has dropped. |
| HSDRAM | A form of SDRAM memory made by Enhanced Memory Systems. It is designed to operate comfortably at speeds of up to 150MHz or higher at CAS 2 latency levels. It was mainly used by overclockers and was a niche product. |
| HSF | This is the common combination of a fan attached to a heatsink that is placed in contact with a microprocessor that needs to be cooled. The heatsink draws heat away from the processor, and the fan expedites the removal of the heat by moving air across the heatsink. Faster airflow generally equals better cooling. |
| HTTPS | A secure means of transferring data using the HTTP protocol. Typically HTTP data is sent over TCP/IP port 80, but HTTPS data is sent over port 443. This standard was developed by Netscape for secure transactions, and uses 40-bit encryption ("weak" encryption) or 128-bit ("strong" encryption). If you are at a secure site, you will notice that there is a closed lock icon on the bottom area of your Navigator or IE browser. The HTTPS standard supports certificates. A webserver operator must get a digital certificate from a third-party certificate provider that ensures that the webserver in question is valid. This certificate gets installed on the webserver, and verifies for a period of a year that that server is a proper secure server. |
| Hyper Text Transfer Protocol | The way the data in an HTML document is transferred. A document coming in over the HTTP protocol, usually TCP/IP port 80, is read as an HTML document. You may notice in our Internet browser's address bar that the address begins with "HTTP://" in order to tell the browser to expect HTML files. |
| HyperText Markup Language | A standard language initially created for typesetting. Although it is a language, it isn't really a programming language. It is mainly used for creating documents on the World Wide Web. Included in the language are provisions for displaying graphics and links to other pages. |
| Hypertext Preprocessor | Created in 1994, this is a versatile embedded scripting language that can be placed into HTML documents. As long as the webserver supports it, PHP can be used to generate HTML pages by accessing a database. PHP code is executed on the server, and offers an alternative to CGI or SSI calls, or the use of languages such as ColdFusion. |
| HyperTransport | An industry standard serial connection method pioneered by AMD for the internal connection of different buses inside of a PC or network device. It initially allows for connection speeds of up to 6.4GB/second. The first main consumer product using HyperTransport was the NVIDIA nForce2 chipset. AMD's Opteron has up to three HyperTransport links, while the Athlon 64 has one. |
| i-Link | Sony's name for the IEEE 1394, or FireWire, interface. For some reason Sony decided to pick its own name for the IEEE 1394 interface when it is used on Sony's devices. There are no differences between "i-Link" and IEEE 1394. |
| i-Mode | A packet-based means of wireless data transfer used widely in Japan and offered by Japanese mobile phone company NTT DoCoMo. iMode uses CWML (Compact Wireless Markup Language) instead of WAP's WML for data display. i-Mode was introduced in 1999 and was the first method available to browse the Web from a cellular phone. |
| I/O | This abbreviation refers to any operation in a computer where data is transferred in or out of the computer. I/O may seem like a vague concept, but it refers to the basic power of a computer to communicate with the world outside of the box. |
| I2O | The I2O standard was designed to simplify and speed up I/O operations on servers. It was going to eliminate the need for different drivers for each OS, and for each SCSI card and network card. The speed-up was achieved by using an Intel 960 chip on the server's motherboard to handle a lot of the I/O processing that would normally be handled by the processor or I/O subsystem. The I20 SIG disbanded in late 2000, and it's no longer in existence, much like the technology. |
| IA-32 | Intel's 32-bit instruction architecture that runs on the company's 386, 486, Pentium, Pentium Pro/II/III/4, and future consumer chips. |
| IA-64 | Intel's 64-bit instruction architecture that features EPIC and runs on the Itanium processor. It's a fully 64-bit architecture built new from the ground up. |
| IANAL | You may see this abbreviation used in message rooms or chat rooms when people attempt to interpret a situation legally but are not actually lawyers. |
| ICMP | A TCP/IP messaging protocol that runs specifically over IP (as opposed to UDP). This protocol is used to announce network errors, timeouts, and congestion. PING is based on ICMP. |
| ICMP Flood | A type of Denial of Service attack that sends large amounts of (or just over-sized) ICMP packets to a machine in order to attempt to crash the TCP/IP stack on the machine and cause it to stop responding to TCP/IP requests. |
| Icon | A graphic, usually a small one, that represents something, usually a file on the hard drive. Icons can also represent directories, folders, devices, or programs. In a GUI environment, icons can represent just about everything. |
| ICQ | One of the first and most popular instant messaging clients. It was developed by Mirabilis, which was later purchased by AOL. |
| IDE | see Integrated Device Electronics when talking about hard drives and storage devices, and Integrated Development Environment when talking about development tools and programming. |
| IETF | An international group open to the public, generally made up of network designers, operators, vendors, and researchers concerned with the evolution of Internet architecture. The IETF meets three times per year, and does most of its work in smaller groups via mailing lists. The IETF is perhaps most famous for having control of which documents become RFC documents and define interoperability standards or suggested methods of practice for the Internet. |
| IIS | The name for Microsoft's webserver. It works with server versions of Microsoft's operating systems, and was first developed for Windows NT Server. Starting with Windows 2000 Server, IIS ships on the CD. With Windows NT 4 Server you had to install additional software to get IIS installed. |
| Illegal | Within the context of a computer program, this refers to any operation that attempts to access an area of memory or perform an instruction that is not within the rules of the computer architecture or computer programming language. |
| iMode | A packet-based means of wireless data transfer used widely in Japan and offered by Japanese mobile phone company NTT DoCoMo. iMode uses CWML (Compact Wireless Markup Language) instead of WAP's WML for data display. i-Mode was introduced in 1999 and was the first method available to browse the Web from a cellular phone. |
| Impedance | A measure of resistance to electrical current flow when a voltage is moved across something, such as a resistor. Impedance is measured in ohms, and is the ratio of voltage to the flow of current allowed. |
| Import | The process of pulling data into a program. Normally it refers to taking a plain text file and pulling it into a database format so that you can work with it using a database program. For example, you call a company you need some data from and ask it to send you some data to add to your database. The company sends the data as a text file, and you import it into your database. Now you can run queries on the data in your database program. However, you could import any data format your database program supports. There are hundreds out there. |
| Incremental Backup | A method of archiving data. Basically, during an incremental backup all data that has changed since the last full (or previous incremental) backup will be archived; data that has not changed will not be backed up. It is possible to take incremental backups after previous incremental backups, but then if you need to restore something fully you will need all of the incremental data (which may be split over several tapes, for example) and the last full backup. |
| Independent Software Vendor | A software company that creates software to run on a platform or platforms that it doesn't create. For example, Microsoft is not an ISV because it owns its own OS. Often the term refers to companies that write "valuable" software applications. OS makers will often give them sweet deals and help them distribute their software if they feel it benefits their OS. |
| Industry Standard Adapter | The original 8- and 16-bit expansion card standard used in PCs. ISA cards run at a bus speed of 8MHz. You can plug ISA expansion cards into an ISA slot. Modems and sound cards were the last ISA cards due to their low bandwidth requirements. ISA is rarely found on new motherboards nowadays, as it has been replaced by PCI. |
| Infiniband | A standard created by Intel and other server manufacturers to link servers and network devices externally at high speeds. It should scale as high at 30GB/second, but initially will run at 2.5Gbits/second (0.3 GB/second). |
| Information Services | This refers to the field of computer technology, but has been replaced by the newer and sexier term "IT." |
| Information Technology | The field of work dealing with computers and technology, or more specifically, the organization within a company that takes care of all of the computers, telephones, webservers, and Internet connectivity that keeps a company able to communicate with the outside world by electronic means. |
| Infrared | A form of radiation that has a wavelength above that of visible light and below that of microwaves. Infrared radiation has wavelengths between 750 and 100,000 nanometers. Infrared sensors are used in night-vision goggles and sensors. As well, infrared light can be used to send signals wirelessly back and forth between computing devices, but is limited to short line-of-sight communications. |
| InfraRed Data Association | These people developed the IRDA port standard that transfers data through the use of infrared light. Of course, you must have two IRDA devices to get any real use out of this technology. Most notebooks today come standard with this port, as do PDAs and some printers as well. It's handy if you road warriors want to print a document and you've got all the right equipment. |
| Infrared Link Access Protocol | The IrDA has defined this protocol as a means of communication between serial Infrared devices. It's widely supported in PDAs, laptops, and some network printers. |
| Initial Public Offering | When a private company plans to go public (i.e., allows its stock to be traded to the public) it files for an Initial Public Offering with the Securities and Exchange Commission. Once the proper forms are filed and proper requirements are met, the private company agrees to offer a percentage of its company to the public in the form of stock shares, and sets an initial sale price for those shares. The goal of an IPO is to raise a specific amount of money for the company to use to meet a business objective, get the initial stockholders wealth, and/or take a business to the next level. |
| Inkjet Printer | The next generation of dot matrix printers. It uses a head that sprays tiny droplets of ink onto print material. There are three major benefits to this method: 1) it is quieter than standard dot matrix printers, 2) it is able to make smaller dots to make print look better, and 3) since the ink is in liquid form it mixes better when printing in color. On the downside, early models printed slower than standard dot matrix printers, and since they do not print by impact they cannot print carbon copies. Nowadays inkjet printers can easily outpace dot matrix printers. |
| Input | Anything entered into a computer or system. This includes keystrokes, mouse movement, and talking into a microphone. |
| Input/Output | This abbreviation refers to any operation in a computer where data is transferred in or out of the computer. I/O may seem like a vague concept, but it refers to the basic power of a computer to communicate with the world outside of the box. |
| Institute of Electrical and Electronics Engineers | A non-profit organization of engineers that holds conferences, publishes literature, and develops standards for electronics. Its membership spans over 150 countries. One example of its work is the IEEE 1394 standard, also called FireWire. |
| Instruction | The simplest direction that you can give to a processor. Programs are made up of these, but usually don't go down to such nitty-gritty levels unless you are programming in assembly language. An example of what a single instruction would do is increment a piece of data by one, or clear a piece of data out of a register. |
| Instruction Decode Unit | The part of a microprocessor pipeline that decodes instructions that are sent to the microprocessor. It can decode and optimize the order of instructions before it sends them to the execution unit to be run. |
| Int 13h | An interrupt that allows for identification of a hard drive and transfer of data through the ATA/IDE interface. Limitations in the addressing capabilities of Int 13 have caused many problems recognizing hard drives as they get larger. |
| Integrated Circuit | A combination of multiple circuits into a single integrated device. Today the common microprocessor uses many millions of transistors, with each transistor counting as a single circuit. This combination is an integrated circuit. |
| Integrated Development Environment | A development environment that is integrated into an application. For example, many office suite programs feature a macro language that can be expanded by using a common programming language. Specifically, Microsoft Office allows development in Visual Basic for Applications inside of its Office products. Thus, the development environment is integrated into the applications. |
| Integrated Device Electronics | IDE is the standard hard drive interface for PCs. You can connect a maximum of two hard drives to an IDE connection or channel. IDE hard drives are cheaper than SCSI drives, but IDE is generally slower than SCSI and does not support sector re-mapping. |
| Integrated Services Digital Network | A digital line that is often used to connect to the Internet. It generally comes in two flavors: one is a 56Kbps version, which in actuality only uses half of the ISDN line's bandwidth; the other is the 128Kbps version, which uses both the 56Kbps channels on the line. However, that's only 112Kbps--the other 16Kbps are an 8Kbps back channel of each line. |
| Interface | A connection point that allows for interaction between some hardware or software and other hardware or software (or a person). |
| Interlaced | This means that the graphic data is split (usually into two parts), and is displayed alternately line by line. The first pass draws every even line, and then another pass is made to draw every odd line. So for video output, if you have 480 pixel rows shown vertically, an interlaced image will show 240 pixel rows (every other pixel row) at once. It will alternate fast enough that the image looks whole and complete. This is a trick used to increase resolution. However, it makes text and small shapes shimmer in a disturbing way. Standard television signals are interlaced, and that's one reason that text looks awful on a television screen. See also non-interlaced. |
| Interleave | This typically refers to the numbering scheme of sectors of data on hard drives. With an interleave of one, sectors are numbered sequentially. With an interleave of two, sequential data is stored on every second sector, and so forth. The reason for interleaves higher than one is that hard drives cannot always keep up with the spin speed of the disk and sometimes need a break before getting to the next region of data. For example, if the data were listed as 11111 xxxxx 22222 yyyyy (interleave of two) then while the hard drive spins over xxxxx it can take some time and get ready to start reading 22222. If a hard drive read head is quick enough to have an interleave of one, data is simply put sequentially onto the media. |
| Intermediate Code | Code that is generated by the first step in a compiler. Rather than translating code directly from one language to another, compilers first translate it to this more generic and easier to manipulate language and then spit it at the code generator, which creates the finished product. |
| International Standards Organization | These folk create standards for everything, from cleanliness to file formats. |
| International Telecommunications Union | A Swiss organization that decides on international telecommunications standards. An example of its work is the V.90 56K modem standard. |
| Internet Control Message Protocol | A TCP/IP messaging protocol that runs specifically over IP (as opposed to UDP). This protocol is used to announce network errors, timeouts, and congestion. PING is based on ICMP. |
| Internet Engineering Task Force | An international group open to the public, generally made up of network designers, operators, vendors, and researchers concerned with the evolution of Internet architecture. The IETF meets three times per year, and does most of its work in smaller groups via mailing lists. The IETF is perhaps most famous for having control of which documents become RFC documents and define interoperability standards or suggested methods of practice for the Internet. |
| Internet Information Server | The name for Microsoft's webserver. It works with server versions of Microsoft's operating systems, and was first developed for Windows NT Server. Starting with Windows 2000 Server, IIS ships on the CD. With Windows NT 4 Server you had to install additional software to get IIS installed. |
| Internet Message Access Protocol | A standard for retrieving mail that is more advanced than POP3 in that you create folders on the server and those folders will show up in any e-mail client you use. In addition, an IMAP client can do more advanced operations than POP3 when retrieving mail from an IMAP server, such as screening the subject lines before downloading mails. |
| Internet Protocol | A connectionless communications protocol that forms part of the basis for the TCP/IP protocol suite. It is a fast protocol, but it has no mechanism for sequencing or error conditions--error packets are simply lost. IP will basically just move datagrams. TCP and UDP run on top of the Internet Protocol, where TCP is the more robust protocol and UDP is intended for applications that don't require exact quality of service--like voice transmission. |
| Internet Relay Chat | A client/server protocol where IRC clients can connect to an IRC server and "chat." There are several networks of these computers, and there are thousands of channels (or rooms) and hundreds of thousands of people. There is a channel for any interest you could have--it is simply a matter of finding the name. You need to use an IRC client to get to the channels, but as long as you have an Internet connection you can get hooked in. There are also methods of directly transferring files between IRC clients. |
| Internet Server API | An API proposed by Microsoft to replace CGI. Programs written to ISAPI are compiled as DLLs and stored in memory so they can be run faster than CGI scripts--or at leastCGI scripts not using FastCGI or Mod-Perl, which both have similar caching features. |
| Internet Service Provider | A company that provides Internet access to people or corporations. Early ISPs generally had pools of modems awaiting dial-up connections, but many ISPs nowadays only deal in high-end business communications. Smaller ISPs buy bandwidth from larger ISPs. |
| Interrupt request | A means for devices to request time from the processor to do their jobs. For instance, every time you hit a key on your keyboard an interrupt is generated on the keyboard IRQ. This is mainly only a concern for PC users, and IRQs were the bane of existence for many computer builders when ISA cards were more popular. Nowadays IRQ problems can still be a hassle, as you only get 16 of them and many are used already, but devices share IRQs more intelligently. |
| Interstitial Ad | A Web advertisement that pops up in between the viewing of Web pages. See also superstitial ads. |
| IPO | When a private company plans to go public (i.e., allows its stock to be traded to the public) it files for an Initial Public Offering with the Securities and Exchange Commission. Once the proper forms are filed and proper requirements are met, the private company agrees to offer a percentage of its company to the public in the form of stock shares, and sets an initial sale price for those shares. The goal of an IPO is to raise a specific amount of money for the company to use to meet a business objective, get the initial stockholders wealth, and/or take a business to the next level. |
| IPSEC | The IETF standard for "secure IP" transport. Typically IPSEC is used in branch-VPN tunnels between routed LAN segments, but it's destined to become the method for securing IP traffic over IPv6. |
| IPv4 | An outdated version of the IP protocol that is still in use on the Internet. It uses a 32-bit addressing scheme, represented by four 8-bit (0-255) numbers separated by periods, such as 123.3.12.255. The addressing scheme allows for a maximum of about 4.3 billion numbers (256*256*256*256). This gets to be a problem as more and more devices are connected to the Internet. ISPs have taken to using Network Address Translation to get around the problem for now, but IPv6 is the ultimate solution. IPv4 may be with us for a long time, even though it is technically outdated. |
| IPv6 | The current version of the IP protocol that features a 128-bit addressing scheme, as opposed to the 32-bit addressing scheme of IPv4, supporting a much higher number of addresses. It also features other improvements over IPv4, such as support for multicast and anycast addressing. |
| IPX/SPX | A network protocol made famous by Novell's NetWare operating system. It is much more scalable than NetBEUI, but it is not as easy to route as TCP/IP. Thus, IPX/SPX did not become the protocol of choice for the Internet. Most companies have eliminated IPX/SPX from their networks, as TCP/IP has become the network protocol of choice, and current versions of NetWare now support TCP/IP as the default protocol. |
| IRDA | These people developed the IRDA port standard that transfers data through the use of infrared light. Of course, you must have two IRDA devices to get any real use out of this technology. Most notebooks today come standard with this port, as do PDAs and some printers as well. It's handy if you road warriors want to print a document and you've got all the right equipment. |
| IrLAP | The IrDA has defined this protocol as a means of communication between serial Infrared devices. It's widely supported in PDAs, laptops, and some network printers. |
| IRQ | A means for devices to request time from the processor to do their jobs. For instance, every time you hit a key on your keyboard an interrupt is generated on the keyboard IRQ. This is mainly only a concern for PC users, and IRQs were the bane of existence for many computer builders when ISA cards were more popular. Nowadays IRQ problems can still be a hassle, as you only get 16 of them and many are used already, but devices share IRQs more intelligently. |
| ISA | The original 8- and 16-bit expansion card standard used in PCs. ISA cards run at a bus speed of 8MHz. You can plug ISA expansion cards into an ISA slot. Modems and sound cards were the last ISA cards due to their low bandwidth requirements. ISA is rarely found on new motherboards nowadays, as it has been replaced by PCI. |
| ISAPI | An API proposed by Microsoft to replace CGI. Programs written to ISAPI are compiled as DLLs and stored in memory so they can be run faster than CGI scripts--or at leastCGI scripts not using FastCGI or Mod-Perl, which both have similar caching features. |
| ISO | These folk create standards for everything, from cleanliness to file formats. |
| ISO 9000 | This is a certification granted to companies that manufacture goods. It specifies that they have properly recorded all of their procedures and they meet with certain specifications. |
| ISV | A software company that creates software to run on a platform or platforms that it doesn't create. For example, Microsoft is not an ISV because it owns its own OS. Often the term refers to companies that write "valuable" software applications. OS makers will often give them sweet deals and help them distribute their software if they feel it benefits their OS. |
| Iteration | This is a programming term. It refers to a process that can be described by a fixed number of variables and a set of rules that describes what happens to those variables to achieve the next step of the process. If the process is interrupted, it can be continued if the state of all the variables is known. Contrast this to a recursive process. An iteration is a single step. |
| Iterative | This is a programming term. It refers to a process that can be described by a fixed number of variables and a set of rules that describes what happens to those variables to achieve the next step of the process. If the process is interrupted, it can be continued if the state of all the variables is known. Contrast this to a recursive process. An iteration is a single step. |
| ITU | A Swiss organization that decides on international telecommunications standards. An example of its work is the V.90 56K modem standard. |
| Java Directory Access Protocol | The Java answer to LDAP. It really means "Java implementation of the Lightweight Directory Access Protocol." |
| Java Server Page | A specification that uses Java Servlets run on the webserver to generate Web pages that feature dynamic content. JSP is freely available, and a competitor to Microsoft's ASP. |
| Java Servlets | A Java application that is designed to execute on a webserver instead of on the client's computer. Servlets can be used in the same way that CGI programs can to move data between a client and the webserver. |
| Java Virtual Machine | A program that runs under an operating system and interprets Java programs. The Java Virtual Machine ideally will not allow any harm to come to the computer because it has no control of the operating system and acts as if it is a separate computer. Thus, if a malicious Java program were to crash the Java Virtual Machine the operating system would remain stable. Another advantage of this mechanism is that different OSes can have their own Java Virtual Machines that should act identically. Thus Java should be able to be run across different platforms easily with no code changes. In the real world, however, this is not always the case. |
| Javabeans | An object-oriented API created by Sun Microsystems for developers to create re-useable Java applications or components. |
| JBOD | One or more disk drives that form a single volume. However, the information on these disks is not striped in any way or protected--a JBOD is not a RAID. It's usually comprised of leftover drives, and the term JBOD can be used to refer to a volume on a single drive, where anything that's not a RAID is a JBOD. |
| JDAP | The Java answer to LDAP. It really means "Java implementation of the Lightweight Directory Access Protocol." |
| JEDEC | The standardization body of the Electronic Industries Alliance trade association. It was created in 1958 to form discrete semiconductor device standards, and was expanded to include integrated circuits in 1970. Examples of JEDEC's work include the SDRAM and DDR memory standards. |
| Jini | An initiative developed by Sun Microsystems that allows for spontaneous communication and information sharing over a network. |
| Jiro | An open software development frame initially provided by Sun Microsystems that enables the management of network storage systems from different manufacturers and designs. |
| Joint Electron Device Engineering Council | The standardization body of the Electronic Industries Alliance trade association. It was created in 1958 to form discrete semiconductor device standards, and was expanded to include integrated circuits in 1970. Examples of JEDEC's work include the SDRAM and DDR memory standards. |
| Joint Photographic Experts Group | A method of storing graphic images. It was specifically made for storing images with more than 256 colors in a small file size. JPEG files use lossy compression. You can also set the amount of compression you would like for the graphic; however, the higher the compression the less quality the graphic has. On the down side, even at 100% quality (or 0% compression) the graphic is not perfect, already losing some detail (thus the "lossy" compression). JPEG files use the extension ".jpg." |
| Joystick | An input device first found on arcade game machines, then home game systems, and finally on computers. It consists of any stick-like object attached to a base that can be pushed in four or more directions. Usually there's a button in the vicinity of the joystick. Joysticks come in many shapes and sizes, with the typical arcade joystick having a large ball at the top that can be easily gripped; but lately, joysticks have been replaced by cheap button pads in many home gaming systems. However, smaller joysticks that can be pushed around with a single finger have been added to some of the pads as well. |
| JPG | This is the common file extension for a JPEG file. |
| JSP | A specification that uses Java Servlets run on the webserver to generate Web pages that feature dynamic content. JSP is freely available, and a competitor to Microsoft's ASP. |
| Jumper | A jumper fits on two metal connectors. It provides an electrical connection between the two wires to enable a semi-permanent hardware configuration. The Plug-and-Play initiative was designed to help eliminate jumpers, and this is slowly happening. Most hard drives and motherboards still have some jumpers that users can utilize to make the devices act in different ways. |
| Just a Bunch Of Disks | One or more disk drives that form a single volume. However, the information on these disks is not striped in any way or protected--a JBOD is not a RAID. It's usually comprised of leftover drives, and the term JBOD can be used to refer to a volume on a single drive, where anything that's not a RAID is a JBOD. |
| JVM | A program that runs under an operating system and interprets Java programs. The Java Virtual Machine ideally will not allow any harm to come to the computer because it has no control of the operating system and acts as if it is a separate computer. Thus, if a malicious Java program were to crash the Java Virtual Machine the operating system would remain stable. Another advantage of this mechanism is that different OSes can have their own Java Virtual Machines that should act identically. Thus Java should be able to be run across different platforms easily with no code changes. In the real world, however, this is not always the case. |
| K Desktop Environment | The KDE project was started in 1996 by Matthias Ettrich as a way to bring a more user-friendly GUI experience to UNIX users. KDE is an Integrated Desktop Environment for UNIX and Linux that adds functionality to X-Windows. See also Gnome. |
| Karnaugh Mapping | A means of showing the relationship between logic inputs and desired output. Generally a truth table is mapped to a smaller, more workable grid of output values (1s and 0s). Karnaugh Mappings are often used when working with electronic circuits and trying to predict their output. |
| Katmai New Instructions | This is the original code-name for Intel's SSE instruction set, named after the first Pentium III processor core, code-named "Katmai." |
| KDE | The KDE project was started in 1996 by Matthias Ettrich as a way to bring a more user-friendly GUI experience to UNIX users. KDE is an Integrated Desktop Environment for UNIX and Linux that adds functionality to X-Windows. See also Gnome. |
| Kernel | The guts of any operating system. The kernel is loaded into main memory and stays there, while other pieces of the OS are loaded in and out of memory. The kernel controls all requests for disk, processor, or other resources. Generally the smaller and faster the kernel, the faster the operating system will operate. However, larger kernels can provide more functionality. |
| Keyboard | The main input device on most PCs. It consists of a "board" with a set of buttons on it that represent all the letters in the alphabet, the numbers 0 through 9, and any extra keys, like cursor keys and function keys, that enable some keys to represent additional characters. |
| Keyword | A term most often used to describe content on a Web page so that search engines can properly index the page. Keywords are not used any longer by most search engines, as they have been abused too many times by people listing keywords that have nothing to do with their pages in an attempt to get extra traffic. |
| Kilobit | 1024 bits (2^10 bits). |
| Kilobits Per Second | A measure of data transfer. A 56Kbps dial-up modem transfers data at about 7.2 kilobytes (KB) per second, or about 432 KB per minute. |
| Kilobyte | 1024 bytes (2^10 bytes). |
| KNI | This is the original code-name for Intel's SSE instruction set, named after the first Pentium III processor core, code-named "Katmai." |
| KVM switch | A switch that connects two or more computers to the same keyboard, mouse, and monitor. The KVM switch fools each computer into thinking that it is actively connected to a separate keyboard, mouse, and monitor. There is always some mechanism (a button and or keyboard command) on a KVM switch to decide which computer (at a given time) accepts the input of the keyboard and mouse and displays output to the monitor. Thus, when you move the mouse connected to the switch your mouse movement is only echoed to the active computer. Some KVM switches also accept audio input so that more then one computer can use the same set of speakers, although not simultaneously. Most KVM switches use PS/2 ports for keyboard and mouse operations, but more and more are coming with USB support. |
| L1 cache | A small piece of very fast memory that's almost always on the CPU chip itself. It sits between the CPU registers and the L2 cache. Typically L1 cache has a lower latency than L2 cache, making it more expensive to produce and harder to produce in larger quantities without additional complexity. |
| L2 cache | A piece of fast memory that sits between the L1 cache of the processor and main memory. It is usually larger than L1 cache, and the L1 cache checks the L2 cache before going to main memory for data (unless the L1 and L2 caches are unified--see unified cache). Nowadays L2 caches are almost always on the same die as the microprocessor, but they can be off-chip. |
| L3 Cache | This type of cache is becoming more prevalent as microprocessor manufacturers ship more processors with L1 and L2 cache built into the processor. L3 cache is then the extra cache that sits on the motherboard between the processor and main memory, since the processor already contains L1 and L2 cache. Some processors are starting to ship with L3 cache built-in as well to speed up memory operations further. In those cases the L3 cache often sits on a separate area of the die, not built directly into the chip core. |
| Lag | A condition caused by network congestion. When more traffic is flowing than a network or connection can handle, it causes programs waiting to send or receive data over the network to slow down, or lag. This term is often used to describe a slowdown while playing games online, especially over dial-up modems or any connection with high latency. |
| Lapping | The practice of sanding down the surface of a microprocessor package to make it flatter than it was initially in order to make better contact with a heatsink. You do not sand down the microprocessor itself, but the metal surface on the top of the microprocessor that comes into contact with a heatsink. Typically you start with a rougher (but still fine) grit of sandpaper and lightly sand the surface flat, moving to finer and finer sandpaper until the metal has a mirror shine. Uneven chip package surfaces make the microprocessor contact the heatsink poorly. Lapping can be dangerous, especially with newer processors that are smaller than their older counterparts and have less metal on top of them. If you sand through the metal you will ruin the processor. |
| Laptop | A computer small enough to fit completely on your lap. See also notebook. |
| Large Scale Integration | This refers to chips containing thousands of transistors--but less than a million. See also ULSI, VLSI, MSI, and SSI. |
| Laser Pointer | This is typically a pen-shaped device that emits a bright red laser light that appears as a red dot on any surface at which it is aimed. In a smoke-filled room, fog, or other similar environmental conditions, you can see the entire beam and not just the endpoint of the laser. Laser pointers started out as a means for presenters to easily point to specific areas of their presentations on large displays, and as their price came down they evolved into a means to harass people at sporting and other events. Laser pointing devices are also used to target long-range rifles, as the distance a laser light beam can travel without dispersing is quite impressive, and light travels in a relatively straight line unless it is reflected or refracted. Newer pointers also come in green. |
| Laser Printer | A printer that uses a laser to heat up a drum and etch out what is to be printed. Toner goes on this etching and then the toner is heated to bond with the print material. |
| Latency | A measure of how long, on the average, it takes to get a response from something. This term usually refers to network response speed, but can also refer to storage devices (hard drives, CD-ROM drives, etc.). |
| LBA | A form of addressing used by Enhanced IDE to recognize hard drives over 528 MB, as specified in the original IDE standard. LBA literally translates the hard drive's parameters into logical parameters that are able to be recognized by the computer BIOS. |
| LCD Panel | A slab of specially treated glass which is used to sandwich liquid crystal. You can then send electricity through the treated glass to change the phase of the liquid, which then changes color. This technology requires a separate light source, usually a flourescent light, to be easily visible to the user. |
| LCD Projection Panel | This is physically similar to a standard LCD panel except it does not have any back/backlight, so you can put it on an overhead projector and shine a light through it. |
| LCD Projector | A projector designed to display an image from your computer (or consumer video device) onto a large wall or movie screen. LCD projectors use three small, separate LCD screens (red, green, and blue) and shine a bright light through them to generate the image. See also DLP projector. |
| LDT | An interconnection standard introduced by AMD that allows for fast data transfers among the Northbridge part of a chipset, the PCI bus(es), and the Southbridge part. In a multiprocessing machine the LDT bus can transfer data between sets of two processors. AMD now calls this technology HyperTransport. |
| Leased Line | A phone line that can be leased from the telephone company with the assurance that the company using it is the only one on the line, thus giving faster data speeds. These lines are often used to connect different branch locations of companies. |
| LED | This piece of electronics emits light when a current is passed through it. It does not work the same way as a light bulb, so it does not have the problem of burning out. It also only emits a few frequencies of light, so it can be a specific pure color. |
| Legacy device | A type of device or peripheral that is not Plug-and-Play-compatible. Such devices often contain jumpers that must be set manually. |
| Legacy System | Any old computer system that was set up before your time and now continues to work and need support. Often legacy systems are problematic to upgrade because the people that put them together aren't around any more. One great example was the Year 2000 problem. Legacy systems were driving everyone nuts because no one programmed in COBOL anymore, and lots of legacy code was written in COBOL. |
| LFN | A standard introduced by Microsoft with Windows 95 that allowed users to break from the file naming conventions of DOS. DOS only allowed filenames of eight letters then a period then three more letters. Almost all other file systems allow for longer names. They can be 255 characters long, containing spaces or even periods. Besides the 255 character limit the only real restriction is that none of the following characters may be used in filenames: /:*?" |
| License | Most corporations need multiple copies of software, but do not need the media in which they come, either because they already have it or because they allow users to install software from a server on the network. Companies still need to purchase a copy for each user, however, so they need a way to prove they have actually purchased a copy of each. These companies purchase software licenses with no associated media. Such licenses are typically just sheets of paper that cost a lot of money, but allow you to legally use additional copies of the software. |
| Light Emitting Diode | This piece of electronics emits light when a current is passed through it. It does not work the same way as a light bulb, so it does not have the problem of burning out. It also only emits a few frequencies of light, so it can be a specific pure color. |
| Light Pen | A pen-like device that is sensitive to light. More specifically, it is sensitive to the electron gun of a CRT monitor hitting it. Based on when the electron gun hits the light pen, a computer can determine where on a CRT screen the light pen is positioned. Thus, light pens can be used to "draw" on CRT screens, or can be used just like mice or other pointing devices. |
| Lightning Data Transfer Bus | An interconnection standard introduced by AMD that allows for fast data transfers among the Northbridge part of a chipset, the PCI bus(es), and the Southbridge part. In a multiprocessing machine the LDT bus can transfer data between sets of two processors. AMD now calls this technology HyperTransport. |
| Lightweight Directory Access Protocol | An industry standard open client/server protocol for accessing a directory service, such as Active Directory or Novell Directory Services. It is a simplified version of the X.500 protocol. |
| Line out | An analog I/O port for a sound device that allows a device to send a line-level audio signal. This is opposed to an amplified signal on a speaker out port. |
| Linear Tape-Open | An open tape storage standard developed by HP, IBM, and Seagate. The standard consists of two formats: Accelis and Ultrium. Accelis is designed for faster access speed and uses a two-reel 8 mm tape to store up to 25 GB of data natively. Ultrium uses 1/2" tape on a single reel to offer 100 GB of native storage capacity for the initial format, with roadmaps scaling up to 1.6 TB per tape. DDS and DLT are competing standards. |
| Liquid Cooling | This form of cooling refers to water cooling, or any other method of cooling where a liquid is used to keep something cool. |
| Liquid Crystal Display Panel | A slab of specially treated glass which is used to sandwich liquid crystal. You can then send electricity through the treated glass to change the phase of the liquid, which then changes color. This technology requires a separate light source, usually a flourescent light, to be easily visible to the user. |
| LMHosts | A file used by Windows to map IP addresses to NetBIOS computer names. This file is included for compatibility with utilities that support the Microsoft LAN Manager 2.x networking first implemented in early versions of Windows NT. |
| Local Area Network | A small isolated network at one office or physical location. Most office computers are connected to a LAN, but may also be connected to the Internet or a WAN. |
| Log File | A file that records events. Many programs produce log files. Often tech support will ask you to look at a log file to determine what is happening when problems occur. Log files usually record much "grittier" events than are shown to the user, like pieces of Windows 95 starting. You probably don't want to see each part of Windows start, but it's good to have a log of it if something goes wrong. Often log files will have the extension ".log" |
| Logical Block Addressing | A form of addressing used by Enhanced IDE to recognize hard drives over 528 MB, as specified in the original IDE standard. LBA literally translates the hard drive's parameters into logical parameters that are able to be recognized by the computer BIOS. |
| Logical Parity | This is fake parity that always agrees. In other words, when something checks to see if the data is correct logical parity always responds, "Yes!" |
| Logical Unit Number | A term used in the context of devices connected to a SCSI controller. Each device on a SCSI controller has a SCSI ID, but each SCSI ID may have several LUNs that translate to several hard disks or removable media. |
| Long File Name | A standard introduced by Microsoft with Windows 95 that allowed users to break from the file naming conventions of DOS. DOS only allowed filenames of eight letters then a period then three more letters. Almost all other file systems allow for longer names. They can be 255 characters long, containing spaces or even periods. Besides the 255 character limit the only real restriction is that none of the following characters may be used in filenames: /:*?" |
| LongRun | This is Transmeta's term for the ability of its Crusoe microprocessors to operate at lower MHz speeds and voltages if high processor speeds are not required to do a set amount of work. If repetitive tasks are done, the Crusoe architecture will figure out an efficient way to accomplish the tasks and tune down the processor, if it can, to reduce power consumption. Transmeta's favorite example when the technology was introduced was optimization of DVD playback. |
| Low Voltage Differential | The common slang form for "Ultra2 Wide SCSI (LVD)." LVD refers to the Low Voltage Differential interface used in Ultra2 and Ultra3 SCSI. |
| LPT Port | The 25-pin parallel port on a PC. DOS and 16-bit Windows used the LPT designation, as did 16-bit NetWare clients, to send print jobs to a specific physical or logical parallel port. |
| LPX | A motherboard form factor specification that has now been replaced by the NLX specification. LPX is similar to the AT form factor, but expansion boards are inserted into a riser board that usually only allows for two or three expansion cards that are inserted parallel to the motherboard instead of perpendicular. |
| LSI | This refers to chips containing thousands of transistors--but less than a million. See also ULSI, VLSI, MSI, and SSI. |
| LTO | An open tape storage standard developed by HP, IBM, and Seagate. The standard consists of two formats: Accelis and Ultrium. Accelis is designed for faster access speed and uses a two-reel 8 mm tape to store up to 25 GB of data natively. Ultrium uses 1/2" tape on a single reel to offer 100 GB of native storage capacity for the initial format, with roadmaps scaling up to 1.6 TB per tape. DDS and DLT are competing standards. |
| LUN | A term used in the context of devices connected to a SCSI controller. Each device on a SCSI controller has a SCSI ID, but each SCSI ID may have several LUNs that translate to several hard disks or removable media. |
| LVD | The common slang form for "Ultra2 Wide SCSI (LVD)." LVD refers to the Low Voltage Differential interface used in Ultra2 and Ultra3 SCSI. |
| M2020 riser | This board holds a Pentium Pro processor and fits into a Slot 1 slot on a motherboard. This provided backwards-compatibility for Pentium Pro chips with newer Pentium II motherboards. |
| MAC Address | A unique 128-bit address of a network card or device. The first part of the address is unique to the company that produced the device, and beyond that it is a sequence of digits unique to a single device manufactured by a company. |
| Macro | A means of executing a group of instructions within a program. Many programs offer the capability to put together macros so that you don't have to do the same group of repetitive instructions one by one. You can program the macro to do any number of instructions. Many programs allow you to extend the simple macro languages that they provide with other, more complex programming languages. |
| Macrovision | A method of copy protection that rapidly modulates colorburst signals and pulses the vertical blanking signal in order to make videotaped copies of protected materials unwatchable. Some older VCRs even have trouble viewing Macrovision-protected movies. DVD players typically have Macrovision circuits built-in to make copying of DVD movies impossible; however, some DVD players allow Macrovision to be disabled. |
| Magnetic RAM | A form of memory that stores information magnetically instead of electrically like DRAM. IBM has been working on developing MRAM since 1974, and has recently touted it--along with German memory-maker Infineon--as a viable main memory competitor that will be faster than DRAM and able to hold as much information, without requiring the electrical refresh of DRAM--it will hold onto data like Flash memory. |
| Magnetic stripe | A piece of plastic coated with ferromagnetic particles to hold a magnetic flux. In human speak: a strip of audiotape glued onto a card to hold a bit of information. Every credit card has one on the back--it's the black/brown stripe. It usually holds the stuff that's imprinted on the card, like the account number and the expiration date. |
| Magnetic stripe unit | A device to read and encode cards with a magnetic stripe. |
| Mainframe | Basically a large and powerful computer designed to be very fault tolerant. Historically, mainframes with lots of memory and disk space are hooked to a bunch of dumb terminals that can be used to access data and run programs on the mainframe, but can do nothing without the mainframe. See also Client/Server. |
| Management console | Under SNMP, the management console is the computer or device that collects SNMP messages and stores them in the MIB. |
| Management Information Base | When SNMP devices send SNMP messages to the management console, it stores information in this file or database. The MIB collects and contains information on managed objects. |
| Management Information Systems/Services | The department at most companies that everyone loves to hate. MIS people are the people who work with Information Technology, now more commonly referred to as the IT department. |
| Master | When two IDE or EIDE devices are put on the same cable, one must be master and the other slave. The master/slave configuration is used not only to allow communications to work properly for two devices on one channel, but also so that there is a specific boot order when two or more IDE hard drives are encountered on a system. The master hard drive on the first IDE channel will be the first IDE drive checked for a master boot record when the system attempts to boot from an IDE device. |
| Master Boot Record | The first sector on a hard disk or other disk media. When a computer boots up it searches for a master boot record wherever the BIOS tells it to (usually the master hard drive on the first IDE channel, but this can also be checked for in CD/DVD drives and floppy drives) and, based on what the master boot record says, loads up an operating system. Thus, if the master boot record becomes corrupt or is tampered with by a virus, it can cause your computer to be unable to boot. |
| Matrix Math Extensions | 64 additional instructions for matrix math operations that are commonly used to process multimedia data. This was a slight improvement of the Pentium chip design that was supposed to make it easier and faster to deal with video and audio. The improvements weren't very great, however, and this led Intel to develop the SSE instruction sets. |
| Maximize | In a graphical OS, this is the act of clicking on the maximize button of an active window and causing it to cover the entire screen so that the desktop and other running programs cannot be viewed. |
| Maximum Transmission Unit | The largest size of a data packet that can be sent over a TCP/IP or other packet- or frame-based network. Ethernet uses an MTU of 1,500 bytes, while the standard Internet MTU is 576 bytes. Using a higher MTU is recommended for fast networks, while slower or more congested networks need a smaller MTU, as there is a greater chance that not all of the packet will make it through in one shot. Of course, using a small MTU on a fast network causes a lot of extra traffic to be generated, as the packet has to be split into smaller pieces with more conversations for data to be transmitted. |
| Mbit | This is roughly one million bits, or more exactly, 1,048,576 bits (that's 2^20 bits). |
| MBR | The first sector on a hard disk or other disk media. When a computer boots up it searches for a master boot record wherever the BIOS tells it to (usually the master hard drive on the first IDE channel, but this can also be checked for in CD/DVD drives and floppy drives) and, based on what the master boot record says, loads up an operating system. Thus, if the master boot record becomes corrupt or is tampered with by a virus, it can cause your computer to be unable to boot. |
| MCA | A 32-bit standard developed by IBM for expansion cards. The standard offered improvements over 16-bit ISA, but never caught on outside of IBM computers. The industry chose to go with EISA, which was only found in servers and workstations for the most part and was eventually replaced by PCI. |
| MCGA | A graphics standard prior to VGA which allows 320x200 resolutions with 256 colors, or 640x400 resolutions with two colors. It is a bit better than CGA. |
| MCSE | A certification program offered by Microsoft. To become an MCSE you must pass a series of standardized tests at Microsoft-approved testing facilities. On the positive side, the MCSE certification is designed to give employers an easier way of screening candidates. On the negative side, a candidate with an MCSE and little practical knowledge may unfairly receive consideration over a more qualified non-MCSE. Some Geeks think it's worthy to aspire to be an MCSE, but others think it's just a waste of time and money to learn the "Microsoft way." |
| MDF | A type of particle board that is often used in the construction of subwoofer enclosures. It is used due to its ability to absorb vibration and its sturdiness. The best MDF is 3/4" or thicker. |
| MDRAM | A form of graphics RAM created by MoSys that allows transfers of up to 1GB/second. Tseng Labs' popular ET6000 2D graphics chipset used this form of graphics RAM to help achieve its high performance in its day. |
| Mean Time Between Failures | A time normally given in hours that predicts the failure rate of a device. The larger the number the better. |
| Mechanical Control | A dial or knob whose physical setting directly affects some measurement. For example, the power button in early PCs was a mechanical control, as were the huge, hand-controlled electrical switches in old horror movies and light switches on your wall. By pushing the power button you used to physically make an electrical contact so that power could flow to your PC. Nowadays most power buttons only send signals to the motherboard and are no longer mechanical controls. |
| Media Access Control Address | A unique 128-bit address of a network card or device. The first part of the address is unique to the company that produced the device, and beyond that it is a sequence of digits unique to a single device manufactured by a company. |
| Medium Density Fiberboard | A type of particle board that is often used in the construction of subwoofer enclosures. It is used due to its ability to absorb vibration and its sturdiness. The best MDF is 3/4" or thicker. |
| Medium Scale Integration | Chips containing hundreds of transistors, but not thousands. See also ULSI, VLSI, LSI, and SSI. |
| Megabit | This is roughly one million bits, or more exactly, 1,048,576 bits (that's 2^20 bits). |
| Megabits per second | a.k.a. Mbps. This is a measure of throughput roughly in millions of bits per second. More exactly, that is 2^20 (1,048,576) bits per second. |
| Megabyte | This is roughly one million bytes. This is exactly 1,048,576 bytes (that's 1024 x 1024, or 2^20). |
| MegaFlop | The ability of a system to compute one million floating point operations in one second. |
| Megahertz | One million hertz, or one million cycles per second. |
| Megapixel | One million pixels. This term is most often used when talking about how fast 3D graphics cards can pump data to the display device, or how much data a digital camera can capture. As a general rule higher megapixel ratings typically equate to higher maximum performance for graphics, or better quality pictures for digital cameras. See also gigapixel. |
| Memory | Chips in a computer that remember data. Also commonly referred to as RAM. |
| Memory leak | A condition where a program continues to request more memory from an operating system and doesn't tell the operating system when it is no longer using the memory. Programs with memory leaks can end up using all of the memory available, or at least enough to cause performance problems. Memory leaks in programs are fixed by using proper memory management techniques. |
| Message Transfer Agent | In the X.400 Message Handling System this is a program that stores and forwards messages between different mail systems. |
| Messaging API | Originally developed by Microsoft, this allows Windows applications to use the Windows e-mail system using a standard programming interface. Thus any Windows application can more easily use e-mail in Windows. |
| Metal-Oxide-Semiconductor Field-Effect Transistor | A transistor with a source and drain region kept apart by a gate. A voltage applied to the gate controls the flow of electrons from the source to the drain. MOSFETs are used to amplify electrical signals. |
| Metropolitan Area Exchange | A large Internet traffic switching station where ISP backbones meet and traffic moves between them. The two major MAE exchanges are MAE-East and MAE-West, located in the east and west coasts of the United States. MAE-East actually resides inside a parking garage, and had been known at one time to carry about one-third of the traffic on the Internet. In addition to the major MAE points, there are several smaller meeting points. The MAE points were developed by MFS Communications, but are now owned by MCI WorldCom. |
| Metropolitan Area Network | A collection of several LANs that are linked by faster backbone connections. A MAN is smaller than a WAN, and an example is a college campus with several LANs linked on the same network. |
| MFC | A library of C++ functions provided by Microsoft that allows developers to more easily work with Windows operating systems. |
| Mflop | The ability of a system to compute one million floating point operations in one second. |
| MHz | One million hertz, or one million cycles per second. |
| MIB | When SNMP devices send SNMP messages to the management console, it stores information in this file or database. The MIB collects and contains information on managed objects. |
| Mic | see micron or microphone |
| Mic in | An analog I/O sound port that accepts a microphone. If you want your computer, laptop, or sound device to be able to record your voice, it must have a mic-in port, or a built-in microphone. |
| Micro Channel Architecture | A 32-bit standard developed by IBM for expansion cards. The standard offered improvements over 16-bit ISA, but never caught on outside of IBM computers. The industry chose to go with EISA, which was only found in servers and workstations for the most part and was eventually replaced by PCI. |
| Microchip | Synonymous with microprocessor. This term is commonly used to describe the CPU. More specifically, it refers to the part of the CPU that actually does the work, since many CPUs now contain L1 and L2 caches on-chip. |
| Microcomputer | The older term for a common home computer, or single processor computer. The next step up is a workstation. |
| Microcontroller | This is like a scaled-down computer designed for a very specific task, unlike a desktop computer, which has many uses. An example of an application for a microcontroller would be a traffic light, or the chip that controls the suspension system of your new car. |
| Micron | The length of one millionth of a meter, or 1/1,000,000 meters. This length is also referred to as a micrometer. There is also a microchip company called Micron. See also nanometer. |
| Micron Process | The size of lines capable of being etched onto a chip. A fabrication plant with a .25 micron process can create smaller chips that consume less power, and can run faster than a fab with a .35 micron process. |
| Microphone | A device that changes audio into an electric signal. You can plug a microphone into most sound cards, and they are required for certain operations, such as Internet telephony. |
| Microphone Cable | An analog audio cable normally used to connect microphones to professional audio devices. It has three pins and provides a balanced input, as opposed to an unbalanced or single-ended RCA connector. |
| Microprocessor | This term is commonly used to describe the CPU. More specifically, it refers to the part of the CPU that actually does the work, since many CPUs now contain L1 and L2 caches on-chip. |
| Microsoft Certified System Engineer | A certification program offered by Microsoft. To become an MCSE you must pass a series of standardized tests at Microsoft-approved testing facilities. On the positive side, the MCSE certification is designed to give employers an easier way of screening candidates. On the negative side, a candidate with an MCSE and little practical knowledge may unfairly receive consideration over a more qualified non-MCSE. Some Geeks think it's worthy to aspire to be an MCSE, but others think it's just a waste of time and money to learn the "Microsoft way." |
| Microsoft Foundation Class | A library of C++ functions provided by Microsoft that allows developers to more easily work with Windows operating systems. |
| Mid Tower case | A metal (or metal-framed plastic) box about two feet high that has special fittings to hold computer components like a motherboard, power supply, hard drives, and such. |
| Middleware | Software that is used to tie an application to a network, thus the "middle" terminology. Often the middleware is a type of network authentication or directory of network resources. When Microsoft bundled Internet Explorer into Windows IE began acting as middleware for many operations, and that was the crux of the Department of Justice's anti-trust case. |
| Millions of Instructions Per Second | A rating of how quickly a processor can process instructions. A processor rated at 100 MIPS can process 100,000,000 instructions per second. Although it seems straightforward enough, for an accurate comparison you must define which instruction(s) you are going to run, and a rating such as this could lead processor makers to build chips that have high MIPS ratings but aren't useful in the real world. |
| Millisecond | One thousandth of a second. It is often associated with the access speed of hard drives. |
| Minicomputer | This term refers to "mini" mainframe computers that are a step smaller than a large corporate mainframe. They were once popular in small businesses that couldn't afford real mainframes, but now you only find reference to them in free subscription surveys for computer industry print magazines ("Do you work with mini-computers, microcomputers, etc.?") or in some college campuses or large business networks. |
| Minimize | In a graphical OS this is the act of clicking on the minimize button of an active window and causing it disappear from view, or appear in a smaller form somewhere on screen. When minimized, programs continue operating in memory, but allow other windows or the desktop to be viewed. |
| MIP Mapping | Multum in Parvam literally translates to "many in few." This stores a copy of the bitmap used as a texture in different sizes to minimize the distortion caused by shrinking or enlarging the textures during perspective correction. |
| MIPS | A rating of how quickly a processor can process instructions. A processor rated at 100 MIPS can process 100,000,000 instructions per second. Although it seems straightforward enough, for an accurate comparison you must define which instruction(s) you are going to run, and a rating such as this could lead processor makers to build chips that have high MIPS ratings but aren't useful in the real world. |
| Mirror | This can refer to many things in the land of technology. Most often it is used to describe a method of redundancy where data is mirrored across two devices, whether they are physically separate devices or not. Basically the same data is written to both devices, so if one device fails the other can be used and the data will be intact. As far as disk drive redundancy is concerned, when drives are mirrored they are in a RAID 1 configuration. See RAID 1 for more info. |
| MIS | The department at most companies that everyone loves to hate. MIS people are the people who work with Information Technology, now more commonly referred to as the IT department. |
| Mission Critical Application | Any application that is critical to the proper running of a business. If this application fails for any length of time you may be out of business. For example, an order-entry system may be considered mission critical if your business relies on taking lots of orders. You don't want your mission critical apps running on junky hardware ... or software for that matter. |
| MMC | A postage stamp-sized Flash memory card that allows data to be saved onto it. MMC cards are a means of exchanging data between PDAs, phones, digital cameras, and other devices, but they can also serve the function of acting similar to a hard drive on a PC for the storage of data and programs. The MMCA (MMC Association) was founded in 1998 to push the MMC standard. |
| MMX | 64 additional instructions for matrix math operations that are commonly used to process multimedia data. This was a slight improvement of the Pentium chip design that was supposed to make it easier and faster to deal with video and audio. The improvements weren't very great, however, and this led Intel to develop the SSE instruction sets. |
| Modal dialog | A dialog box or window that must be responded to before operation of a program can continue. Modal dialog boxes are easier to program than modeless dialog boxes since you don't have to account for as many conditions. However, modal dialog boxes are generally annoying to users, and should be used only when user input is absolutely required before program operation continues. Overuse of modal dialog boxes will elicit groans of "Why can't I click on that now!?!?" |
| Modem pool | A group of modems that answer calls at a single phone number and connect callers to a specific resource. ISPs use modem pools to connect callers to the Internet. You call a single number and are forwarded to any one of a group of modems. Many offices use modem pools to connect callers to the LAN or WAN. Usually a phone switch takes care of the actual "pooling" of modems. Thus if one modem is busy, it forwards calls to the next one. |
| Modulator/Demodulator | A device that serves as a bridge between your digital computer and some form of analog line used to transmit data, such as a phone line (standard modem) or analog cable connection (cable modem). The modem can receive the analog signals from the line and turn them digital, or transmit your digital signals into analog signals that are capable of being decoded digitally. |
| Moir� (pronounced mor-ay, accent on second syllable) - A graphic effect that puts an undesirable pattern composed of small dots placed in a tight pattern on a plain image. When monitors focus too tightly certain colors will appear to have patterns on the | A device for viewing the output from a computer, usually on a large glass screen, whether it's CRT, LCD, or otherwise. |
| Moore's Law | Former Intel chairman Gordon Moore is credited with predicting the trend that transistor counts in processors double every 18 months. This law has held true since the 1970s. The law can also be applied to other technologies, and works frighteningly well with hard drive and memory chip density, processor speeds, processor power, and processor size (micron process). More than ever the end of Moore's Law is being discussed, as smaller, more compact designs and electrical leakage threaten to throw Moore's Law off track. |
| MOSFET | A transistor with a source and drain region kept apart by a gate. A voltage applied to the gate controls the flow of electrons from the source to the drain. MOSFETs are used to amplify electrical signals. |
| Motherboard | The large circuit board into which your CPU, memory boards, and peripheral cards are plugged. |
| MotherGlass | Thin sheets of glass that LCD screens are cut out of. Manufacturers have periodically increased their production lines to handle larger sheets of motherglass to more efficiently create larger LCD screens. |
| Mount | This term comes from the days when tape media had to be physically mounted at the instruction of an operating system. The terminology is still used in UNIX/Linux environments. When the system is powered on all hard drives are normally set to mount automatically, but removable media such as CD-ROMs and floppy disks have to be manually set to be recognized by the operating system (mounted) after they are inserted into the computer. Some newer GUI UNIX/Linux interfaces will mount media for you automatically and save you the trouble of typing in a potentially complex mount command. |
| Mouse | A pointing device that is pushed around a desk area with the palm of your hand. Traditionally mice have used roller balls to detect motion, but newer models feature no moving parts and use integrated circuits that detect movement over the desktop and translate that into motion. |
| Mousepad | A pad that has a surface made for providing traction for a mouse that uses a roller ball. |
| Moving Pictures Expert Group | An ISO group that works to develop standard formats for compressing video. The standards associated with the group include MPEG-1, MPEG-2 (used in DVD movies), and MPEG-4 (used sometimes to further compress DVD movies onto CD-ROM media). There are other MPEG standards as well. MPEG standard are typically not open standards, and require licensing fees. MPEG files in Windows often have the ".mpg" file extension. |
| Mozilla | An Open Source project put together to create the next generation of Netscape Web browsers starting after Netscape Navigator 4.x. The project is run by developers who work for Netscape, but development is done by both Netscape employees and independent developers. |
| MP3 | A compression standard for audio. It enables compression of CD-audio by about 10 times, depending on the bit and sampling rate. It does not stand for MPEG-3, but rather it is the audio part of the MPEG-1 audio/video compression standard. |
| MPEG | An ISO group that works to develop standard formats for compressing video. The standards associated with the group include MPEG-1, MPEG-2 (used in DVD movies), and MPEG-4 (used sometimes to further compress DVD movies onto CD-ROM media). There are other MPEG standards as well. MPEG standard are typically not open standards, and require licensing fees. MPEG files in Windows often have the ".mpg" file extension. |
| MPEG-1 | An audio/visual compression standard designed by MPEG for devices that can read or write about 1.5 Mbits/second worth of data. |
| MPEG-2 | An audio/visual compression standard designed by MPEG for devices that can read or write about four Mbits/second worth of data. |
| MPR | A standard for levels of electromagnetic field emissions by computer monitors published by the Swedish National Board for Measurement and Testing. Monitors must have electromagnetic field emissions below certain levels to meet MPR standards. |
| MPR II | A newer version of the Swedish MPR electromagnetic field emission standards. It has much more stringent requirements, and CRT computer monitors meeting this standard are presently considered to be safe. |
| MRAM | A form of memory that stores information magnetically instead of electrically like DRAM. IBM has been working on developing MRAM since 1974, and has recently touted it--along with German memory-maker Infineon--as a viable main memory competitor that will be faster than DRAM and able to hold as much information, without requiring the electrical refresh of DRAM--it will hold onto data like Flash memory. |
| MSI | Chips containing hundreds of transistors, but not thousands. See also ULSI, VLSI, LSI, and SSI. |
| MTA | In the X.400 Message Handling System this is a program that stores and forwards messages between different mail systems. |
| MTBF | A time normally given in hours that predicts the failure rate of a device. The larger the number the better. |
| MTU | The largest size of a data packet that can be sent over a TCP/IP or other packet- or frame-based network. Ethernet uses an MTU of 1,500 bytes, while the standard Internet MTU is 576 bytes. Using a higher MTU is recommended for fast networks, while slower or more congested networks need a smaller MTU, as there is a greater chance that not all of the packet will make it through in one shot. Of course, using a small MTU on a fast network causes a lot of extra traffic to be generated, as the packet has to be split into smaller pieces with more conversations for data to be transmitted. |
| Multi User Domain | This is also known as Multi-User Dungeon, but that is a misnomer. A MUD is a world created and that exists solely for the interaction of people within it. MUDs often have themes, but the basis is simply that there is a world detailed by words that you, as a character, can navigate through and interact with other characters. For many early Internet users this is the most addictive part of the Internet. Nowadays most people prefer the graphical interface of commercial programs that provide a world where less reading--and imagination--is required. |
| Multi-Threaded | Some operating systems allow multiple parts, or threads, of a single process to run simultaneously. These OSes are referred to as multi-threaded. UNIX is a multi-threaded OS, as is Windows NT/2000/XP. Multi-threading was added to Linux in 1999 with kernel version 2.2, and refined more in kernel 2.4 in 2001. |
| Multi-tier client server | A form of client/server application that uses the multi-tiered architecture. |
| Multi-tiered architecture | This is the most scalable application architecture (over two-tier and three-tier). This architecture refers to 4-, 5-, or even higher-tiered architectures. It is the most complex type of architecture, splitting the application and database management tasks into many discrete components. For example, take the three-tier architecture and change it so that the application logic is separate from the database management system--this gets you to four-tier architecture. With this structure you can more easily change one of the tiers without compromising your entire application. To get to 5 tiers you could move some of the application logic to the client to optimize performance. |
| Multibank DRAM | A form of graphics RAM created by MoSys that allows transfers of up to 1GB/second. Tseng Labs' popular ET6000 2D graphics chipset used this form of graphics RAM to help achieve its high performance in its day. |
| Multicast IP | A form of TCP/IP being proposed that will allow for high-bandwidth transmissions (like television channels) to be broadcast over the Internet to all the routers in the world (possibly) that are connected to someone watching that channel. To see the benefit, think of 1,000 people making separate connections to the USA network (if it were an Internet TV channel--give us some leeway!). Each packet of data sent out would have to be sent to 1,000 people. Thus, you have 1,000 conversations active among the USA network server and people's machines, each one saying the same thing. That's poor scalability. Now imagine that in this fantasy network we only have 10 routers with these 1,000 people connected to them. In simplistic terms, you only have to send each packet to 10 places, and each machine downloads packets directly from the router it is connected to. Thus the USA network server doesn't have to do much work to keep Gary Busey movies going to 1,000 people at once, and the rest of the network isn't clogged with all 1,000 conversations. However, there are lots of minute details that must be considered, such as how many channels are offered and how much router memory that takes. How about if no one is watching? That's wasted traffic. |
| MultiColor Graphics Array | A graphics standard prior to VGA which allows 320x200 resolutions with 256 colors, or 640x400 resolutions with two colors. It is a bit better than CGA. |
| Multihomed | A machine with more than one NIC attached to more than one network. If a machine has multiple NICs but is only attached to one network, it is not multihomed. A machine must have more than one network attached to be multihomed. The standard home version of a multi-homed machine is one that connects to the Internet and separately to a local network. |
| Multimedia | Any use of audio or video in a computer. In simplest terms this refers to the basic functions of sound cards and video cards. The term also covers television and video integration in computers. |
| MultiMedia Card | A postage stamp-sized Flash memory card that allows data to be saved onto it. MMC cards are a means of exchanging data between PDAs, phones, digital cameras, and other devices, but they can also serve the function of acting similar to a hard drive on a PC for the storage of data and programs. The MMCA (MMC Association) was founded in 1998 to push the MMC standard. |
| MultiMedia Extensions | 64 additional instructions for matrix math operations that are commonly used to process multimedia data. This was a slight improvement of the Pentium chip design that was supposed to make it easier and faster to deal with video and audio. The improvements weren't very great, however, and this led Intel to develop the SSE instruction sets. |
| Multiple Virtual Storage | An IBM mainframe operating system. The term MVS is used to describe an entire family of mainframe operating systems. The term "multiple virtual storage" refers to the use of multiple virtual memory areas in the operating system. |
| Multiplexer | A logic circuit that sends one of several inputs out over a single output channel. In the network world it is used to describe devices that send several signals over a single line at the same time. The device on the other side of the wire that receives the signal is a demultiplexer. |
| Multipurpose Internet Mail Extensions | Functions used for the attachment of binary files to an e-mail message. MIME is the most common group of functions used to make this translation, and allows us to tack on graphics, sound, and executable files to our e-mail messages. |
| Multitasking | The ability of an operating system to run two or more tasks at once. With one processor you will not normally have more than one task using the processor at a given moment in time, but the tasks will be scheduled so that they can all appear to be running at the same time and do not interfere with one another. A task can be a program (e.g., the Windows Calculator) or an instance of a program (e.g., opening the Windows Calculator multiple times). |
| Multum in Parvam Mapping | Multum in Parvam literally translates to "many in few." This stores a copy of the bitmap used as a texture in different sizes to minimize the distortion caused by shrinking or enlarging the textures during perspective correction. |
| MUNG | A recursive acronym that refers to tweaking something until it is so tweaked that it is broken. It is pronounced, and sometimes referred to, as "munge," which rhymes with grunge. |
| Munge | A recursive acronym that refers to tweaking something until it is so tweaked that it is broken. It is pronounced, and sometimes referred to, as "munge," which rhymes with grunge. |
| Musical Instrument Digital Interface | The way to connect musical instruments (traditionally an electronic piano keyboard) to your computer. To connect them to your computer you need a MIDI cable and a MIDI port. The MIDI port usually doubles as a game controller port on your sound card. Instead of recording the sound that comes from the instrument, it records the notes that are played. This can then be played back in a number of ways: its speed can be changed or its tone can be changed. The most interesting aspect is that it can be applied to different instruments. |
| Mux | A logic circuit that sends one of several inputs out over a single output channel. In the network world it is used to describe devices that send several signals over a single line at the same time. The device on the other side of the wire that receives the signal is a demultiplexer. |
| MVS | An IBM mainframe operating system. The term MVS is used to describe an entire family of mainframe operating systems. The term "multiple virtual storage" refers to the use of multiple virtual memory areas in the operating system. |
| MX Record | A record that exists on a DNS server and tells e-mail servers where to send mail for any particular DNS entry. The address is prefaced by a precedence number; for example, "10 mailserver.geek.com" could be an MX record that tells an external e-mail server to try sending mail to the address "mailserver.geek.com." You can have several MX records per domain with different precedence. For example, assuming you have the MX record we just mentioned listed for your domain, you may point to your backup mail server at "5000 backupmail.geek.com" in case your main mail server is down. Of course you could use any number over 10, but a higher number ensures that no mail will go to the backup server unless your main mail server is inaccessible. You can also set a group of e-mail servers with the same number so that traffic will be equally dispersed among them. This is useful if you get a lot of e-mail and need to balance the load. |
| n-tuple | Pronounced "en-too-pull." This is a mathematical term for a finite sequence of n terms. For example, the set {1, 2, 3, 4} is a four-tuple. The set {Frank, Jane, Ed} is a three-tuple. Any time there is a list of n things in a certain order, you can think of it as an n-tuple. |
| N-Way | A method of multiprocessing where each processor runs separate tasks with no special programming required. This is different from SMP, where one task can run across several processors and all processors must act together, requiring special programming to speed up specific tasks. The "N" stands for a number greater than one, where a system with two microprocessors would be a Two-Way system, and so on. |
| Nagware | This is shareware that has screens that pop up and require you to press a button or wait an amount of time. These nag screens go away after you pay for the software and enter a registration code. |
| NAK | The opposite of ACK. NAK is a slang term that means that you disagree, or do not acknowledge something. This also refers to the 21st ASCII character. |
| Nameserver | A server that runs Domain Name Services. |
| Nanometer | One billionth of a meter or 1/1,000,000,000 meters. See also Micron. |
| Nanosecond | One billionth of a second. Used most often to measure the speed of memory. |
| Nanotechnology | The purposeful manipulation of matter at the atomic level to achieve a defined goal. Atomic constructs can be measured in nanometers. Someday nanotechnology may be used to send a group of tiny machines into your bloodstream and free up clogged arteries, or a bunch of tiny nano-war machines could be built and unintentionally change the entire earth into a gray blob of nano-devices. |
| Napster | The most infamous file swapping utility/company. The Napster client allows you to connect to Napster servers and download MP3 files, or allows your own MP3 files to be downloaded by others. The popularity of Napster erupted into lawsuits brought by the RIAA and various recording artists. The actual Napster company had its assets sold off to the highest bidder, but the client lives on through Open Source projects like OpenNap. |
| Narrow SCSI | The original form of SCSI, using 50 pins and transmitting data at 5MBps. See also Wide SCSI. Drives and adapters that support Narrow SCSI usually have an "N" in the part number. |
| NAS | The use of specialized devices that function simply as hard drives connected to a network. NAS devices typically consist of one or more hard drives in a housing that contains a simple operating system and a network connection. The use of NAS devices allows for cheaper and more easily expandable storage without requiring more complex and expensive multi-purpose servers to do the work of delivering files to network users. |
| NAT | A method that many ISPs use to extend their IP addressing to support more addresses than they own. The interior network uses one addressing scheme, and the exterior network uses the standard IPv4 Internet addressing. NAT devices can be routers, firewalls, or proxy-servers. To program a NAT device you must supply translation rules for how interior IP addresses are displayed to the outside world. You could, for example, set your firewall to act as if all traffic coming from inside your corporate network was coming from the firewall's IP address. |
| National Television Standards Committee | A group that is responsible for setting the standard for broadcast and reception of analog television signals in the United States and Japan. The original NTSC standards were set in 1953, and call for 525 horizontal lines of resolution, interlaced scanning, and a 60Hz refresh rate. That standard continues to exist until HDTV/DTV takes over. See also PAL. |
| Natural language | This refers to a human language as opposed to a computer language. While computer languages such as C++ or Perl are very structured and are (arguably) designed to be clear in meaning to a parser, natural languages evolved over thousands of years and took on characteristics like accents, slang, inflection, local terminology, and meaning of words and phrases in context. The understanding and use of natural languages is a much harder problem for computers than understanding computer languages. |
| NBSP | An HTML command that is used to display a single text space without a visible character in that space. The format in HTML for this is and it can be used to position text or to fool a browser into behaving like text is in a space when there is no text visible. |
| NDIS | This spec was designed by Microsoft to allow multiple protocols to easily communicate with Network Interface Cards (NICs) without knowing anything about those cards. In theory you just have to install the NDIS driver for the particular NIC and you can bind multiple protocols to it. Previously you had to unload one protocol stack to load another. NDIS allows multiple stacks on the same card. |
| NDS | First introduced in the NetWare 4.0 network operating system, this is a system designed to make management of large networks easier for administrators. NDS allows users, groups, files, directories, and other local and remote resources to be displayed in a hierarchical tree structure. |
| Nerd | A term coined in the 1980s to describe intelligent but socially inept people. The term is often associated with Bill Gates. It has fallen out of favor somewhat, replaced by geek as a more up-to-date term for computer fanatics. |
| NetBEUI | A transport protocol developed by IBM in 1985 for small and medium networks. It is the underlying foundation of NetBIOS. NetBEUI today can be compared to IPX/SPX and TCP/IP. NetBEUI is efficient for small workgroups, but is not routable, and is a more broadcast-based protocol than IPX or TCP/IP, clogging the network with packets if you have more than 20 machines. It does not scale well. |
| NetBIOS Extended User Interface | A transport protocol developed by IBM in 1985 for small and medium networks. It is the underlying foundation of NetBIOS. NetBEUI today can be compared to IPX/SPX and TCP/IP. NetBEUI is efficient for small workgroups, but is not routable, and is a more broadcast-based protocol than IPX or TCP/IP, clogging the network with packets if you have more than 20 machines. It does not scale well. |
| NetWare | This is a network operating system developed by Novell. NetWare is a closed-source operating system that started life as a 16-bit OS, and moved to 32-bits with version 3. Management of NetWare was completely text-based until version 4, when remote GUI tools were added. NetWare initially used only the IPX/SPX networking protocol, and popularized the protocol. Version 4 added TCP/IP support by default. Legendary stories of NetWare's ability to run without need for restarting are circulated, much like the legendary tales of UNIX up-time. |
| Network | A group of interconnected computers. The computers must be capable of transferring data to form a true network--you can't just weld a bunch of computers together. Put that torch down! |
| Network Address Translation | A method that many ISPs use to extend their IP addressing to support more addresses than they own. The interior network uses one addressing scheme, and the exterior network uses the standard IPv4 Internet addressing. NAT devices can be routers, firewalls, or proxy-servers. To program a NAT device you must supply translation rules for how interior IP addresses are displayed to the outside world. You could, for example, set your firewall to act as if all traffic coming from inside your corporate network was coming from the firewall's IP address. |
| Network Attached Storage | The use of specialized devices that function simply as hard drives connected to a network. NAS devices typically consist of one or more hard drives in a housing that contains a simple operating system and a network connection. The use of NAS devices allows for cheaper and more easily expandable storage without requiring more complex and expensive multi-purpose servers to do the work of delivering files to network users. |
| Network Computer | A concept that came from the old days of dumb terminals and was a rehash of this idea promoted largely by Sun Microsystems. Network Computers were supposed to reduce the cost of standardized computers in the office environment but never really took off, as increasing application complexity demanded high-powered PCs. |
| Network Driver Interface Specification | This spec was designed by Microsoft to allow multiple protocols to easily communicate with Network Interface Cards (NICs) without knowing anything about those cards. In theory you just have to install the NDIS driver for the particular NIC and you can bind multiple protocols to it. Previously you had to unload one protocol stack to load another. NDIS allows multiple stacks on the same card. |
| Network File System | A type of distributed file system that allows NFS servers to give access to their local file system to NFS clients over a network using TCP/IP. The NFS standard was originally created by Sun Microsystems. |
| Network Interface Card | An add-in board that enables a computer to connect to some form of computer network. |
| Network News Transfer Protocol | The protocol that defines communications methods between news servers and news clients. NNTP communications use TCP port 119. The Usenet newsgroups are based on this protocol. |
| Network Operating System | An operating system designed to run across a network. It refers to the operating system that runs on a server, not the client. Network OSes are typically designed to provide access to server resources to clients, making the server function as a file server, print server, or other type of server. |
| Network Time Protocol | A protocol running over TCP/IP port 123 that is designed to synchronize clocks on servers. You can have NTP servers and NTP clients. Clients receive time data from the NTP server, and can adjust their clocks as necessary. Ideally the server is connected to some type of atomic clock that keeps regular time. |
| Newsgroups | Also referred to simply as "newsgroups," Usenet newsgroups are a huge bunch of Internet discussion groups that replicate across the Internet every so often. If you get a bunch of people together and request a group for yourself, you'll probably be able to create it. Topics range from technical discussions and debate to flame wars. However, the most infamous use of the newsgroups is the distribution of binary pictures and files as text. |
| NFC | Online speak for "No F'ing Clue" |
| NFS | A type of distributed file system that allows NFS servers to give access to their local file system to NFS clients over a network using TCP/IP. The NFS standard was originally created by Sun Microsystems. |
| Nibble | Four bits or half a byte. |
| NLX | A form factor similar to ATX. The difference is that NLX machines contain a riser card into which the other expansion cards are plugged. This allows for a shorter desktop case. NLX replaced LPX as a standard low profile form factor. |
| NNTP | The protocol that defines communications methods between news servers and news clients. NNTP communications use TCP port 119. The Usenet newsgroups are based on this protocol. |
| Node | One computer/machine or address on a network. If you managed a network with 10 printers, 50 servers, and 150 client machines, you could say you managed a network with 210 nodes. |
| Non-Breaking Space | An HTML command that is used to display a single text space without a visible character in that space. The format in HTML for this is and it can be used to position text or to fool a browser into behaving like text is in a space when there is no text visible. |
| Non-interlaced | A method of displaying images on a CRT monitor that are not interlaced. The scan lines occur one right after another, making for clearer and less jittery display of text. This method of display is overwhelmingly used today on CRT monitors. |
| Non-parity | This means without parity. Most often it is used to describe memory that does not have extra capacity available to check memory parity and report memory errors. See parity. |
| Non-parity Memory | This is DRAM that has no error-detecting ability. |
| Non-Uniform Memory Access | A multiprocessing architecture where each processor or small group of processors has its own group of memory chips. Accessing memory local to the processor is faster than accessing remote memory on other processor boards. NUMA typically scales better than SMP architectures, where memory is all accessed at the same speed in one large bank. |
| Non-Volatile RAM | A typically small amount of RAM that stores information even after you turn off your computer. It is used in modems for storing your settings and in hardware keys for protecting software. Flash memory is a type of non-volatile RAM. |
| Normal SCSI | A common misnomer for Narrow SCSI. The original form of SCSI, using 50 pins and transmitting data at 5MBps. See also Wide SCSI. Drives and adapters that support Narrow SCSI usually have an "N" in the part number. |
| Normalize | A verb used to describe what can be done to data to remove useless or extraneous entries. For example, if you set up a survey with choices A, B, and No Response, and then wanted to report the % of respondents that picked A or B, you could cut out the "No Responses" and thus normalize the data. Another example would be changing the loudness of an MP3 file by analyzing the file for the loudest part and then setting the loudness of the entire file to a percentage of that. That way, if you are putting together a mix file from many separate sources, you get a more uniform loudness. |
| Northbridge | The part of a chipset in a PC that controls communications among system memory, the processor, external cache, and the AGP bus. See also southbridge. You must pair a northbridge chip with a southbridge chip to make a usable chipset. |
| NOS | An operating system designed to run across a network. It refers to the operating system that runs on a server, not the client. Network OSes are typically designed to provide access to server resources to clients, making the server function as a file server, print server, or other type of server. |
| Notebook computer | A computer the size of a notebook. It is usually smaller and lighter than a laptop. |
| Novell Directory Services | First introduced in the NetWare 4.0 network operating system, this is a system designed to make management of large networks easier for administrators. NDS allows users, groups, files, directories, and other local and remote resources to be displayed in a hierarchical tree structure. |
| NP Complete | Generally this is a class of problems that are so difficult that even the best solutions cannot consistently determine their solutions in an efficient way. Specifically, NP Complete problems can only possibly be solved in polynomial time using a nondeterministic Turing machine (a computer capable of making guesses and checking them in polynomial time). Problems such as weather prediction, how to fill a box with odd-sized objects, and the Traveling Salesman problem fall into the realm of NP Complete problems. Because of the problem with finding the "best" solution, programs are often developed to find a usually reasonable solution. Take this into account the next time your weatherperson can't predict the weather--there are just too many variables. |
| NT File System | This alternative file allocation system available first with the Windows NT operating system, and then with Windows 2000. It allows for larger disk drives with smaller cluster sizes, as well as a performance increase and more robust security. NTFS is now the standard file system for Windows XP. |
| NTFS | This alternative file allocation system available first with the Windows NT operating system, and then with Windows 2000. It allows for larger disk drives with smaller cluster sizes, as well as a performance increase and more robust security. NTFS is now the standard file system for Windows XP. |
| NTP | A protocol running over TCP/IP port 123 that is designed to synchronize clocks on servers. You can have NTP servers and NTP clients. Clients receive time data from the NTP server, and can adjust their clocks as necessary. Ideally the server is connected to some type of atomic clock that keeps regular time. |
| NTSC | A group that is responsible for setting the standard for broadcast and reception of analog television signals in the United States and Japan. The original NTSC standards were set in 1953, and call for 525 horizontal lines of resolution, interlaced scanning, and a 60Hz refresh rate. That standard continues to exist until HDTV/DTV takes over. See also PAL. |
| Null modem | There really is no "null modem" per se, but usually a null modem cable. This is a cable that connects two computers together via serial ports and allows them to communicate. Some hardware manufacturers of network hardware, such as hubs and routers, include serial ports for programming their devices--you use a null modem cable to communicate with these devices. It's basically a modem cable with a couple of connections reversed. |
| NUMA | A multiprocessing architecture where each processor or small group of processors has its own group of memory chips. Accessing memory local to the processor is faster than accessing remote memory on other processor boards. NUMA typically scales better than SMP architectures, where memory is all accessed at the same speed in one large bank. |
| NVRAM | A typically small amount of RAM that stores information even after you turn off your computer. It is used in modems for storing your settings and in hardware keys for protecting software. Flash memory is a type of non-volatile RAM. |
| Object | This can refer to the objects in object-oriented programming or the objects in OLE (Object Linking and Embedding). In OLE an object is a piece of a document, a graphic, or some multimedia. In object-oriented programming an object can be a spell checker or a piece of a graphics program used to draw squares or circles. Do you remember the crazy story people used to try to tell about a word processor where you could pick all of your favorite pieces (favorite spell checker, grammar checker, text editor, font manager, etc.) and piece them together to form the ultimate customizable word processor? Well, those pieces are objects. |
| Object Linking and Embedding | A standard for sharing data between applications. It has been around since Windows 3.1 and continues to improve. For example, if you cut a picture out of Paint and paste it into a word processor document, you are using OLE to properly put the data into your document. Of course, if it doesn't work quite right you can blame OLE, or the program's use of it. OLE allows objects to be linked to and embedded in other documents. Linking creates a link to the actual object; embedding puts a copy of the object into the document. You can usually access the program an object was created with in order to edit the linked or embedded object just by clicking on the object. This is much more advanced than just taking a screenshot of the data you want and pasting it into another program as a graphic that has no relation to the original data. |
| Object-oriented Programming | This term refers to programming languages that allow you to work with objects. These objects can contain not only data type and data structure information, but also information about how the object can be used by procedures. |
| Object-oriented technology | Technology--usually programming languages--designed to work with objects. |
| OC-12 | A fiber optic connection that can handle 622Mbps, often used for the 622Mbps ATM protocol. |
| OC-192 | A fiber optic connection that can handle 10Gbps connection speeds. |
| OC-24 | A fiber optic connection that can handle 1.244Gbps connection speeds. |
| OC-255 | A fiber optic connection that can handle 13.21Gbps connection speeds. |
| OC-3 | A fiber optic connection that can handle 155Mbps, often used for the 155Mbps ATM protocol. |
| OC-48 | A fiber optic connection that can handle 2.488Gbps connection speeds. |
| OC-96 | A fiber optic connection that can handle 4.976Gbps connection speeds. |
| OCR | The technology that allows computers to "read" the text from physical objects. It requires a graphical representation of text to interpret. This usually comes from a scanned image. |
| Octet | A group of eight bits, also called a byte. |
| ODBC | A standard API for communicating with database servers. There are different ODBC drivers supporting most of the major database servers, such as Oracle and Microsoft SQL Server. If you program to ODBC you get the advantage of (theoretically) being able to easily use your application on different databases without reprogramming. However, ODBC drivers are not always perfect. |
| ODI | A protocol-independent structure used by early Novell NetWare clients. It provides support for simultaneous connection to multiple network protocols, much like Microsoft's NDIS did back in the 16-bit client days. |
| OEL | A type of display technology that allows for flat screens that are very bright and offer wider viewing angles than LCD technology. As well, no backlight is required. OEL technology may one day replace LCD technology. See OLED for a similar, competing technology. |
| OEM | This acronym is used to denote equipment that is sold to other companies or resellers for integration into systems. For example, a hard drive manufacturer may sell an OEM hard drive in bulk quantities with no manual or cables with the promise that it will go into full systems--or maybe external enclosures--and be resold. What often happens is that you can pick up OEM products at computer shows for low prices. Large computer companies use OEM monitors with their brand name on them instead of actually building their own monitors. |
| Office Suite | The set of software products that are required by an office, most often comprised of a spreadsheet program, a word processor, a scheduler, and a presentation manager. Sometimes the suites will include a financial package and a database program as well. These are put together by a single company, so they are made to work with one another. |
| Offline | Being away from your computer or the Internet, or your computer being off and disconnected from the Internet. If you were a character in the movie Tron, you died when you went offline. |
| Ogg Vorbis | An audio codec designed to compete with the MP3 codec. One of the main goals of Ogg Vorbis was to provide an audio encoding scheme that was free from corporate copyrights and licensing fees, such as the ones MP3 websites and hardware makers must pay to companies that own part of the encoding technology built into the MP3 format. Like MP3s, Ogg Vorbis supports fixed and variable bit rates. |
| OLAP | A group of technologies and applications that collect, manage, process, and present multidimensional data for analysis and management purposes. To be effective, results of the analysis done must be presented quickly, and within the same application or a closely linked application. |
| OLE | A standard for sharing data between applications. It has been around since Windows 3.1 and continues to improve. For example, if you cut a picture out of Paint and paste it into a word processor document, you are using OLE to properly put the data into your document. Of course, if it doesn't work quite right you can blame OLE, or the program's use of it. OLE allows objects to be linked to and embedded in other documents. Linking creates a link to the actual object; embedding puts a copy of the object into the document. You can usually access the program an object was created with in order to edit the linked or embedded object just by clicking on the object. This is much more advanced than just taking a screenshot of the data you want and pasting it into another program as a graphic that has no relation to the original data. |
| OLED | A flat panel display technology that requires no backlight and could someday be simpler to construct than LCD screens. Check out OEL technology as well. |
| OLTP | A group of programs that allow real-time inputting, recording, and retrieval of data to/from a networked system. The speed of recording the data is critical, as is the reaction time of the system, so that people entering data are not bogged down. |
| On-chip | This term is most often used when referring to the L2 cache on a microprocessor. It implies that the L2 cache itself is on the same single piece of silicon as the microprocessor. |
| On-die | This term is most often used when referring to the L2 cache on a microprocessor. It implies that the L2 cache itself is on the same single piece of silicon as the microprocessor. |
| Online | This term refers to anything that's on the Internet, as in "I've got this great online resource for you to check out at www.geek.com." |
| OnLine Analytical Processing | A group of technologies and applications that collect, manage, process, and present multidimensional data for analysis and management purposes. To be effective, results of the analysis done must be presented quickly, and within the same application or a closely linked application. |
| OnLine Transaction Processing | A group of programs that allow real-time inputting, recording, and retrieval of data to/from a networked system. The speed of recording the data is critical, as is the reaction time of the system, so that people entering data are not bogged down. |
| Open Data-link Interface | A protocol-independent structure used by early Novell NetWare clients. It provides support for simultaneous connection to multiple network protocols, much like Microsoft's NDIS did back in the 16-bit client days. |
| Open Database Connectivity | A standard API for communicating with database servers. There are different ODBC drivers supporting most of the major database servers, such as Oracle and Microsoft SQL Server. If you program to ODBC you get the advantage of (theoretically) being able to easily use your application on different databases without reprogramming. However, ODBC drivers are not always perfect. |
| Open Source | Software that can be freely distributed, and must be distributed along with its source code. Thus the source can be changed easily, and the program can be altered to fix bugs or add features. Depending on the Open Source license (see FreeBSD license and GNU Public License), you may be unable to redistribute altered code or charge money for the distribution of the software. Some popular examples of Open Source software are Linux and Mozilla. |
| OpenGL | A 3D graphics language developed by Silicon Graphics. OpenGL support is built into Windows NT. You can see some examples by checking out the NT screensavers. Some 3D graphics accelerators have OpenGL acceleration built-in. When Windows 2000 was released, Microsoft started to use DirectX to speed up 3D operations instead of OpenGL. Some games today use OpenGL, and some use DirectX. |
| OpenVMS | This is synonymous with VMS. It is an operating system designed by Digital Equipment Corp. to run on its VAX hardware. It was initially called VMS, but renamed OpenVMS when it was ported to run on the 64-bit Alpha processor, and also to signify its support of POSIX. |
| Operating System | The program that allows you to access the basic functions of your computer. It is the minimum software required to run a program. Thus, you must have an operating system installed and then the programs run on top of it--unless you have a program with an entire operating system embedded into it, which is possible. |
| Optical Carrier Level 12 | A fiber optic connection that can handle 622Mbps, often used for the 622Mbps ATM protocol. |
| Optical Carrier Level 192 | A fiber optic connection that can handle 10Gbps connection speeds. |
| Optical Carrier Level 24 | A fiber optic connection that can handle 1.244Gbps connection speeds. |
| Optical Carrier Level 255 | A fiber optic connection that can handle 13.21Gbps connection speeds. |
| Optical Carrier Level 3 | A fiber optic connection that can handle 155Mbps, often used for the 155Mbps ATM protocol. |
| Optical Carrier Level 48 | A fiber optic connection that can handle 2.488Gbps connection speeds. |
| Optical Carrier Level 96 | A fiber optic connection that can handle 4.976Gbps connection speeds. |
| Optical Character Recognition | The technology that allows computers to "read" the text from physical objects. It requires a graphical representation of text to interpret. This usually comes from a scanned image. |
| Optical Disk | A plastic disk that can store information in a method so that it can be read by a laser. The laser is shot at the disk and, based on its reflection, the value of data is calculated. |
| Optical Drive | A storage device that uses light to store data instead of magnetism. To write, it uses a laser to change a tiny portion of an optical disk so that it can be read later by checking the state of that portion. |
| Ordered Tree | A tree where the children of each node have a designated order (not necessarily based on their value) and can be referred to specifically. |
| Organic Electroluminescent | A type of display technology that allows for flat screens that are very bright and offer wider viewing angles than LCD technology. As well, no backlight is required. OEL technology may one day replace LCD technology. See OLED for a similar, competing technology. |
| Organic LED | A flat panel display technology that requires no backlight and could someday be simpler to construct than LCD screens. Check out OEL technology as well. |
| Orthogonal | This term is used to describe two or more things that are independent of one another. Also, it is a mathematical term that refers to vectors that meet at right angles. |
| OS/2 | An operating system originally developed by Microsoft and IBM; Microsoft dropped out of the project to concentrate on its Windows operating systems. IBM continued to develop OS/2, and to this day there are still OS/2 users out there, mainly in the financial and banking world. OS/2 is a full 32-bit operating system. |
| OSI Model | A way of representing the complexities of computer networking in a 7-layer model, ranging from the physical hardware of networking all the way up to how application programs talk to the network. The 7 layers are: physical, data link, network, transport, session, presentation, and application. The 7-layer OSI model can be used to help diagnose network problems. It is also used as a measurement of how well people know their networking. If you're looking for a job in networking, you should familiarize yourself with the OSI model. |
| Output | Anything that comes out of a computer or system, either electronically or physically, as in, "Watch out for that pile of OUTPUT." |
| Overburning | The process of recording more than 74 minutes of audio or more than 650 MB of data onto a CD-R disk. There are software programs that allow you to do this, and now there is media that supports larger storage than the standard CD-R normally holds. |
| Overclocking | The act of running a chip at a higher clock speed than it was specified for. Very often, chips are capable of running faster than they are specified for, and thus can be safely overclocked. You overclock a chip by setting it at a higher bus speed, a higher multiplier, or both. Sometimes you need to set the chip to run at a higher voltage to accomplish this, further increasing the heat output of the chip. |
| Overdrive | A processor upgrade sold by Intel that is used to upgrade an older processor to a newer, faster processor. |
| Overflow | This is when there is more information than can be properly handled. It is often used to describe the production of a number larger than a variable can handle. For instance, if you are expecting 10 digits but receive 11, that's overflow. |
| P2P | A method of distributing files over a network. Using P2P client software a client can advertise, send, or receive files with another client. Some P2P file distribution systems require a centralized database of available files (such as Napster), while other distribution systems (like Gnutella) are more decentralized. |
| P54C | The official part number for the Pentium processor from Intel. |
| P55C | The official part number for the Pentium processor with MMX technology from Intel. |
| Packet Filter | Anything that filters out network traffic based on a sender's address, receiver's address, and the type of protocol being sent. Some routers support packet filtering, all firewalls do, and some proxy servers do as well. |
| Packet InterNet Gopher | Part of the standard TCP/IP suite of protocols that allows you to check your connectivity with other devices, or to check whether your own TCP/IP stack is working properly. Normally you type in something like "ping 10.250.250.37" or "ping www.geek.com," and you either get a response from that IP address or not. PING is extremely useful for debugging network problems. |
| Page | Some regular amount of memory that is accessed by a program or hardware. Memory is split into pages to be dealt with more easily. For example, a database program may deal with 2 KB pages of memory. If it needs 2.1 KB of space to store some data, it will use two pages, or 4 KB of data, since you can't split pages up into smaller groupings of memory. |
| Page Fault | This is not an error, as "fault" would usually indicate. It simply means that the computer had to resort to using the swap file as memory. If you are getting a lot of page faults you should upgrade your system's memory. |
| Pages Per Minute | This term usually refers to the amount of printed pages a printer can output over a minute's time. The time is based on some average amount of ink or toner coverage on a page. If you are printing complex graphics on inkjet color printers, expect your printer to function more slowly than its PPM rating, as it has to make up to four passes over each area of a page instead of a single pass for black ink only. |
| Paging | The act of moving pages of memory from RAM to virtual memory on a hard drive. Excessive paging is caused by a lack of actual system memory. In this case the system has to use the hard drive as memory frequently, and performance is degraded. |
| PAL | The mainly European standard of displaying analog television signals. It consists of 625 horizontal lines of resolution at 50Hz. See also NTSC. |
| Palm Query Application | A small applet that can be downloaded onto a Palm OS-based PDA that allows for the retrieval of information from the Web. PQAs are intended to minimize the flow of information over a slow wireless connection. |
| Palmtop | A form factor of a computer that can easily fit in your palm. This usually refers to very small PDAs with no keyboards, but can also refer to larger fold-open PDAs, or micro-laptops with full keyboards. |
| Pantone | A standard set of colors, with each color specified by a number. The Pantone colors can be further broken down into a color separation used by professional printers to calibrate color reproduction. |
| Parallel | This means in unison, or many things at the same time. It most commonly refers to a computer with multiple processors that can all function independently at the same time. It also refers to cabling or connection standards that use several wires to transmit data. See also serial. |
| Parallel Port | The parallel port is found on just about all PCs. It's a 25-pin interface cable (also called DB-25) that is designed for connection to a printer. Normally the parallel port takes up IRQ 7. In addition to printers, you can connect many other devices, such as scanners and storage. Of course, the parallel port is slow; it can transfer data at a maximum speed of 512Kbps, or 24 times slower than USB 1.x. |
| Parity | The use of an extra bit on memory chips that serves as a checksum, and can let the operating system know if single-bit memory errors are occurring. |
| Parity Memory | Memory that contains a summary of its stored information. The parity does not exactly have a copy of the original, but just enough information to verify the integrity of the original. |
| Parse | The act of separating data into more easily understood chunks. |
| Parser | Strictly speaking, this is something that separates data into more easily understood chunks. More practically, a parser is the part of a compiler that goes through a program and cuts it into identifiable chunks before translation. Assuming that a parser is written reliably, if the parser cannot parse a program then the program contains syntax errors. |
| Partially ordered tree | A binary tree where each node of the tree is less than or equal to each of its children nodes. |
| Partition | A section of a hard drive. You must create at least one partition to begin using a new hard drive, and you can create multiple partitions and keep chunks of your data separate. It is also possible to install multiple OSes on these multiple partitions. Usually it's just one OS per partition, but some OSes, like Windows 95/98/Me and Windows NT/2000/XP, for example, are designed to run together in the same partition as long as you use a compatible file system to format the partition. |
| Partitioning | The act of breaking a hard drive up into one or more pieces, or "partitions." |
| Pascal | A programming language that was designed to teach computer science students the concepts of programming. It's almost like C for dummies. In fact, the two languages are very similar, but the stoic brackets of C are changed to happy and fluffy "Begin" and "End" statements. Also, many of the more complex functions of C are missing, but Pascal is still a fully functional language. Borland used Pascal as the basis for its Delphi programming language. |
| Passive Matrix | LCD panels that are passive matrix have a duller, dimmer image than those with active matrix screens. Visibility and clarity decrease at smaller angles off of central viewing than with active matrix screens as well. Passive matrix LCD screens are no longer being produced by LCD manufacturers. |
| Patch | Minor updates to programs that are distributed with only the changes and not the whole program. Imagine an instruction manual that has an extra page stapled in it with a correction of some text for that page. That is what would be considered a patch. |
| Patch cable | The common name for any network cable that is used to connect, or "patch," any two network ports. |
| Patch panel | A group of network ports stuck together for easy accessibility. Usually this panel resides in a wiring closet or server room. Connections are made between this panel and ports on a hub to enable a network connection at a remote port. Each port on the patch panel is connected by a longer cable (often run through the ceiling) to a remote port anywhere in an office that needs a computer hooked up to the network. |
| Path | The group of directories that are searched every time a command is entered in a command line if that command is not found in the current working directory. In most text-based environments you can specify additional directories to be added to the path to make your command line contain additional directories. |
| Payload | The eventual action taken by a virus once it has installed itself on a system. This action may be immediate, or it could wait for some trigger in the future, such as a specific date or a certain amount of time, to take action. The possible actions of a virus are limited to your imagination, although some payloads include deletion of files, formatting hard drives, or simply displaying a message to the user. |
| PBX | A private phone switch used within a company that allows inter-company phone calls without using outside lines. It also connects to one or more outside POTS lines, which are often partitioned off into outgoing lines, incoming lines, or lines that can be used for both purposes. PBXs today use digital connections for inter-company calls, thus you must use digital phones as opposed to standard analog phones (and modems). A PBX is typically a large and costly piece of machinery maintained and/or supported by the company that sold the PBX. There are various options that can be added onto PBXs for call reporting, call management, and voicemail. |
| PC Card | A newer synonym for PCMCIA Card. |
| PC100 | The standard that SDRAM makers adhere to to be sure that SDRAM running at 100MHz works properly. PC100 SDRAM normally works fine in 66MHz SDRAM motherboards. |
| PC100 SDRAM | The standard that SDRAM makers adhere to to be sure that SDRAM running at 100MHz works properly. PC100 SDRAM normally works fine in 66MHz SDRAM motherboards. |
| PC1066 RDRAM | Rambus RDRAM that runs at a speed of 533MHz double-pumped to an effective speed of 1.06GHz. Memory throughput in systems featuring this type of DRAM is 2.1GB/second per 16-bit channel, or 4.2GB/second per 32-bit channel. |
| PC133 | A type of SDRAM that is designed to be run at 133MHz operation. It is pin-compatible with PC100 SDRAM and 66MHz SDRAM, and comes in a DIMM form factor. |
| PC133 SDRAM | A type of SDRAM that is designed to be run at 133MHz operation. It is pin-compatible with PC100 SDRAM and 66MHz SDRAM, and comes in a DIMM form factor. |
| PC1600 | DDR SDRAM running at 100MHz double-pumped to an effective speed of 200MHz. It has a maximum data transfer rate of 1.6GB/second for one PC1600 channel. |
| PC200 DDR SDRAM | The DDR memory chips used to assemble PC1600 DDR memory modules. |
| PC2100 DDR SDRAM | A type of DDR SDRAM running at 133MHz double-pumped to an effective speed of 266MHz. It is referred to as PC2100 because systems featuring DDR SDRAM at 266MHz have a maximum data transfer rate of 2.1GB/second. |
| PC266 DDR SDRAM | The DDR memory chips used to assemble PC2100 DDR memory modules. |
| PC2700 | A type of DDR SDRAM running at 166MHz double-pumped to an effective speed of 333MHz. It is referred to as PC2600 because of its maximum data transfer rate of 2.7GB/second. |
| PC3200 | A type of DDR SDRAM running at 200MHz double-pumped to an effective speed of 400MHz. It is referred to as PC3200 because of its maximum data transfer rate of 3.2GB/second in a single 64-bit channel. |
| PC333 DDR SDRAM | The DDR memory chips used to assemble PC2700 DDR memory modules. |
| PC400 DDR SDRAM | The DDR memory chips used to assemble PC3200 DDR memory modules. |
| PC600 RDRAM | Rambus RDRAM that runs at a speed of 266MHz double-pumped to an effective speed of 532MHz. Memory throughput in systems featuring this type of DRAM is about 1.06GB/second. |
| PC700 RDRAM | Rambus RDRAM that runs at a speed of 356MHz double-pumped to an effective speed of 712MHz. Memory throughput in systems featuring this type of DRAM is about 1.42GB/second. |
| PC800 RDRAM | Rambus RDRAM that runs at a speed of 400MHz double-pumped to an effective speed of 800MHz. Memory throughput in systems featuring this type of DRAM is 1.6GB/second. |
| PCB | The normally green plastic board that is imprinted with one or more layers of circuitry. Examples of common PCBs include motherboards, PCI cards, and AGP cards. The boards can hold microchips and other components, and are a way to link such components together. |
| PCI | This interface was designed to supplant the VL-Bus architecture and provide a standard slot with a reduced size for high-speed peripherals. It normally runs at 33MHz on a 32-bit bus in a PC, but the specification allows for 64-bit and 66MHz operation that provides up to 532 MB of data transfer per second. |
| PCI-X | An extension to the PCI interface developed by IBM, HP, and Compaq. The extension allows data to be transferred at 1 GB per second using a 64-bit bus running at 133MHz. PCI-X peripherals are fully compatible with PCI and vice-versa, but will not run faster than the chipset or peripheral allows. |
| PCL | A set of commands used to communicate with Hewlett Packard printers. Each printer company has its own language, but PCL has become a generic term to describe these languages. See also Postscript. |
| PCMCIA | Aside from winning the award for being the longest and most-annoying-to-pronounce technology acronym, PCMCIA is a credit card-sized interface card standard. PCMCIA cards are most commonly found in notebook computers. You'll usually find two slots on newer models--two small slots can hold two Type I or II cards or one Type III card. Type III cards are usually mini hard drives; Type I or II cards are usually modems or network cards, but can also be sound cards, SCSI adapters, and any other interface you can imagine. It is possible to use PCMCIA cards on a desktop computer, but you need to purchase special hardware that's not usually worth it--unless you've got some really special use for your cards, such as secure authentication using a PCMCIA card. |
| PDA | PDAs are basically beefed-up organizers or toned-down laptops. They have small LCD screens, some form of pen or keyboard input, and software for organization, OCR, and contact management. Some have even more features, such as Web browsing or Internet e-mail. Most PDAs are designed to fit in one hand while you use the other hand for input. |
| PDC | In Windows NT and 2000 networking, this machine is the main machine that responds to security authentication requests, such as logging in, within its domain. The PDC may be backed by one or more backup domain controllers that can also handle security authentication. |
| Peer to Peer | A method of distributing files over a network. Using P2P client software a client can advertise, send, or receive files with another client. Some P2P file distribution systems require a centralized database of available files (such as Napster), while other distribution systems (like Gnutella) are more decentralized. |
| Peering Relationship | An agreement where one ISP agrees to exchange some level of traffic with another ISP. Sometimes, based on the level of traffic mismatch, one ISP pays the other ISP. |
| Peltier Junction | When electrical current is applied to a thermocouple a temperature difference is created, with one side of the thermocouple being hotter than room temperature and the other being cooler. Peltier Junctions (Peltiers for short) can be used to cool microprocessors, where the cool side contacts the microprocessor and the hot side contacts a heatsink. Peltier Junctions are rated in watts. If you do not use the appropriate wattage a Peltier Junction will be ineffective. |
| Performance Rating | A measure of processing power. The term was coined by Cyrix to compare its 6x86 processor to Intel's Pentium processor that ran at faster processor speeds. The 6x86 was a more complex chip that could perform as well as Pentium chips at faster clock speeds in some operations. Cyrix continued to use its Performance Rating on future chips until it was bought out by Via. AMD more recently used PR Ratings that were more accepted by the industry for rating its Athlon XP/64 and Opteron chips. |
| Peripheral | Any device that is not part of the motherboard, aside from memory and the CPU. For example, video cards, sound cards, modems, and hard drives are peripherals. When speaking about the exterior of a PC peripheral refers to anything that can be connected to the exterior of a PC, like an LCD monitor or FireWire hard drive. |
| Peripheral Component Interconnect | This interface was designed to supplant the VL-Bus architecture and provide a standard slot with a reduced size for high-speed peripherals. It normally runs at 33MHz on a 32-bit bus in a PC, but the specification allows for 64-bit and 66MHz operation that provides up to 532 MB of data transfer per second. |
| Peripheral Component Interconnect Extended | An extension to the PCI interface developed by IBM, HP, and Compaq. The extension allows data to be transferred at 1 GB per second using a 64-bit bus running at 133MHz. PCI-X peripherals are fully compatible with PCI and vice-versa, but will not run faster than the chipset or peripheral allows. |
| PERL | Created by system admin Larry Wall in the mid 1980s, this programming language was originally intended to fill a gap and help out with administration tasks. From those meager beginnings PERL has become a programming language often associated with the Web and UNIX. PERL is the most common programming language used to program CGI scripts. It is a very powerful language that can be used to easily modify large amounts of text files with hardly any programming required. PERL aficionados use it for doing everything. |
| Permanent Virtual Circuit | A path through a network from one fixed point to another that appears to be a dedicated circuit; however, the path can be changed and rerouted if necessary. The PVC typically travels over routers and connections that are used by other traffic, but appears to be private for all intents and purposes. Also, packets are sent and arrive in order, and do not need to be resequenced. |
| Personal Computer | This is slang for IBM Personal Computer, or IBM-PC. This is the class of computers the works (so far) on the x86 instruction set, and were first developed by IBM as a means to put a computer in your home. Before that IBM computers were only used in business. After the PC was developed, many clone PC makers began developing them as well, and that has led to the large amount of components that are PC-compatible; but it has also caused some problems when cheap components try to work properly with one another. |
| Personal Computer Memory Card International Association | Aside from winning the award for being the longest and most-annoying-to-pronounce technology acronym, PCMCIA is a credit card-sized interface card standard. PCMCIA cards are most commonly found in notebook computers. You'll usually find two slots on newer models--two small slots can hold two Type I or II cards or one Type III card. Type III cards are usually mini hard drives; Type I or II cards are usually modems or network cards, but can also be sound cards, SCSI adapters, and any other interface you can imagine. It is possible to use PCMCIA cards on a desktop computer, but you need to purchase special hardware that's not usually worth it--unless you've got some really special use for your cards, such as secure authentication using a PCMCIA card. |
| Personal Digital Assistant | PDAs are basically beefed-up organizers or toned-down laptops. They have small LCD screens, some form of pen or keyboard input, and software for organization, OCR, and contact management. Some have even more features, such as Web browsing or Internet e-mail. Most PDAs are designed to fit in one hand while you use the other hand for input. |
| Personal Information Manager | A program into which you can enter your personal information, such as your schedule and important contacts. Often PIMs run on PDAs, and allow for synchronization between the PDA and a desktop computer running the same program. |
| Perspective Correction | This correctly alters the textures in a scene to give a sense that all the images on the screen converge on one central point way out in the distance. It's why things far away look smaller in 3D games. |
| Petabyte | This is 2^50 bytes. One thousand terabytes/one million gigabytes/one billion megabytes/one trillion kilobytes/one quadrillion bytes (approximately). |
| Petaflop | This is the ability of a computer to do one quadrillion floating point operations in a second. See also teraflop, gigaflop, and megaflop. |
| PGA | A form of chip with a group of pins in concentric rectangles, designed to fit into a PGA slot. x86-compatible chips that fit into socket 7, socket 370, and Super 7 are designed in this format, as are newer sockets such as AMD's Socket A and Intel's Socket 423 and 478 for its Pentium 4 chips. |
| PGA slot | This slot accepts a PGA chip. A form of chip with a group of pins in concentric rectangles, designed to fit into a PGA slot. x86-compatible chips that fit into socket 7, socket 370, and Super 7 are designed in this format, as are newer sockets such as AMD's Socket A and Intel's Socket 423 and 478 for its Pentium 4 chips. |
| Phase Alternation Line | The mainly European standard of displaying analog television signals. It consists of 625 horizontal lines of resolution at 50Hz. See also NTSC. |
| Phone Switch | These are generally large cabinets with groups of phone port cards plugged into them. On one end the cards connect to the phone company via T1 or larger line; on the other end they usually connect to a punch-down block on the wall, which is in turn connected to groups of ports at people's desks. Thus, people can plug phones into these ports and be connected to the phone company. The phone switch manages the connections between you and the outside world. Many offices have their own dedicated switches that they can maintain and control (within certain guidelines). In residential areas the phone company controls the switches. |
| PHP | Created in 1994, this is a versatile embedded scripting language that can be placed into HTML documents. As long as the webserver supports it, PHP can be used to generate HTML pages by accessing a database. PHP code is executed on the server, and offers an alternative to CGI or SSI calls, or the use of languages such as ColdFusion. |
| Phreak | A person who breaks into phone systems, generally to get free phone or voicemail service--thus the "ph" at the beginning of the term, similar to "phone." It can be expanded to apply to anyone who breaks into systems to get free goods or services. |
| Picosecond | 1/1000 of a nanosecond, or one trillionth of a second. The individual transistors and logic gates on modern microchips flip in lengths of time measured in picoseconds. |
| PIM | A program into which you can enter your personal information, such as your schedule and important contacts. Often PIMs run on PDAs, and allow for synchronization between the PDA and a desktop computer running the same program. |
| Pin | An exposed and rigid metal wire. A group of pins make up a "male" connector, and you can plug it into a compatible female connector. On motherboards and add-on cards you can often connect pins electrically with a jumper to change features on the boards. Pins are also found on cables with male connectors. |
| Pin Grid Array | A form of chip with a group of pins in concentric rectangles, designed to fit into a PGA slot. x86-compatible chips that fit into socket 7, socket 370, and Super 7 are designed in this format, as are newer sockets such as AMD's Socket A and Intel's Socket 423 and 478 for its Pentium 4 chips. |
| Pincushioning | One form of image distortion on a monitor--good monitors have controls to deal with this problem. Basically, the top and bottom of the screen are wider than the middle (convex) or vice versa (concave). When corrected properly, the left and right side of the monitor screen are straight vertical lines. |
| PIO | Input/Output standards on IDE hard disk drives. If you have a hard drive that supports one PIO mode, you need your interface to support it as well for maximum performance. The data transfer rates for the various PIO modes are: PIO mode 0 - 3.3Mbps; PIO mode 1 - 5.2Mbps; PIO mode 2 - 8.3Mbps; PIO mode 3 - 11.1Mbps; PIO mode 4 - 16.6Mbps. Ultra IDE doubles the data transfer rate of PIO mode 4. |
| Pipeburst Cache | A form of L2 cache that uses pipelining to speed data access by being able to feed data to the CPU at the same time as it pulls data from memory. The burst mode also allows the cache to fetch additional data from main memory before the CPU requests it. This type of cache was used back in the Pentium days when L2 cache was separate from the processor. Pipeburst caches is an abbreviation, or bastardization, for Pipeline Burst Cache, just like "ain't" is an abbreviation for "am not." |
| Pipeline | The technique of processing multiple parts of an instruction at the same time. Many processors have two or more instruction pipelines--think of them as automobile assembly lines. As one instruction is executed, the next instruction is being decoded, and the one after that is being fetched from memory (i.e., Ellen welds the frame of one car, while Frank paints another one, and Jimmy puts the tires onto the finished frame of another car). The pipeline is only as fast as its slowest member (i.e., if it takes Jimmy an hour to put on some tires then it doesn't matter that Ellen can weld the frame in 20 minutes; either the line will slow down, or you need three Jimmys for optimal performance). The speed-up you get from having a pipeline is about equal to the amount of pieces of pipe, though it's slightly slower due to the fact that the first instruction executed begins to fill the empty pipeline (i.e., Jimmy can't put on any tires if Ellen is still welding the frame of the first car through the line!). If something happens that empties the pipeline then performance suffers--the penalty is greater with larger pipelines. For some practical examples, the original PowerPC G4 has a 7-stage pipeline, while the Pentium 4 has a 20-stage pipeline. Processors with smaller pipelines are typically seen as more efficient, but at higher speeds the short pipeline can be limiting. |
| Pipeline Burst Cache | A form of L2 cache that uses pipelining to speed data access by being able to feed data to the CPU at the same time as it pulls data from memory. The burst mode also allows the cache to fetch additional data from main memory before the CPU requests it. This type of cache was used back in the Pentium days when L2 cache was separate from the processor. |
| PKI | The infrastructure needed to support public key encryption. It requires a certificate authority to issue and verify the public keys, a registration authority that verifies the identity of a person or organization before a key is issued, a certificate directory of the public keys, and a certificate management system. Public key encryption can be used to verify an identity or to encrypt data or messages. |
| Plain Old Telephone Service | The regular telephone service that people have in their homes. Newer technologies such as ISDN, digital phones, cellular phones, or DSL are not referred to as POTS. |
| Plastic Pin Grid Array | The PPGA form factor, also referred to as socket 370, was created by Intel to offer a lower cost alternative to its Slot 1 packaging. It exemplified the first big move back to sockets after L2 caches were embedded in the processor die and cartridges with the chip and separate L2 cache were no longer needed. |
| Platform | A means of generically grouping like computers. Macintosh computers are a platform; so are PCs running Windows. It's not very specific, and multi-platform support can mean many things. If someone says to you "this application supports multiple platforms," ask that person which ones he or she is talking about. |
| Platter | One of the rigid disks inside a hard drive used to store information. Hard drives typically contain between one and 5 platters apiece, but can contain more. Platters have been historically made out of aluminum, and more recently glass. |
| PLD | An integrated circuit that consists of an array of AND and OR gates whose operation can be modified. The programming of the devices is done by blowing fuses on the PLD. |
| Plenum Cable | This type of cabling is meant to be used with a plenum ventilation system. It is used in situations where the smoke from fire would saturate the building through air ducts. Specifically, plenum cable should not produce lethal fumes when burned. Plenum cable is more expensive than cable made from PVC shielding; however, PVC cable can be used in buildings with newer ventilation systems designed to move burning fumes away from breathing space. Check your local building codes, local fire marshal, or office management company to find out which type of cable to install. |
| Plug and Play | A standard that was supposed to make adding peripherals to your system as easy as plugging them in and using them. Also referred to as Plug-and-Pray, its biggest contribution, aside from the endless cycle where Windows keeps finding and installing drivers you don't want installed, is the removal of jumpers from many devices. Seriously, though, Plug-and-Play has actually made configuration easier, even if it took a while to get there. |
| PNG | PNG is an image format that uses lossless compression, similar to the GIF format. How the PNG format differs, however, is that the GIF format involves licensing the LZH compression standard from Unisys, whereas PNG is a public domain format that was designed to replace GIFs. Support for PNG is currently included in the current versions of almost all modern browsers. |
| PNP | A standard that was supposed to make adding peripherals to your system as easy as plugging them in and using them. Also referred to as Plug-and-Pray, its biggest contribution, aside from the endless cycle where Windows keeps finding and installing drivers you don't want installed, is the removal of jumpers from many devices. Seriously, though, Plug-and-Play has actually made configuration easier, even if it took a while to get there. |
| Point Of Presence | A local telephone number through which you can access your ISP. The largest national ISPs have POPs all over the country. |
| Point to Point | A type of network communication where information is sent from a single source to a single destination, eliminating any extraneous data transmission. See also broadcast. |
| Point to Point Protocol | The mode of transport used to connect a computer to the Internet via a dial-up adapter (a modem). |
| Point to Point Tunneling Protocol | A remote access protocol that allows people to make a connection to easily connect to their local network through the Internet or some other large network. Conversations are kept private through encryption. See also Virtual Private Network. |
| Pointer | (1) In programming, think of a pointer as an address. The address can point to just about anything, including another pointer. Ultimately, if you follow the trail of pointers you'll probably find some data--pointers are most often used to point to data. The purpose of pointers is so that when you are programming you can pass around a small address that points to some data, instead of passing the actual data around. (2) Pointers can also refer to the icon on the screen that you move around with a mouse or other pointing device. In a GUI environment you need a pointer to point to things so that you can select them. |
| Poll | When one computer, device, or program asks for an answer to a query from another computer or device over a period of time until a condition is met. For example, a program may poll an IP address to see when it is available. |
| Polyvinyl Chloride | The common vinyl shielding used to cover the pairs in the copper four-pair wire used for numerous Ethernet standards. When burned it gives off deadly fumes, so plenum wire must be used in certain office buildings instead of PVC. |
| POP3 | A standard for client/server transmission of e-mail. An e-mail server holds the e-mail, and you use a POP3 client to fetch the mail from a server. IMAP is a newer e-mail client/server protocol with more options. |
| Port | To port something you translate the code for a program from one platform to another. You could port a program you wrote on a PC over to a Macintosh, for example. Port |
| Port Replicator | A device that is used to provide laptops--with limited ports and expansion options built-in--with a larger amount of ports and expandability. Most port replicators are proprietary devices that work with one particular model of laptop and add extra ports such as additional USB and PS/2 ports and sound line-in and line-out ports. |
| Portable Computer | Technically, any computer that features a self-contained screen to allow it to easily be moved around. The first "luggable" portables were as big as a suitcase and had small CRT monitors, then came the with orange gas-plasma screens, and then laptops with LCD screens. Portable computers also usually have their own power source. |
| Portable Document Format | A format developed by Adobe. Adobe makes a freeware Adobe Acrobat Reader program that is available for a variety of platforms. Thus, using a variety of operating systems, you can download and read a PDF document with very little hassle. In addition, the PDF format strives for easy printing, viewing, and compact storage. On PCs .pdf is the file extension for this type of file. |
| Portable Network Graphics | PNG is an image format that uses lossless compression, similar to the GIF format. How the PNG format differs, however, is that the GIF format involves licensing the LZH compression standard from Unisys, whereas PNG is a public domain format that was designed to replace GIFs. Support for PNG is currently included in the current versions of almost all modern browsers. |
| Portable Operating System Interface | A set of operating system interface standards based on UNIX. The standards were developed so that programs could be written more easily that would work on multiple versions of UNIX from different manufacturers. |
| POSIX | A set of operating system interface standards based on UNIX. The standards were developed so that programs could be written more easily that would work on multiple versions of UNIX from different manufacturers. |
| Post Office Protocol 3 | A standard for client/server transmission of e-mail. An e-mail server holds the e-mail, and you use a POP3 client to fetch the mail from a server. IMAP is a newer e-mail client/server protocol with more options. |
| PostScript | A standard language for telling printers how to print text and graphics. Most Macs use PostScript to print, while PCs normally default to PCL. |
| Power Supply | A device attached to the case that converts 120 AC (in the U.S.) to DC at voltages that a computer needs to run. They come rated by wattage. |
| PowerNow! | AMD's power saving technology used in some of its mobile processors. It allows the OS and power management to tune down the speed of the processor in order to conserve power. |
| PowerStep | An Apple/Motorola power management technology that allows PowerPC processors to be tuned down in speed when not plugged in so that power can be conserved. |
| PPGA | The PPGA form factor, also referred to as socket 370, was created by Intel to offer a lower cost alternative to its Slot 1 packaging. It exemplified the first big move back to sockets after L2 caches were embedded in the processor die and cartridges with the chip and separate L2 cache were no longer needed. |
| PPM | This term usually refers to the amount of printed pages a printer can output over a minute's time. The time is based on some average amount of ink or toner coverage on a page. If you are printing complex graphics on inkjet color printers, expect your printer to function more slowly than its PPM rating, as it has to make up to four passes over each area of a page instead of a single pass for black ink only. |
| PQA | A small applet that can be downloaded onto a Palm OS-based PDA that allows for the retrieval of information from the Web. PQAs are intended to minimize the flow of information over a slow wireless connection. |
| Practical Extraction and Report Language | Created by system admin Larry Wall in the mid 1980s, this programming language was originally intended to fill a gap and help out with administration tasks. From those meager beginnings PERL has become a programming language often associated with the Web and UNIX. PERL is the most common programming language used to program CGI scripts. It is a very powerful language that can be used to easily modify large amounts of text files with hardly any programming required. PERL aficionados use it for doing everything. |
| Precision | Precision is how well you define a value. For example, if the value you are representing is 4.321 and you say it's 4.3, you are precise to two places. Numerically, precision is the amount of decimal digits that you are capable of measuring. |
| Precision vs. Accuracy | If the actual value is 4.321 and you say that it is 4.30, then you are precise to the first decimal place but inaccurate by .021. If a value is represented as a bulls-eye on a target, a group of guesses or measurements represented by closely grouped points have a high degree of precision. If that group is near the center, it is highly accurate as well. On a bullseye, think of accuracy as how close to the center your arrow hits, and your measurement of precision as how closely you can group your shots. |
| Preemptive Multitasking | A type of multitasking that allows tasks to be given priority levels. The operating system can then allocate resources to these tasks based on priority level, thus preempting one task from running if a more important task is waiting for a particular resource. |
| Pretty Good Privacy | A freeware program that secures e-mail messages by encrypting and/or adding a digital signature to them. There are also commercial versions of PGP available that encrypt data and offer a wider variety of options. |
| Primary Domain Controller | In Windows NT and 2000 networking, this machine is the main machine that responds to security authentication requests, such as logging in, within its domain. The PDC may be backed by one or more backup domain controllers that can also handle security authentication. |
| Primary partition | A partition that is bootable. You cannot have more than four primary partitions per drive. |
| Print Screen | This button is intended to print whatever is on your screen. If you are using DOS, or you are in your BIOS and have a printer set up, the Print Screen button should do just that. In Windows OSes,hitting the Print Screen button will copy your current desktop so that you can paste it into a graphics program, or a program that will support graphics, such as many word processors today. Additionally, hitting Alt-Print Screen will copy just the window that is active at the time. |
| Print Server | The interface between a printer and a network that allows network clients to connect to the printer and send their print jobs to it. Print servers can be computers, separate hardware devices, or even hardware that resides inside of the printer itself. |
| Printed Circuit Board | The normally green plastic board that is imprinted with one or more layers of circuitry. Examples of common PCBs include motherboards, PCI cards, and AGP cards. The boards can hold microchips and other components, and are a way to link such components together. |
| Printer | Any device that makes an impression on media, usually paper, and is connected to a computer. The invention of the computer with printer has almost made the typewriter obsolete. The simplest printers are located in cash registers printing out receipts, while more advanced printers are capable of magazine-quality photo images. Printers come in several types, including daisy-wheel, dot matrix, inkjet, laser, and dye sublimation. |
| Printer Control Language | A set of commands used to communicate with Hewlett Packard printers. Each printer company has its own language, but PCL has become a generic term to describe these languages. See also Postscript. |
| Private Branch Exchange | A private phone switch used within a company that allows inter-company phone calls without using outside lines. It also connects to one or more outside POTS lines, which are often partitioned off into outgoing lines, incoming lines, or lines that can be used for both purposes. PBXs today use digital connections for inter-company calls, thus you must use digital phones as opposed to standard analog phones (and modems). A PBX is typically a large and costly piece of machinery maintained and/or supported by the company that sold the PBX. There are various options that can be added onto PBXs for call reporting, call management, and voicemail. |
| Processor | Short for Microprocessor. |
| Processor Clock | The processor is regulated by a crystal that vibrates at a regular frequency when an electrical current is applied to it. Each vibration counts as one tick of the clock. |
| Processor Cycle | This is what occurs during one tick of the processor clock. |
| Processor Serial Number | An embedded serial number in Intel Pentium III microprocessors. It allows software manufacturers and websites to identify individuals more precisely. Intel caught a lot of flack for this "feature," and there is no benefit to home users, as websites are not using this technology. Network management could use the software to identify systems, but AMD and other brand microprocessors do not support the PSN--neither do earlier Intel processors. Intel left the PSN out of its Pentium 4 processors. |
| Program | The act of putting together instructions that a computer will follow. Program |
| Programmable Logic Device | An integrated circuit that consists of an array of AND and OR gates whose operation can be modified. The programming of the devices is done by blowing fuses on the PLD. |
| Programmable Read Only Memory | This is a memory device. Once data is written to a PROM it is there forever, unlike with an EPROM. A PROM is also a curious high school ritual involving strangely colored dresses, tuxedos, and sometimes limousines, unconsciously mirroring the wedding rituals most of its participants will undergo at some point in the following 10-15 years. PROMs leave some traumatized and others gleeful, but everyone agrees the post-PROM activities are always better than the PROM itself. |
| Programmed Input/Output | Input/Output standards on IDE hard disk drives. If you have a hard drive that supports one PIO mode, you need your interface to support it as well for maximum performance. The data transfer rates for the various PIO modes are: PIO mode 0 - 3.3Mbps; PIO mode 1 - 5.2Mbps; PIO mode 2 - 8.3Mbps; PIO mode 3 - 11.1Mbps; PIO mode 4 - 16.6Mbps. Ultra IDE doubles the data transfer rate of PIO mode 4. |
| PROM | This is a memory device. Once data is written to a PROM it is there forever, unlike with an EPROM. A PROM is also a curious high school ritual involving strangely colored dresses, tuxedos, and sometimes limousines, unconsciously mirroring the wedding rituals most of its participants will undergo at some point in the following 10-15 years. PROMs leave some traumatized and others gleeful, but everyone agrees the post-PROM activities are always better than the PROM itself. |
| Promiscuous Mode | Although it sounds naughty, as it relates to networking promiscuous mode implies that a network card is able to recognize all network traffic with which it comes in contact. Generally you need a promiscuous mode card using a promiscuous mode driver to run any kind of network packet-filtering tool effectively. |
| Proxy | The use of one computer or device to make requests in place of another over a network. Proxies are often used for Internet security, or to control connections. You can use a proxy or proxy server to pass data between your internal network and the Internet. A machine on your network sends a request to the proxy; the proxy sends the request to a server on the Internet. Thus, it stands in for the computer on your network--the server on the Internet never knows that the request is coming from anywhere but the proxy. Thus 100 machines on your network could all access an Internet server and it would look like the proxy were making all of the requests. Some proxies have caching and site filtering built-in. |
| PS/2 | This is a PC made by IBM that can run OS/2 and DB/2. Of course, it can run anything a normal PC can run, but it's just a nifty IBM naming convention that caught on. |
| PS/2 port | A standard serial port connector used to plug mice and keyboards into PCs. It's got 6 pins and is small and round, compared to the larger 9- and 25-pin serial connectors still found on some PCs. |
| PSN | An embedded serial number in Intel Pentium III microprocessors. It allows software manufacturers and websites to identify individuals more precisely. Intel caught a lot of flack for this "feature," and there is no benefit to home users, as websites are not using this technology. Network management could use the software to identify systems, but AMD and other brand microprocessors do not support the PSN--neither do earlier Intel processors. Intel left the PSN out of its Pentium 4 processors. |
| Public Key Infrastructure | The infrastructure needed to support public key encryption. It requires a certificate authority to issue and verify the public keys, a registration authority that verifies the identity of a person or organization before a key is issued, a certificate directory of the public keys, and a certificate management system. Public key encryption can be used to verify an identity or to encrypt data or messages. |
| Purge | A synonym for deleting something, usually in such a way that it cannot be easily recovered. It is used in several contexts, including the deletion of print jobs from a print queue and the final deletion of files from the NetWare operating system. You can purge print jobs to clean out a print queue that is not behaving, or purge files in NetWare to free up space and fully delete files that were specified for deletion. |
| Push Technology | This technology was first popularized by Pointcast, a company offering a client that would allow data to be "pushed" into it from an external server. The client would then display parts of that data based on what the user was interested in looking at, such as news, weather reports, stock info, and so on. Push technology has lost popularity due to bandwidth requirements and the general undesirability of having data pushed into corporate networks. Now the same services are offered through standard Web pages. |
| PVC | see Permanent Virtual Circuit or Polyvinyl Chloride |
| PWL | This is a type of file ending in the .pwl extension. Windows 3.x/95/98 uses encrypted .pwl files to save the local user's system passwords. PWL translates fairly directly into PassWord List, or Listing. |
| Q-Bert | A mid 1980s arcade game that involved a fuzzy red creature jumping from cube to cube, trying to avoid a purple snake named Coily. |
| QoS | An effort to provide different prioritization levels for different types of traffic over a network. Various methods are used to achieve quality of service, including the RSVP protocol. For example, streaming video may have a higher priority than ICMP traffic, as the consequences of interrupting streaming video are more obvious than slowing down ICMP traffic. |
| Quake | This was a revolutionary 3D, first-person perspective game full of blood and gore. Designed by id Software, it is now perhaps the most well-known and most user-modified line of 3D shooter games. Other competitors include the Unreal series and Doom (also from id Software). |
| Quality Assurance | The practice of checking hardware, software, or systems for defects, identifying such defects, and then checking to make sure that such defects are corrected when future revisions of software or hardware are ready for testing. QA workers typically work closely with the people who develop hardware and software, and often program exhaustive scripts to automate checking and identify problems. |
| Quality of Service | An effort to provide different prioritization levels for different types of traffic over a network. Various methods are used to achieve quality of service, including the RSVP protocol. For example, streaming video may have a higher priority than ICMP traffic, as the consequences of interrupting streaming video are more obvious than slowing down ICMP traffic. |
| Rack | A metal frame used for holding server computers and networking equipment. A standard rack is 19" wide. There are wider racks that are 23" wide, built to hold wider equipment. Racks range in height, but are typically either 24 or 42 rack units, with each unit being 1.75". |
| Rack Units | This refers to the distance of 1.75" between screw holes in a rack used to hold server equipment. Most computer equipment racks are between 24 and 42 rack units in height. If you are shopping for rack equipment, keep in mind the height of the rack you have to work with and the "U" rating of the equipment. Heights of 1U indicate equipment that can fit into a 1.75" tall rack space, and 2U would indicate twice that at 3.5", and so forth with 3U, 4U, and up. |
| Radio Button | A GUI term denoting that the user has a group of selections to make, and that he or she can only make one selection at a time. As it relates loosely to a radio, you can only listen to one station at a time. In the computer world, an example of where a radio button may be used is on a website where you need to pick which type of payment you're using: Visa, Mastercard, Discover, or AMEX. Usually you'll have radio buttons, and you can pick only one method of payment. Radio buttons are represented by a group of small circles. When you click on one of them you get a dot on your selection. There is always a default selection. |
| Radio Frequency | The range or frequencies between 10 kilocycles per second to 300,000 megacycles per second in which radio waves can be transmitted. It can also refer to a frequency used for a specific radio station. |
| RAID 0 | Also known as disk striping, this form of RAID combines two or more hard drives into a single logical drive. Any data is written in blocks first to one drive, then the next, and so on. A RAID 0 configuration sacrifices redundancy for raw speed. The more drives you use the faster your logical drive will be. The space available on the logical drive is the sum of space on all of the drives used, assuming that all drives are the same size. If drives are of disparate sizes, RAID 0 generally only uses a piece of the drive equal to the smallest drive. Of course, if one drive dies, you lose all of the information on the entire RAID. Use RAID 0 with care. |
| RAID 1 | There are two forms of RAID 1: disk duplexing and disk mirroring. Disk mirroring involves two hard drives that are on the same drive controller. The same data is written to both drives, so write operations are slower because you must write data to two drives. Read operations are the same speed, as if you only had one drive. Disk duplexing is much like disk mirroring, but each drive is on a separate controller. This speeds up the normally slow write operations and also adds an additional level of redundancy, in case one of your controller cards dies. With RAID 1 you get half the space you paid for because you're writing twice as much data. |
| RAID 10 | This form of RAID was originally called RAID 1+0, and is now commonly referred to as RAID 10. This is basically a bunch of RAID 1 drives linked together with RAID 0. Hence you get the speed benefits of RAID 0 with the redundancy benefits of RAID 1. The only problem is that you use a lot of drives to do it. Like RAID 1, you only get half of the space that you've paid for. Of course it may be worth it if you can rest easier at night. RAID 10 is generally a bit faster than RAID 5. |
| RAID 2 | This form of RAID protection stripes data across two or more drives, and also stripes an ECC parity code across one or more drives. This code is used to verify that the data read and written is correct. As more data drives are used, you want to increase the number of parity drives to increase performance. This RAID type is not often used. |
| RAID 3 | A form of RAID protection that uses at least three drives, where one drive holds all of the parity data. The other two or more drives contain data striped across them in bits or bytes. This RAID type is not often used. |
| RAID 4 | This is similar to RAID 3 in that an extra drive is used to store all parity information. However, data is striped by drive sector instead of by bits or bytes, so that read operations are faster. This RAID type is not often used. |
| RAID 5 | A RAID 5 configuration utilizes three or more hard drives and stripes the data across them, much like RAID 0. The difference is that parity information is striped across the drives as well, so if you lose any one drive the information can be reconstructed from the parity information. For example, with three drives the first stripe is data (on drive 1), data (on drive 2), parity (on drive 3); then data, parity, data; then parity, data, data. This pattern continues. If one drive fails, you get a mix of parity and data on the remaining two drives, and you can reconstruct all of the data. Of course, before the data is reconstructed the RAID operates in "degraded mode" and is slow. To reconstruct the data you must remove the failed drive and replace it with another, or use a "hot spare." During reconstruction the array continues to be slow. Once the RAID is reconstructed performance returns to normal levels. RAID 5 performance is similar to RAID 0 performance, but a bit slower due to the parity information. Performance increases, like RAID 0, when more drives are added. With RAID 5 you get most of the space that you've paid for, minus one drive's worth. A common option with RAID 5 is the hot spare, where a drive sits idle until needed. If you lose a drive, the hot spare takes over and the RAID is rebuilt automatically. Of course you still get the performance penalty during the rebuilding stage, but it can be set to happen automatically. |
| RAM | A type of memory chip that can be written, read, and re-written. You can write to any part of it, thus the "random access" in the term. The slang term RAM refers to a computer's main memory, or the physical RAM chips installed in the system. |
| Rambus DRAM | One possible future successor to SDRAM, and competitor to DDR SDRAM. DRDRAM (also now simply called RDRAM) was originally developed by Rambus, Inc. This RAM architecture is capable of speeds starting at 266, 356, and 400MHz, and transfers data on the up and down ticks of a clock cycle, where standard SDRAM tops out at about 200MHz. You may see RDRAM referred to at 532, 712, and 800MHz, but that is actually 266*2, 356*2, and 400MHz*2, where the *2 denotes transfer on the up and down tick of the clock. Intel picked RDRAM to be the future of RAM for PCs, but RDRAM ran into many stumbling blocks due to the complexity of manufacturing it. RDRAM was used in the popular Nintendo 64 game machine for its high-speed capabilities and low pin count, necessary for the intense 3D rendering being done on a low complexity system. RDRAM started out using a 16- bit bus, while SDRAM and DDR have 64-bit buses. Thus, 100MHz SDRAM has half the throughput of RDRAM at 400MHz (100*64 = 6,400Mbits/second; 400*2*16 = 12,800Mbits/second). However, newer RDRAM uses a 32-bit bus and is clocked up to 533MHz*2. Still, it never achieved dominance in the PC market. |
| Rambus In-line Memory Module | The form factor for Rambus RDRAM. By comparison, SDRAM is mainly found on DIMMs, and EDO RAM is usually on SIMMs. RIMMs require that if you do not fill all RIMM slots with RDRAM memory you must keep the empty slots filled with termination boards to ensure that the high speed Rambus memory signals do not bounce improperly. |
| RAMDAC | The part of a graphics card that transfers the digital color signals into analog signals that a CRT monitor can understand, or to digital signals that LCD monitors can interpret. Faster RAMDACs are necessary if you want to use higher resolution displays at higher color and refresh rates. |
| Random Access Memory | A type of memory chip that can be written, read, and re-written. You can write to any part of it, thus the "random access" in the term. The slang term RAM refers to a computer's main memory, or the physical RAM chips installed in the system. |
| Rar | The file extension of a type of compressed file created by the WinRAR program by RarSoft. It is considered by many to be more versatile than other compression programs on the market such as WinZip, has a better compression ratio, and is used by many to send archived data over the Internet due to its superior compression in many circumstances. |
| RAS | see Remote Access Services or Remote Access Server |
| Raster Graphics | This form of graphics is probably what you are looking at now. Composed of pixels on a bitmap, it allows for solid colored objects and graphics as we know them. See also vector graphics. |
| Raster Operation | A set of low-level graphics operations in Windows, i.e., operations that deal with raster graphics. |
| Raw | Any data that has not been translated. It also refers to sending print data directly to a printer instead of translating it first to an EMF file. Printing to raw format uses less CPU power for translation, but skips the print spooler and makes printing more dependent on the application and less on the OS. |
| RCA cables | The standard, single-ended analog cables used to connect audio and video devices to each other. Typically a red input is for the left channel of sound, white is for the right, and yellow is for compsite video. RCA cables are typically thin, and give good results for cable lengths of 20 feet or less. For lengths over 20 feet the unbalanced signals in an RCA cable can degrade and are susceptible to hum and noise interference. Thus, for longer runs with professional equipment, TRS or XLR cable should be used. |
| RDRAM | One possible future successor to SDRAM, and competitor to DDR SDRAM. DRDRAM (also now simply called RDRAM) was originally developed by Rambus, Inc. This RAM architecture is capable of speeds starting at 266, 356, and 400MHz, and transfers data on the up and down ticks of a clock cycle, where standard SDRAM tops out at about 200MHz. You may see RDRAM referred to at 532, 712, and 800MHz, but that is actually 266*2, 356*2, and 400MHz*2, where the *2 denotes transfer on the up and down tick of the clock. Intel picked RDRAM to be the future of RAM for PCs, but RDRAM ran into many stumbling blocks due to the complexity of manufacturing it. RDRAM was used in the popular Nintendo 64 game machine for its high-speed capabilities and low pin count, necessary for the intense 3D rendering being done on a low complexity system. RDRAM started out using a 16- bit bus, while SDRAM and DDR have 64-bit buses. Thus, 100MHz SDRAM has half the throughput of RDRAM at 400MHz (100*64 = 6,400Mbits/second; 400*2*16 = 12,800Mbits/second). However, newer RDRAM uses a 32-bit bus and is clocked up to 533MHz*2. Still, it never achieved dominance in the PC market. |
| Read Only | This means that the object cannot be written to, which means that you can't save any modifications you make to it. An operating system can have a file set to read-only for security purposes, or certain media, like a CD-ROM or DVD-ROM, is read-only by design and cannot be altered. |
| Read Only Memory | Memory containing a program, data, or information about the device that has been programmed onto the chip at the factory and cannot be changed. There is no easy mechanism to write to ROM, but it is usually possible to do it. It's just not made easy, as writing to ROM is not intended to done. |
| Real-time | Tasks that are time-critical and must happen in our time (as opposed to the much faster computer time). Real-time is the highest priority you can give to a thread or process in the Windows environment. Even though this is accounted for in the operating systems, Windows has historically been a poor real-time OS. The user interface should always be real-time. If you move the mouse, your pointer should move on screen immediately. Unfortunately, Windows can bog down enough so that this doesn't happen. Other real-time applications can include medical applications and control of real world systems. For example, you want to make sure that the train switches tracks on time and not too late because your server is bogged down. |
| Reboot | To restart a computer. It comes from "boot," which is a term that means starting the operating system on the computer. When you are using your computer and have weird problems, the tech guy comes over and says, "Time to reboot." If you are the tech guy you'll find yourself saying this far too often. |
| Reception | The act of downloading or receiving data. Often, the term "RX" is used on indicator lights on modems or network cards to indicate that data is flowing into the device. |
| Recommended Standard 232 | This is the de facto standard for communication through PC serial ports. It can refer to cables and ports that support the RS-232 standard. Common usage would include, "Hey, Jimmy! Why don't you take your RS-232 cable and stick it right in your RS-232 port!" |
| Recursion | A programming term describing a process that defers its operations as it runs, growing in memory size. Once all operations are deferred, there is a computation process that runs through the operations and figures out the values. If a recursive process is interrupted, there is not any easy way to recover it, as the operation is constructed on the fly with no fixed amount of variables. Contrast this to an iterative process. |
| Recursive | A programming term describing a process that defers its operations as it runs, growing in memory size. Once all operations are deferred, there is a computation process that runs through the operations and figures out the values. If a recursive process is interrupted, there is not any easy way to recover it, as the operation is constructed on the fly with no fixed amount of variables. Contrast this to an iterative process. |
| Red Hat Package Manager | A packaging system based on files with the .rpm extension that contain dependency information, pre- and post-install scripts, and the actual user runtimes (files/executables) that are part of the package. Windows users might think of this as an .msi file commonly used to hold pre-installation data. |
| Reduced Instruction Set Computing | This type of chip use a simpler instruction set than CISC chips to get its work done. This results in more instructions that need to be processed by the processor, but they are easier to process and regular in size, so the chips can process more instructions per clock cycle than a CISC chip. Chip philosophers argue the benefits of RISC vs. CISC, but there is no clear cut winner. See also CISC for additional info. |
| Redundancy | In a redundant system, if you lose part of the system, you can continue to operate. For example, if you have two power supplies and one takes over if the other one dies, that is a form of redundancy. You can take redundancy to extreme levels, but you spend more money. Redundancy is one reason that high-end server machines cost 10 times more than desktop PCs. |
| Redundant Array of Inexpensive Drives | A method of linking storage devices together so that they function as a single logical unit. RAID requires all drives to be of the same size, as compared to JBOD setups. RAID can be used for increased performance, but is also used to increase redundancy. |
| Refresh Rate | This is how often something is rewritten or updated. With CRT monitors, the refresh rate of the screen is very important to provide an image that appears stable when viewed closely. Any refresh rate under 75Hz is considered inadequate. Most CRT monitors today can work at rates of 75Hz and over in all of their supported resolutions, but that was not always the case. The refresh rate of the monitor is also controlled by your video card, which can be another limiting factor. |
| Register | A CPU contains registers that it uses for temporary storage of data. You can think of a register as a kind of L0 cache. If the processor has to add the values of two memory locations, it may first fetch each from memory and place them into its registers, and then do an operation that adds the two registers together. |
| Registry | This was first introduced in Microsoft's Windows NT, and then to consumers with Windows 95, as a centralized repository for all the miscellaneous settings that were stored in .ini files in Windows 3.x. Now, all current versions of Windows contain a Registry. Managing the Registry is better than managing a group of .ini files, but still has many problems. |
| Relative URL | An URL that does not include strict directory information; instead, you give the link directions like "back two directories and up one directory" in standard command line format like "../../imagedir/image.jpg". This way you can change domain names or IP addresses of your webserver and not have to recode your HTML pages. However, if you change directory names (or depth), you must change even your relative URLs. |
| Release Engineer | The individual whose job it is to oversee the mechanics of the development process of software. The release engineer controls when new code is entered into the current working release, and makes sure the proper pieces of code are compiled and ready when the program has to be sent to a media duplication plant, or simply made live on a network. |
| Remote Access | A means of contacting a remote network and becoming a node on that network. The problem with remote access is that the connection to the network is generally slow, such as over the Internet, so copying or working with large files is slower than when you are directly connected. The advantage is that the minimum hardware requirement is one server or remote access piece of hardware that can control many remote access lines. See also remote control. |
| Remote Access Server | A general term for any server that offers remote access to a network over phone line, WAN link, or even over a LAN. |
| Remote Access Services | A Microsoft service first included with Windows NT 3.51 that allows access to a network over a phone line, WAN link, or LAN. |
| Remote Control | A means of taking control of a remote computer, usually on a remote network. Programs like Symantec's pcAnywhere and a host of others offer this ability. Usually you connect to the remote computer via the Internet or a phone line, and control the computer by interacting with your computer while seeing on your screen a representation of what is actually happening on the remote computer. The downside to remote control is that each remote connection requires a separate computer. You can't easily have multiple people controlling one computer remotely and seeing a useful representation of what is on the remote display. See also remote access. |
| Remote Monitoring | Part of the MIB that is used in SNMP. RMON defines 9 types of information that can be used to monitor networks and network devices. RMON2 is an extension of the RMON specification. |
| Remote Procedure Call | A method a program can use to make a call to another program across a network without specifically dealing with network protocols. It is often used for printing across a network. |
| Removable Canister | A removable hard drive casing. There are two parts to the canister: the bay itself, and the casing that goes around the hard drive. These canisters can be used with SCSI or IDE/ATA hard drives, and have the advantage of easy portability of hard drives, especially if you have multiple computers with the same type of bay in them. Integrating a bare hard drive into a removable canister can be an annoying chore, as space is limited and you have lots of extra wires to deal with. This term can also be used to refer to the hard drives that are used in server machines and integrated into cases that can be plugged into servers and removed easily. Removable canisters can be hot pluggable, but usually only in servers with RAID systems. |
| Removable Storage | This type of storage allows you to remove the actual storage media from a drive and replace it with other media. DVD-ROM, CD-ROM, floppy drives, and Zip drives are all forms of removable storage. |
| Render | This synonym for hacking up animals for human consumption determines how colors are used on each triangle displayed in a 3D image. Very complex images take a long time to render; less complex 3D images, such as those in a 3D game, can be rendered in real time. When they make computer animated movies or effects of very high quality, effects companies use many computers to render images. |
| Repeater | A device used to repeat a signal to send it further away or to many more devices. The earliest network hubs are also called repeaters, as they had no switching capabilities but would only repeat the same signal to all ports. |
| Report Program Generator | A programming language for minicomputer mainframes such as the IBM AS/400. RPG began as a program to generate reports--as you could have guessed from the name--but is now a full programming language that is widely used. |
| Request For Comments | A document that was created to define accepted or proposed Internet standards or standards of practice. The acceptance of a document as an RFC is governed by the IETF (Internet Engineering Task Force). RFCs begin life as Internet-Drafts, which may be written by anyone. The IETF decides which Internet-Drafts become RFCs. RFCs are most often created by groups of interested individuals hoping to create a standard for interoperability over the Internet; however, they also describe such suggested practices, such as how to set up a mailserver to avoid being used to transmit SPAM mail. |
| Reseat | The disconnection and reconnection of an add-on board, memory, processor, hard drive, or other accessory. The reason for reseating an accessory is usually to test whether it is connected properly in the first place, and to ensure that it is not the source of computer problems. |
| Reseller | Anyone who buys computer equipment or software and sells it. In most states in the U.S. you need a reseller license to purchase goods without paying taxes, and then you are responsible for collecting and paying taxes on the goods you resell. The combined entity of all the resellers makes up the channel. Resellers usually buy goods from large distributors and sell them to companies or consumers. |
| Resistor | A two-terminal electronic component that resists an electrical current and turns the extra current into heat. Resistors are rated in ohms, and can be used to regulate the voltage and current in a circuit. Basically, a resistor resists the flow of electricity. Resistors are used to lower voltages and currents so that components that require smaller voltage/current can function properly. If a power supply puts out 12 volts and you have a chip that runs on three, you need a resistor to cut down the voltage. |
| Resolution | The amount of pixels that are displayed on a screen measured in pixels horizontal by pixels vertical, such as 1024 x 768. The higher the resolution, the more pixels can be displayed at any one time. With CRT monitors it's possible to have several native resolutions, but with LCD screens there is one native resolution, and lower resolutions are interpreted and may lose detail. When you use a higher resolution in the same space you pack more pixels per inch into that space, and can thus display more information at once, expanding your desktop. |
| Restart | The process of an operating system on a computer shutting down, and then starting back up automatically. During a restart the user does not need to hit the power switch. |
| Retention Mechanism | This typically refers to the mechanisms attached to a motherboard that hold onto a Slot 1, Slot 2, or Slot A cartridge so that it doesn't come loose during usage or shipping. The mechanism is usually made of black plastic, and holds the processor cartridge in place. |
| Reverse Engineering | The process of understanding a system without knowing how the system actually functions internally, but only judging how the system responds to various inputs. In that way a company can create a product with similar or equivalent behavior to another company's product without infringing on that company's patents. |
| Revolutions per Minute | A measurement that applies commonly to hard drives, and removable drives like CD-ROMs and DVD-ROMs. It also applies to anything that moves in a circular motion. If you are using a drive with higher RPMs, you usually have better performance. Since the disk is spinning faster the drive can usually read data at a faster rate. For example, 5,400 RPM hard drives are generally slower than 7,200 RPM hard drives. The downside to higher RPM rates is that it is harder to stabilize and read data from a disk that is spinning faster, so the mechanism may be more complex and more expensive. Also, faster spinning drives are usually louder and run hotter. |
| Rewriteable | This means that what was written can be erased so that it can be written to again. CD-R media is not rewriteable, but CD-RW media is. It is also more expensive. Floppy disks and hard drives are rewriteable as well. |
| RFC | A document that was created to define accepted or proposed Internet standards or standards of practice. The acceptance of a document as an RFC is governed by the IETF (Internet Engineering Task Force). RFCs begin life as Internet-Drafts, which may be written by anyone. The IETF decides which Internet-Drafts become RFCs. RFCs are most often created by groups of interested individuals hoping to create a standard for interoperability over the Internet; however, they also describe such suggested practices, such as how to set up a mailserver to avoid being used to transmit SPAM mail. |
| Rich Media | A type of Internet advertisement that allows for more interaction than a simple click. It may incorporate a useable dropdown menu, radio buttons, or even Flash or Shockwave animation and sound. Some plain graphic ad banners appear to be rich media, but when clicked on they do not interact with the user, merely forwarding the user to a different website using a standard image and link tag. |
| RIMM | The form factor for Rambus RDRAM. By comparison, SDRAM is mainly found on DIMMs, and EDO RAM is usually on SIMMs. RIMMs require that if you do not fill all RIMM slots with RDRAM memory you must keep the empty slots filled with termination boards to ensure that the high speed Rambus memory signals do not bounce improperly. |
| Ring topology | A network that is connected on both ends to one source, with client machines hanging off of the ring. If you break the ring, all computers in the ring lose connectivity. |
| Rip | The action of copying music track(s) off of a music CD, and also possibly converting them into some form of compressed file, typically MP3. |
| RISC | This type of chip use a simpler instruction set than CISC chips to get its work done. This results in more instructions that need to be processed by the processor, but they are easier to process and regular in size, so the chips can process more instructions per clock cycle than a CISC chip. Chip philosophers argue the benefits of RISC vs. CISC, but there is no clear cut winner. See also CISC for additional info. |
| Riser Card | A card that plugs into a motherboard and enables other cards to be plugged into it horizontally. Architectures that support riser cards are typically designed to allow tall cards to be plugged into shorter enclosures. Servers often use riser cards, since if they didn't the motherboard would be too large to fit into a standard sized enclosure. |
| RMON | Part of the MIB that is used in SNMP. RMON defines 9 types of information that can be used to monitor networks and network devices. RMON2 is an extension of the RMON specification. |
| RMON2 | An updated specification for RMON that was finalized in 1997 as RFC 2021. It includes 10 additional types of information that can be monitored and collected, adding onto the original 9 of RMON. |
| RMS | Mathematically, this refers to the square root of the average of a group of numbers. You will most often see RMS referring to the power rating of an audio amplifier. RMS power is different than peak power, and is a more accurate rating of power than peak. If an amplifier lists a power rating in watts and doesn't say whether it is RMS or peak, you can assume it is peak, as peak ratings are typically much higher than RMS power. Manufacturers of high quality audio components will always list the RMS power of their amplifiers. |
| ROB | A tall, bearded, long-haired person who is scarily intelligent and often dangerous (ROBs have been known to be photographed with axes and chainsaws). A ROB normally likes to drive really fast cars and eat lots of pizza. ROBs also frequently contribute nearly 100% of the content of on-line Internet webzines. |
| Robot | Besides being a mechanical device used to mimic human form, usually to accomplish some repetitive task, this term refers to a computer program that scans Web pages and links. Like a similar spider program, robots are used to scan Web pages and index them. You can insert a file called robots.txt to the main directory of your website to tell the robots which directories not to index. |
| ROFL | Online speak for "Rolling On The Floor Laughing." |
| ROM | Memory containing a program, data, or information about the device that has been programmed onto the chip at the factory and cannot be changed. There is no easy mechanism to write to ROM, but it is usually possible to do it. It's just not made easy, as writing to ROM is not intended to done. |
| Root | In UNIX this refers to the main system user who has full access to all files on a system. It also refers to the base directory of a file system. |
| Root directory | The base directory of an operating system. This term is typically used for the UNIX OS, but can apply to a webserver as the directory to which a browser defaults. It refers to the directory represented by a slash, or "/", character in UNIX, or a "" character in Windows. To change to the root directory use the command "cd /" in UNIX or "cd " in Windows. |
| Root Mean Square | Mathematically, this refers to the square root of the average of a group of numbers. You will most often see RMS referring to the power rating of an audio amplifier. RMS power is different than peak power, and is a more accurate rating of power than peak. If an amplifier lists a power rating in watts and doesn't say whether it is RMS or peak, you can assume it is peak, as peak ratings are typically much higher than RMS power. Manufacturers of high quality audio components will always list the RMS power of their amplifiers. |
| ROP | A set of low-level graphics operations in Windows, i.e., operations that deal with raster graphics. |
| RPC | A method a program can use to make a call to another program across a network without specifically dealing with network protocols. It is often used for printing across a network. |
| RPG | A programming language for minicomputer mainframes such as the IBM AS/400. RPG began as a program to generate reports--as you could have guessed from the name--but is now a full programming language that is widely used. |
| RPM | see Revolutions Per Minute or Red Hat Package Manager |
| RS-232 | This is the de facto standard for communication through PC serial ports. It can refer to cables and ports that support the RS-232 standard. Common usage would include, "Hey, Jimmy! Why don't you take your RS-232 cable and stick it right in your RS-232 port!" |
| RTM | Online speak for "Read The Manual." A more excited version of this is RTFM. |
| Runtime | The time when a program or process is being executed. When it's running it may need runtime libraries and have runtime variables with runtime values. The term is also used to refer to runtime versions of software that include functionality of the software as the means to an end of running some other software, such as packaging a DOS program with a runtime version of DOS so that you don't even need DOS on your computer to run the program. |
| Runtime Error | An error that happens when a program is executed. When you run/execute a program and get a runtime error, that means that there is as error in the program that was not or could not be detected by the compiler when the program was initially compiled. |
| Runtime Library | A group of programming functions that are called when a program is run, as opposed to being embedded into the program when it is compiled. |
| S-Video | A video cabling standard that splits video information into two separate signals: one for brightness (luminance), and the other for color information (chrominance). In contrast to composite video, S-Video has a sharper picture. Nowadays, DVD players, some VCRs, and many high-end televisions support S-Video. S-Video is also supported by many electronic accessories, such as camcorders, computer video cards with TV functions, and even console games such as the Sony PlayStation. |
| S.M.A.R.T. | This technology reports on a variety of hard drive attributes. You need a compliant BIOS and SCSI and/or IDE controller, a hard drive that supports SMART, and some sort of software package that reports on these conditions. Once you have that you should be able to receive system warnings about your hard drive. Many hard drive manufacturers have added onto the SMART technology or changed it around so that it has proprietary features for their drives. The good news about SMART is that having SMART is much better than not having it, and you can be warned of hard drive failure before it happens and backup your drive while it still works. Thus, your data is safer with SMART around. |
| Safe Mode | An operating mode used in Microsoft operating systems. It was first introduced in Windows 95 and was loaded automatically if Windows 95 crashed during boot up. You can access Safe Mode if you press the "F8" key when new Windows operating systems are booting--this will bring you to a menu that allows you to boot into safe mode. Safe Mode boots the operating system with minimal driver support. The purpose of it is to help resolve boot problems. For example, if you install the wrong graphics driver, Windows could crash when it's loading. When you restart Windows it will boot into Safe Mode and use the standard VGA driver with 60Hz refresh rate. This will allow you to go to the Display Properties function and switch the video driver back to something that works. There is no reason to go into Safe Mode unless you are crashing during boot-up or you are trying to diagnose a driver problem. |
| Sample | A small portion representative of something. It usually means a small amount of sound from an instrument, enough to reproduce the sounds of that instrument. |
| SAP | This protocol is used on NetWare networks to advertise available network services. For example, a NetWare server uses SAP to let other computers know that it's offering up some shared files. This also stands for "Standard Accounting Program," a program on which some large businesses run their accounting. |
| SATA | A specification for consumer hard drive connections that boosts the data transfer rate up to 150MB/second. In addition, it changes IDE/ATA from a parallel interface requiring 40 separate wires to connect components to a serial interface requiring only 6 wires. 2x and 4x versions of Serial ATA double and quadruple the speed of Serial ATA. |
| Save | This term describes the movement of data from a computer's volatile DRAM to the non-volatile hard disk or other media. Basically, when you save something you are making sure that if your computer loses power you will be able to get back to the information that you have saved. This information may be saved to a floppy disk, a hard drive, or a CD-R. The information also can be saved to these devices connected to your local machine, or to a server on a network. |
| SC242 | A 242-pin connection form factor after which Slot 1 and Slot A cartridges and connections are modeled. |
| SC330 | A 330-pin connection form factor after which Slot 2 and Slot B cartridges and connections are modeled. |
| Scalability | The ability to grow with your needs. A scalable software package means that you only buy the parts you need, and that it has the ability to grow by adding on as you do. |
| Scalable | Applications or systems that are able to scale to large amounts of users. For example, a database that completely locks out every other user when someone is using it is NOT scalable. The computer system that runs ATM and bank transactions must be highly scalable. It is often misspelled as "Scaleable," and is used in many product names. |
| Scalar | This value, in mathematical terms, is any single real (not imaginary) number. The term superscalar is used by the semiconductor industry and refers to the ability to issue multiple instructions in a single clock cycle. Just think of scalar as a single number and you can see how this term was derived. See also vector and superscalar processor. |
| Scandisk | A Microsoft program that first shipped with DOS version 6, replacing the venerable chkdsk.exe program. Technically the program is scandisk.exe. It is available in MS-DOS version 6.x, and non-NT versions of Windows. It added the ability to do a surface scan for physical defects on drive media, and a nicer UI than chkdsk, which had no graphical UI. Windows NT/2000/XP still uses chkdsk. |
| Scanner | A device used to copy an image from a physical source (e.g., a photograph) into a computer. |
| Screensaver | A program that displays an image, animation, or just a blank screen on a computer after no input has been received for a certain length of time. Screensavers were originally designed so that images would not be burned into the phosphors of older CRT screens, but soon turned into a source of entertainment. Complex screensavers can use a good deal of CPU power to run, and should be kept off of servers. Screensavers are largely unnecessary today as CRT screens are much more resistant to burn-in. |
| Script | A group of commands usually stored in a file and run one at a time so that you don't have to type them in one at a time. Script is the newer, sexier term for batch. Don't talk about batch files anymore! It's all scripts and scripting languages. We're on the INTERNET, for goodness' sake! |
| Scroll Lock | The scroll lock key is, for most, a way to turn the "scroll lock" light on and off on your keyboard and nothing more. The scroll lock key was intended to function as a third "state" key, such as the Caps Lock and Num Lock keys. Some software makes use of it, but most does not. Some people mock the scroll lock key, but we seek ways to unleash its power! :P |
| SCSI | Pronounced "skuzzy," this is a standard data pathway used mostly for hard drives and CD-ROM drives; but it was also a common interface for scanners and even printers at one point. It is the fastest (and the most flexible) method of interfacing with hard drives. It comes in numerous varieties, and is mainly used in servers and high-end workstations. SCSI drives are much more expensive than IDE drives, but SCSI drives can have features, like 15,000 RPM spin speeds and 5-year warranties, that IDE drives currently do not. |
| SCSI bus termination | Because of the amount of signals that SCSI format sends through small wiring, termination is required. The termination is accomplished by using resistors across certain signal wires. If the chain were not terminated, the signals would bounce off the end of the chain and cause interference with real signals. |
| SCSI Configured Auto-Magically | This SCAM is actually a good thing. It allows SCSI devices to automatically (or automagically--don't make me barf) be configured with an ID number, even if they aren't assigned one. This makes adding SCSI devices much easier. You don't have to fool around with a bunch of jumpers or worry about assigning two devices to the same ID--everything is done for you. |
| SCSI Termination | Because of the amount of signals that SCSI format sends through small wiring, termination is required. The termination is accomplished by using resistors across certain signal wires. If the chain were not terminated, the signals would bounce off the end of the chain and cause interference with real signals. |
| SCSI-2 | This version of SCSI originally came in two varieties: Fast-SCSI 2 and Fast-Wide SCSI 2. Recent extensions to the SCSI 2 specification include Ultra SCSI and Ultra2 SCSI. Ultra3 SCSI is now called Ultra 160M. |
| SCSI-3 | The SCSI 3 specification doesn't technically exist, but SCSI-3 is often used to describe the Ultra SCSI standard. Before the time of Ultra SCSI, SCSI-3 was a misnomer for Fast Wide SCSI-2. |
| Scuzzy | This is how the abbreviation SCSI is pronounced. Pronounced "skuzzy," this is a standard data pathway used mostly for hard drives and CD-ROM drives; but it was also a common interface for scanners and even printers at one point. It is the fastest (and the most flexible) method of interfacing with hard drives. It comes in numerous varieties, and is mainly used in servers and high-end workstations. SCSI drives are much more expensive than IDE drives, but SCSI drives can have features, like 15,000 RPM spin speeds and 5-year warranties, that IDE drives currently do not. |
| SDK | A programming tool that is tailored towards a particular purpose. The kit includes a compiler, linker, and an editor. Most hardware manufacturers have SDKs available that work specifically with their hardware. For example, if you were writing a program to work with a SoundBlaster card, you'd want to get the SoundBlaster SDK from Creative Labs. |
| SDRAM | This is like Fast Page mode DRAM, but arranged with a more efficient data pathway that allows for faster throughput. |
| SDSL | A form of digital subscriber line that has the same transmission speed upstream and downstream. It is most often used for business use, and is more expensive than the consumer version, ADSL. |
| SDX | This technology was introduced by Western Digital. The idea behind it is that slower drives such as CD and DVD drives would attach directly to larger, faster hard drives. There would be a 10-pin connector between the hard drive and the other peripheral, as opposed to the 40-pin IDE connector. A portion of the hard drive would be used as cache for the CD drive or other device. This was touted to speed up CD-ROM drives by 50%-300% depending on what operations are being performed. You would have had to buy specialized hard drives and CD drives to take advantage of this technology, but it flopped, so don't worry about it. |
| Seat | The installation of memory or other accessories into a computer. It can also be used as a noun to describe a single license, or a single client workstation for licensing purposes. |
| SECC | The SECC is a processor cartridge designed to hold Intel's Pentium II and some external cache. It then plugs into a motherboard that supports Slot 1. This was replaced by SECC2 in some Pentium II 450s and all Pentium IIIs. SECC2 is a smaller and more cooling-efficient design, allowing the processor to come in direct contact with a heatsink. |
| SECC2 | The SECC is a processor cartridge designed to hold Intel's Pentium II and some external cache. It then plugs into a motherboard that supports Slot 1. This was replaced by SECC2 in some Pentium II 450s and all Pentium IIIs. SECC2 is a smaller and more cooling-efficient design, allowing the processor to come in direct contact with a heatsink. |
| Sector | A piece of a track of a hard drive or other disk media. Each track is split up into groups of sectors. |
| Secure HyperText Transfer Protocol | A secure means of transferring data using the HTTP protocol. Typically HTTP data is sent over TCP/IP port 80, but HTTPS data is sent over port 443. This standard was developed by Netscape for secure transactions, and uses 40-bit encryption ("weak" encryption) or 128-bit ("strong" encryption). If you are at a secure site, you will notice that there is a closed lock icon on the bottom area of your Navigator or IE browser. The HTTPS standard supports certificates. A webserver operator must get a digital certificate from a third-party certificate provider that ensures that the webserver in question is valid. This certificate gets installed on the webserver, and verifies for a period of a year that that server is a proper secure server. |
| Secure Sockets Layer | A protocol specified by Netscape that allows for "secure" passage of data. It uses public key encryption, including digital certificates and digital signatures, to pass data between a browser and a server. It is an open standard and is supported by most modern browsers. |
| Self-Monitoring Analysis and Reporting Tool | This technology reports on a variety of hard drive attributes. You need a compliant BIOS and SCSI and/or IDE controller, a hard drive that supports SMART, and some sort of software package that reports on these conditions. Once you have that you should be able to receive system warnings about your hard drive. Many hard drive manufacturers have added onto the SMART technology or changed it around so that it has proprietary features for their drives. The good news about SMART is that having SMART is much better than not having it, and you can be warned of hard drive failure before it happens and backup your drive while it still works. Thus, your data is safer with SMART around. |
| Semiconductor | A substance (usually silicon doped with germanium or arsenic) that selectively conducts electricity. The selection usually occurs by running another current through a different axis to turn current flow on or off. Microprocessors are made of semiconductive materials. |
| Serial | A means of operation meaning in series, or one after the other. It refers to connection standards that use a single wire. See also parallel. |
| Serial ATA | A specification for consumer hard drive connections that boosts the data transfer rate up to 150MB/second. In addition, it changes IDE/ATA from a parallel interface requiring 40 separate wires to connect components to a serial interface requiring only 6 wires. 2x and 4x versions of Serial ATA double and quadruple the speed of Serial ATA. |
| Serial Line Internet Protocol | A protocol used to connect your computer to the Internet using a serial connection, such as over a dial-up modem. SLIP isn't used often anymore, as PPP has become a much more popular method of providing dial-up connections. |
| Serial Port | A data port/connection standard that is usually used to connect modems and mice. It comes in 9- and 25-pin varieties, both of which effectively function the same way. Serial ports are largely being eliminated in favor of much faster USB and FireWire connection standards. |
| Serial Presence Detect | An 8-pin serial EEPROM chip available on some SDRAM memory that keeps specific information about a DIMM's size, speed, voltage, drive strength, number of row and column addresses, DIMM manufacturer, and RAM manufacturer. If a motherboard supports SPD, it can set its BIOS automatically based on these settings to achieve maximum compatibility. |
| Server Farm | A group of servers usually located in a secure area, and sometimes collocated at an ISP. These servers all serve a single purpose (such as serving Web pages, for example) and have some sort of load balanced across them. If one server in the farm dies, business carries on as usual. If performance is slow, you add more servers. This term is popular when dealing with Web-based applications, where a group of webservers all serve up the same content or pull data from a database server or group of database servers. |
| Server Message Block | A client/server method of communication that allows a client to make requests for resources over a network. A server responds to these requests. SMB runs over most common network protocols, including NetBEUI, IPX/SPX, and TCP/IP. |
| Server Side Includes | A method of calling, or "including," code into a Web page. To utilize SSI your webserver must be set to check for and respond to these codes called in HTML pages. The SSI calls are embedded in HTML comments, so if they are called from a server that doesn't support SSI or is not actively looking for them, they are ignored. You can use SSI to easily include a particular bit of HTML code on a group of HTML pages. This can be used to create a single look and feel across multiple HTML pages. You can also use SSI to call CGI programs. |
| Service Advertising Protocol | This protocol is used on NetWare networks to advertise available network services. For example, a NetWare server uses SAP to let other computers know that it's offering up some shared files. |
| Service Level Agreement | A promise of maintaining a consistent level of data transfer over a network. Every ISP typically has an SLA that states the promise of data availability that the ISP will provide for its customer. Usually SLAs are only given to business customers that pay more for their connections than home users; thus business connections are typically more reliable, and also cost more. SLAs are very important for companies that can lose millions of dollars when their customers cannot access their webservers. |
| Service Protocol Identifier | A unique identifier that an ISDN provider's ISDN switch uses to identify ISDN clients. SPIDs are often similar in format to a phone number, but vary between ISDN providers. |
| Servlet | A program written for the Java Servlet API and run on a webserver. Servlets are a potentially more efficient replacement for CGI programs written in Java and run on the server, as opposed to running Java on the client. To run servlets a webserver must have the Java Servlet API installed. |
| SGRAM | This is actually a form of SDRAM with some additional features to speed up 3D graphics. It is used on some graphics cards. |
| Shading | This synonym for hacking up animals for human consumption determines how colors are used on each triangle displayed in a 3D image. Very complex images take a long time to render; less complex 3D images, such as those in a 3D game, can be rendered in real time. When they make computer animated movies or effects of very high quality, effects companies use many computers to render images. |
| Shadow Mask | A thin sheet of metal with small holes poked through it. It is used to focus the light from the electron beam on most CRT monitors. See also Slot Mask. |
| Shell | This most commonly refers to the various text-based user interface programs available for UNIX or Linux. The shell is the part of the OS that interacts with the user and accepts typed commands. Different shells have different functionality, so it is important to have the proper shell loaded or you may find yourself lost as things are displayed differently and familiar commands are not supported. |
| Shell Account | A term used with Internet dial-up accounts that can access a UNIX system at the command line instead of just connecting to the Internet through a browser. Shell accounts were at one time offered by many ISPs, but have fallen out of favor as the larger ISPs now cater mainly to volume users instead of more technical users. |
| Short Message Service | A method of sending text messages that are 160 characters in length or shorter over a mobile phone. More and more mobile phones are supporting the sending and receiving of SMS messages. |
| Shortcut | A pointer to an actual program or file, as opposed to a full copy of that file. Shortcuts can also point to other shortcuts, and are used mainly because they take up less space. For example, in Windows you can place a shortcut to a 200 KB file on the desktop which will only take up 1 KB, as opposed to copying the entire file to the desktop, which would take up the full 200 KB. Another benefit is that if you need to update a file that has several shortcuts, you don't have to update several copies of it, just one. |
| Silicon | Not to be confused with "silicone," silicon is the main component of computer chips. It is an element commonly associated with glass. It is called silica when bonded with oxygen. Sand and quartz is a form of silica. |
| Silicon on Insulator | The practice of placing a thin layer of silicon on top of an insulating material in order to speed up the performance of a microprocessor by reducing the capacitance of the transistors and making them operate faster. |
| SIMD | A processor instruction that can perform operations across multiple data instructions. So, instead of saying "Add A,B" several times to add two groups of numbers, you may say "Add Row A, Row B" or something to that effect. Instructions of this nature are often associated with 3D graphics and multimedia. |
| SIMM | A small memory card used with Fast Page Mode DRAM and EDO DRAM standards. SIMMs are 8-bit memory modules that had to be added in groups of four for processors with 32-bit memory interfaces. SIMMs were replaced by DIMMs. |
| Simple Mail Transfer Protocol | The Internet standard for transferring e-mail. It uses TCP/IP port 25 and allows for file attachments. |
| Simple Network Management Protocol | A protocol used to manage network devices, usually hubs and routers. It operates over UDP, which is part of TCP/IP. Devices that support SNMP send messages to a management console. The management console then stores these messages in the MIB (Management Information Base). SNMP is often used to get traffic reports on hubs and check network utilization on various devices. |
| Simple Screen Management Protocol | A communications protocol for text-based terminals. |
| Single Edge Contact Cartridge | The SECC is a processor cartridge designed to hold Intel's Pentium II and some external cache. It then plugs into a motherboard that supports Slot 1. This was replaced by SECC2 in some Pentium II 450s and all Pentium IIIs. SECC2 is a smaller and more cooling-efficient design, allowing the processor to come in direct contact with a heatsink. |
| Single In-Line Memory Module | A small memory card used with Fast Page Mode DRAM and EDO DRAM standards. SIMMs are 8-bit memory modules that had to be added in groups of four for processors with 32-bit memory interfaces. SIMMs were replaced by DIMMs. |
| Single Instruction Multiple Data | A processor instruction that can perform operations across multiple data instructions. So, instead of saying "Add A,B" several times to add two groups of numbers, you may say "Add Row A, Row B" or something to that effect. Instructions of this nature are often associated with 3D graphics and multimedia. |
| Single Large Expensive Drive | Back in the early days of hard disks you had two choices: SLED or RAID. SLED systems used a single high capacity hard drive to store lots of data. The drive may have contained a platter that was three feet (one meter) across, and it was very expensive. RAID allowed users to link a bunch of smaller, cheaper hard drives together for redundancy and to save the cost of a SLED. As costs and physical sizes of high capacity hard drives decreased and physical drive sizes were standardized, the term SLED has lost its meaning. |
| Single-Ended SCSI | The standard form of SCSI. It implies that there is a wire for each SCSI signal sent. |
| Site License | Usually software manufacturers will sell their software based on the amount of users using the software. As the amount of users increases and prices get higher, software manufacturers will sometimes sell a site license that entitles an entire site to use as many licenses as it needs to at a particular location for a single price. This makes management of a large amount of licenses unnecessary and simplifies things for the customer and the software vendor. For example, one company may have a 1-user, 5-user, 10-user, 25-user, and finally a site-license version of its software. The site license will be the most expensive, but may be more economical if you have a large amount of users. |
| Skin | A graphic or graphic scheme that is placed over a 2D or 3D object. For 3D games such as Quake, you can wrap a 2D graphic skin around your 3D character to change its appearance. Another skin example would be a Web browser that customizes the way it looks. Most programs that allow the use of skins have publicly available standards for creating new skins. |
| SKU | A number associated with a particular product, often represented by a barcode. The SKU is used to track inventory and may or may not be shown to customers when shopping on the Web. |
| SLA | A promise of maintaining a consistent level of data transfer over a network. Every ISP typically has an SLA that states the promise of data availability that the ISP will provide for its customer. Usually SLAs are only given to business customers that pay more for their connections than home users; thus business connections are typically more reliable, and also cost more. SLAs are very important for companies that can lose millions of dollars when their customers cannot access their webservers. |
| Slashdot Effect | This describes what happens when a highly trafficked website links to a smaller website, and sends such a large amount of traffic towards the smaller website over a short period of time that the website becomes inaccessible, or at least very slow. The phrase was first used to describe the effect that Slashdot.org had when it linked to small sites in its daily news items. |
| Slave | This usually refers to an IDE setting on a hard drive or other IDE device. When two devices are used on a single IDE channel, one is set to master and the other to slave. See also master. |
| SLED | Back in the early days of hard disks you had two choices: SLED or RAID. SLED systems used a single high capacity hard drive to store lots of data. The drive may have contained a platter that was three feet (one meter) across, and it was very expensive. RAID allowed users to link a bunch of smaller, cheaper hard drives together for redundancy and to save the cost of a SLED. As costs and physical sizes of high capacity hard drives decreased and physical drive sizes were standardized, the term SLED has lost its meaning. |
| Sleep mode | The placement of a computing device into an inoperable mode, where less power is consumed by shutting down unnecessary devices, but leaving all data in RAM. Typically you return from sleep mode by using the keyboard or mouse, and devices are switched back on. Sleep mode in its early incarnations was very problematic in some PCs, and would often crash programs and operating systems that were not completely compatible with the sleep mode in the PC's BIOS. |
| Slocket | A circuit board that most commonly accepts a Socket 370 and/or FC-PGA microprocessor, and in turn plugs into a Slot 1 motherboard connection. Thus, socketed microprocessors can be made to work on motherboards with only slot connections. |
| Slocket2 | Similar to the Slocket1, or just plain Slocket, this is an adapter so that Socket 370/PPGA and also FC-PGA processors can fit into Slot 1 motherboards. Slocket2 adapters add the ability for FC-PGA chips to work in Slot 1 motherboards. Intel made changes to the Socket 370 spec to make the FC-PGA spec, so that normal (non-Slocket2) Slocket adapters do not work with FC-PGA chips. |
| Slot 1 | A cartridge slot found on motherboards that accepts an SECC or SECC2 cartridge. It works with Intel's Pentium II and III chips, and some Celerons were also shipped that use slot 1. Most Celerons used Socket 370 instead. |
| Slot 2 | An Intel-designed specification that accepts a slot 2 cartridge. Intel ships its Xeon family of processors in a slot 2 cartridge. Slot 2 motherboards always accept at least two slot 2 cartridges. If you use only one processor in a slot 2 motherboard, you must put a termination card in the second slot. |
| Slot A | This slot developed by AMD is mechanically compatible with Intel's Slot 1, but not electrically compatible. This slot uses the Alpha chip's EV-6 memory bus, capable of transferring data at speeds at and over 200MHz. |
| Slot B | This slot developed by AMD is similar to Intel's Slot 2. It is mechanically compatible, but not electrically compatible. Just as Intel uses Slot 2 for its higher-end Xeon processors, AMD designed Slot B for K7 processors with high speed L2 caches for use in servers and workstations. |
| Slot Mask | This form of mask is similar to a shadow mask, but instead of a sheet of metal with holes poked into it it is a series of fine, vertically-aligned metal wires. |
| Slotket | A circuit board that most commonly accepts a Socket 370 and/or FC-PGA microprocessor, and in turn plugs into a Slot 1 motherboard connection. Thus, socketed microprocessors can be made to work on motherboards with only slot connections. |
| Slotket II | Similar to the Slotket1, or just plain Slotket, this is an adapter so that Socket 370/PPGA and also FC-PGA processors can fit into Slot 1 motherboards. Slocket2 adapters add the ability for FC-PGA chips to work in Slot 1 motherboards. Intel made changes to the Socket 370 spec to make the FC-PGA spec, so that normal (non-Slotket2) Slotket adapters do not work with FC-PGA chips. |
| SLS | One of the first Linux distributions, originally shipped on a number of floppies, that eventually became the Slackware distribution. |
| Small Computer Systems Interface | Pronounced "skuzzy," this is a standard data pathway used mostly for hard drives and CD-ROM drives; but it was also a common interface for scanners and even printers at one point. It is the fastest (and the most flexible) method of interfacing with hard drives. It comes in numerous varieties, and is mainly used in servers and high-end workstations. SCSI drives are much more expensive than IDE drives, but SCSI drives can have features, like 15,000 RPM spin speeds and 5-year warranties, that IDE drives currently do not. |
| Small Outline DIMM | A small form factor DIMM that is designed for use in laptops, graphics cards, and other devices that require a smaller than normal DIMM. The SO-DIMM allowed for an easily interchangeable SDRAM module for small form factor devices, replacing numerous proprietary laptop memory standards. |
| Small Scale Integration | Chips containing tens of transistors, but not hundreds. Today that's a very simple chip. See also VLSI, LSI, and MSI. |
| Smalltalk | An early object-oriented programming language developed in 1972 by the Software Concepts Group (led by Alan Kay) for the Xerox PARC project. It added onto the Simula-67 programming language and is still in use today by some. |
| SMART | This technology reports on a variety of hard drive attributes. You need a compliant BIOS and SCSI and/or IDE controller, a hard drive that supports SMART, and some sort of software package that reports on these conditions. Once you have that you should be able to receive system warnings about your hard drive. Many hard drive manufacturers have added onto the SMART technology or changed it around so that it has proprietary features for their drives. The good news about SMART is that having SMART is much better than not having it, and you can be warned of hard drive failure before it happens and backup your drive while it still works. Thus, your data is safer with SMART around. |
| SmartMedia | A type of Flash memory card that is roughly one-third the size of a PC Card (PCMCIA card) and less than 1 mm thick. It is used to store data from and exchange data among PDAs, digital cameras, and other devices. SmartMedia has largely given way to the even smaller MMC MultiMedia Card standard. |
| SMB | A client/server method of communication that allows a client to make requests for resources over a network. A server responds to these requests. SMB runs over most common network protocols, including NetBEUI, IPX/SPX, and TCP/IP. SMB |
| SMP | A technology where a computer uses multiple processors to process different instructions at the same time, in separate processing units. It is a form of parallel computing. |
| SMS | A method of sending text messages that are 160 characters in length or shorter over a mobile phone. More and more mobile phones are supporting the sending and receiving of SMS messages. |
| Smurf Attack | A network-based attack where the attacker(s) send out false ICMP echo requests that appear to originate from the IP address of the machine or network under attack. This type of attack can be used to flood a network or device with "responses" to the false ICMP requests. |
| SNA | An IBM architecture for enterprise computing systems. IBM has created a complete suite of programs to work on its proprietary hardware for enterprise computing. |
| Snail Mail | This simply refers to physical mail that travels via postal service as opposed to e-mail. The slow-moving snail is a reference to the relative speed of physical mail vs. the seemingly instantaneous speed of electronic mail. |
| SO-DIMM | A small form factor DIMM that is designed for use in laptops, graphics cards, and other devices that require a smaller than normal DIMM. The SO-DIMM allowed for an easily interchangeable SDRAM module for small form factor devices, replacing numerous proprietary laptop memory standards. |
| Socket | Normally a socket is where your limbs are attached to, as in "I'm going to rip your arm out of the socket." In network speak a socket is composed of an IP address and a port number. For example, a socket could be "10.119.148.38 port 80." See also TCP/IP and ports. Another meaning of socket refers to the pin grid array interface between some CPUs and the things into which they plug. |
| Socket 3 | The PGA socket into which a 486 class chip plugs. |
| Socket 370 | The common name for Intel's PGA processor socket, called the PPGA form factor. Intel initially designed Socket 370 to work with Celeron processors because socket designs are cheaper than Intel's Slot 1 and the Celeron didn't use any L2 cache, which was external at the time and the main reason for a slot design. |
| Socket 4 | A comparably large socket that was used with the original Pentium 60 and 66 processors. This quickly gave way to the smaller and more widely used Socket 5. |
| Socket 5 | This socket was first used with the Pentium 90 processor. However, its electrical capacity proved limiting, and it was done away with in favor of Socket 7 starting with the Pentium 150. |
| Socket 7 | A PGA socket designed to accept an Intel P54c or P55c (Pentium class) chip, an AMD K5, K6, or K6-2 chip, or a Cyrix 6x86 or MII chip. Its memory bus is limited to a speed of 66MHz. Super 7 was the next generation of this Socket design that allowed for higher bus speeds. |
| Socket 8 | This PGA socket is designed to accept an Intel Pentium Pro chip. |
| SOCKS | A protocol for communication through a firewall or proxy server. The SOCKS protocol uses TCP/IP sockets for communication. SOCKS is supported by most browsers, and allows them to communicate through proxy servers and firewalls, assuming the user has proper privileges to do so. |
| Soft Copy | An electronic copy of a document, as opposed to a hard copy, or physical printout, of that document. |
| Soft Reset | The controlled shutdown and restart of a PDA or other device by means of using a mechanism supplied by the operating system or software that runs the device. |
| Softlanding Linux System | One of the first Linux distributions, originally shipped on a number of floppies, that eventually became the Slackware distribution. |
| Software | The programs that run on computer hardware. This can include operating systems, office suites, games, Web browsers, and more. Software runs on hardware. |
| Software Developer's Kit | A programming tool that is tailored towards a particular purpose. The kit includes a compiler, linker, and an editor. Most hardware manufacturers have SDKs available that work specifically with their hardware. For example, if you were writing a program to work with a SoundBlaster card, you'd want to get the SoundBlaster SDK from Creative Labs. |
| Software License | Most corporations need multiple copies of software, but do not need the media in which they come, either because they already have it or because they allow users to install software from a server on the network. Companies still need to purchase a copy for each user, however, so they need a way to prove they have actually purchased a copy of each. These companies purchase software licenses with no associated media. Such licenses are typically just sheets of paper that cost a lot of money, but allow you to legally use additional copies of the software. |
| SOHO | A class of equipment purchasers characterized by their requirements for low-cost but functional computers, fax machines, printers, and other office equipment. Most computer makers target this market as a separate market segment between that of standard consumers and small businesses. |
| SOI | The practice of placing a thin layer of silicon on top of an insulating material in order to speed up the performance of a microprocessor by reducing the capacitance of the transistors and making them operate faster. |
| Solaris | A UNIX-based operating system developed by Sun Microsystems and used widely for enterprise-class servers. It is designed to work with Sun's own SPARC chips as well as Intel's x86 microprocessors. |
| Solid State Drive | This type of storage is basically a huge block of RAM chips that functions like a hard drive. Solid state drives are extremely expensive, but offer very high data speeds that are necessary in some applications. They can also be used as large caches on huge RAID subsystems, but due to the volatile nature of the DRAM used as storage solid state drives should be used carefully. |
| SONET | A fiber optic network in a ring topology, often used to carry voice signals or Internet traffic. One ring is described as hot, or carrying data. The other ring is the protect--or standby--ring that transmits data in the opposite direction in case of service degradation or a fiber cut. Typically, within 50 milliseconds of a failure SONET equipment on the edge of the failing segment attempts to construct a new ring using a combination of standby fiber and hot fiber--if any of it is working. |
| Sonictron | This is Viewsonic's answer to Sony's Trinitron. Like Trinitron, it uses an aperture grill, or slot mask, instead of a shadow mask. |
| Sound Card | A peripheral device in the form of a card used for producing sound and music. Although PCs come with a built-in speaker, it was originally tied to the CPU and did not do a good job of reproducing complex sounds. As for reproducing sound, the speaker takes most of the processor's power to produce only marginal sound, whereas a sound card does it effortlessly and creates a much better reproduction. Most motherboards today come with some kind of external sound chip built-in, just in case you want decent sound without attaching a separate sound card. |
| Sound Pressure Level | A measure in decibels of the sound power produced by an object. It is measured with a sound level meter. There are contests held to see what vehicle can produce the highest SPL through its sound system. |
| Source | The uncompiled code of a computer program. Before compiling you can look at the instructions and tell what the program does--if you are familiar with the programming language. After compiling, the source code is transformed into machine code that is much more low level and hard to follow, making optimizations and fixes almost impossible. Thus, some developers package the source code with their software so that if people want to improve it or fix it--or just see how it works-they can do that. |
| Source Code | The uncompiled code of a computer program. Before compiling you can look at the instructions and tell what the program does--if you are familiar with the programming language. After compiling, the source code is transformed into machine code that is much more low level and hard to follow, making optimizations and fixes almost impossible. Thus, some developers package the source code with their software so that if people want to improve it or fix it--or just see how it works-they can do that. |
| Southbridge | Part of a chipset in a PC that controls communications between among the PCI bus, IDE controller, BIOS, USB, power control, and PS/2 ports. See also northbridge. You must pair a northbridge and southbridge chip to create a full chipset. |
| Spatial Database | This is simply a database that contains geographical or "spatial" information. For example, you could have a database of population by county in the United States, or amount of sales by state, or amount of employees per site. |
| SPD | An 8-pin serial EEPROM chip available on some SDRAM memory that keeps specific information about a DIMM's size, speed, voltage, drive strength, number of row and column addresses, DIMM manufacturer, and RAM manufacturer. If a motherboard supports SPD, it can set its BIOS automatically based on these settings to achieve maximum compatibility. |
| Speaker Shielding | The ferro-magnetic shielding around the magnets of speakers that prevents interference with a CRT monitor and prevents damage to magnetic media such as floppies and hard drives. |
| Specular Highlights | This allows for the appearance of light reflecting off an object when represented on 3D computer graphics. White or light-colored pixels are blended into darker areas to provide these highlights. |
| SpeedStep | An Intel standard that allows its mobile processors to run at a lower MHz speed when used in a notebook that is not plugged into a power source. |
| SPID | A unique identifier that an ISDN provider's ISDN switch uses to identify ISDN clients. SPIDs are often similar in format to a phone number, but vary between ISDN providers. |
| Spindle | The centerpiece of a hard drive which holds one or more hard drive platters. Often the term spindle is used to differentiate hard drives from hard disk platters in discussion when referring to large RAID subsystems holding many hard drives, such as "We'll be using 50 spindles instead of 10 spindles in the new RAID box." Basically a spindle is seen as a limiting factor in performance; generally, more spindles in a system mean higher possible performance. |
| SPL | A measure in decibels of the sound power produced by an object. It is measured with a sound level meter. There are contests held to see what vehicle can produce the highest SPL through its sound system. |
| Spoof | A generic term for misleading a computer system into believing that you are not who you say you are. Most commonly, it refers to a TCP/IP trick that allows you to get around network security by impersonating a TCP/IP address inside of the network. |
| Spool | The intermediary device between a computer and a printer. In the old days, if you had no spooler your computer would wait as the printer slowly printed a document. You would send your print data to a spooler to accept the data and save it temporarily to hard disk or memory while it dealt with the slow printer for you. Nowadays print-server is a more current term for describing this type of device. Most modern operating systems contain spooler processes that take care of printing in the background, and you don't notice any delays anyway. Spool |
| Spooler | The intermediary device between a computer and a printer. In the old days, if you had no spooler your computer would wait as the printer slowly printed a document. You would send your print data to a spooler to accept the data and save it temporarily to hard disk or memory while it dealt with the slow printer for you. Nowadays print-server is a more current term for describing this type of device. Most modern operating systems contain spooler processes that take care of printing in the background, and you don't notice any delays anyway. |
| Spreadsheet | A type of computer program that displays a group of cells (a 2D graph pattern) and allows for easy mathematical operations and relationships among the cells. The first major spreadsheet was Lotus 1-2-3. Today's most popular spreadsheet is Microsoft Excel. |
| SQL | This is a means of managing data in a relational database. There is a SQL standard, and there are also many vendor-specific SQL packages which combine relational databases with tools SQL tools to manage them. Statements in SQL can be used to read or request data from a database, such as, "select * from geek," which would return an entire table of data from the table named "geek." Queries can also be much more complex such as, "select * from geek where name=sam" which would return records from the database where the field "name" was set to "sam." SQL statements can also be used to delete and update data. |
| SRAM | This type of memory is much more expensive and physically larger than DRAM, but is also much faster. SRAM typically has much lower latency than DRAM. |
| SS7 | A motherboard that is built on the Super 7 platform, which is an extension to the Socket 7 platform that accepts Super 7 microprocessors with bus speeds over 66MHz. |
| SSD | This type of storage is basically a huge block of RAM chips that functions like a hard drive. Solid state drives are extremely expensive, but offer very high data speeds that are necessary in some applications. They can also be used as large caches on huge RAID subsystems, but due to the volatile nature of the DRAM used as storage solid state drives should be used carefully. |
| SSE | The name for Intel's additions to the x86 instructions set, introduced in its Pentium III processor. The SSE extensions are similar to AMD's 3DNow! set of instructions. These extensions are a set of 70 instructions that perform SIMD operations. In addition, to support these instructions Pentium IIIs come with 8 128-bit registers dedicated to them. |
| SSI | see Small Scale Integration or Server Side Includes |
| SSMP | A communications protocol for text-based terminals. |
| Stack | A data construct that uses first-in, last-out (FILO). Think of a stack of pancakes. The first pancake cooked (first in) is put on a plate and then covered with other pancakes as they are done cooking. The original pancake is the last one that leaves the plate if you eat them one at a time. See also queue. |
| Standalone | A hardware device or piece of software that works with nothing else required. Examples include a hardware-based MP3 player, a RAID server that hooks up directly to the network with no PC required to run it, or an executable program with the proper libraries embedded. Standalone can have many contexts, but it always refers to the ability to function without requiring other components. |
| Standard Template Library | A C++ library first available in 1994. When compiling C++ programs, using the STL allows you to make use of general container classes and generic algorithms that can make development easier. To use STL you must use a C++ compiler that can handle templates. |
| Star topology | A network topology that has network hubs at the center, with all connected computers linked back to the hub by a single cable. Thus, if one cable goes down, the rest of the computers can still communicate. |
| Stateful Inspection | The ability of a firewall to retain "state" information about ongoing network sessions. When a packet goes out through a stateful firewall (TCP/UDP/ICMP) it will only permit expected return traffic that would normally be returned in response to that packet from the remote site. This prevents spoofed packet attacks and other nasty things. |
| Static IP Address | An IP address that does not change. Most IP addresses for client machines are handed out by a method such as a DHCP server that manages a range of IP addresses. Static IP addresses are typically reserved for servers or routers, but some companies still use them for all their PCs. Most IP addresses handed out by an ISP are not static, but you can find ISPs that offer static IP addresses. |
| Static Random Access Memory | This type of memory is much more expensive and physically larger than DRAM, but is also much faster. SRAM typically has much lower latency than DRAM. |
| Stepping | The version of a particular chip. Microprocessors typically have many different steppings where performance is increased or minor bugs are fixed. The steppings are usually not touted as a new release of the chip because chips are not as easily upgradeable as software. You would have to buy a whole new chip to upgrade it. |
| STL | A C++ library first available in 1994. When compiling C++ programs, using the STL allows you to make use of general container classes and generic algorithms that can make development easier. To use STL you must use a C++ compiler that can handle templates. |
| Stock Keeping Unit | A number associated with a particular product, often represented by a barcode. The SKU is used to track inventory and may or may not be shown to customers when shopping on the Web. |
| Storage Area Network | A network of connected storage devices typically on the same high speed connections as servers in an enterprise. Often the storage devices in a SAN are connected by fiber optic connections. |
| Storage Data Acceleration | This technology was introduced by Western Digital. The idea behind it is that slower drives such as CD and DVD drives would attach directly to larger, faster hard drives. There would be a 10-pin connector between the hard drive and the other peripheral, as opposed to the 40-pin IDE connector. A portion of the hard drive would be used as cache for the CD drive or other device. This was touted to speed up CD-ROM drives by 50%-300% depending on what operations are being performed. You would have had to buy specialized hard drives and CD drives to take advantage of this technology, but it flopped, so don't worry about it. |
| Streaming | This term is often used to describe technology that is capable of playing audio or video while it is still downloading. This saves you some waiting. Without streaming you'd have to wait until the entire file downloaded before viewing or listening, making Internet radio and video fairly useless. |
| Streaming SIMD Extensions | The name for Intel's additions to the x86 instructions set, introduced in its Pentium III processor. The SSE extensions are similar to AMD's 3DNow! set of instructions. These extensions are a set of 70 instructions that perform SIMD operations. In addition, to support these instructions Pentium IIIs come with 8 128-bit registers dedicated to them. |
| Structured Query Language | This is a means of managing data in a relational database. There is a SQL standard, and there are also many vendor-specific SQL packages which combine relational databases with tools SQL tools to manage them. Statements in SQL can be used to read or request data from a database, such as, "select * from geek," which would return an entire table of data from the table named "geek." Queries can also be much more complex such as, "select * from geek where name=sam" which would return records from the database where the field "name" was set to "sam." SQL statements can also be used to delete and update data. |
| Stub | A discontinuity in a SCSI bus. There are required lengths between stubs for the various SCSI standards. Each SCSI device counts as a stub. You can think of anything that's not a continuous SCSI cable as a stub. |
| Subnet | A term that refers to a group of TCP/IP addresses defined by a subnet mask. A subnet mask determines how many addresses are in the same subnet as a particular TCP/IP address. Addresses in your subnet are reachable without going through a router, and thus can be reached by broadcasts. To reach addresses outside of a particular subnet you must transmit through a router. This is all part of the TCP/IP protocol. |
| Subnet Mask | A TCP/IP number used to determine to which TCP/IP subnet a device belongs. Devices in the same subnet can be communicated with locally without going through a router. When a TCP/IP device tries to communicate with another device the bits of the TCP/IP destination address are "ANDed" with the subnet mask to determine whether the address is a local address (broadcastable) or must be reached through a router. A subnet mask of 255.255.255.0 used by a computer with a TCP/IP address of 10.10.10.1 would include the addresses 10.10.10.0 through 10.10.10.255 in the local network, basically telling the computer to try a router if it's transmitting to any other IP address. |
| Subroutine | A mini program that resides inside another program and is called within that program. Typically you put together a subroutine when you have to do similar repetitive tasks in different areas of your program and you don't want to code the same thing over and over again. |
| Super 7 | A specification designed by an alliance of non-Intel companies. The Super 7 architecture extends the socket 7 architecture to include support for an AGP graphics port and memory bus speeds of 100MHz and over. |
| Super Bypass | A means of reducing memory latency in the AMD 750 chipset, the first chipset designed to work with the AMD Athlon. It was implemented in all versions of the AMD 750, but did not function properly in early versions. AMD corrected this problem with a new revision of the AMD 750 chipset. It is possible to identify the Super Bypass-capable chipsets electronically or through software, but the enabling or disabling of Super Bypass is done automatically by the motherboard BIOS. |
| Super VGA | An extension to the original VGA standard which allows resolutions of 800x600. See also VGA. |
| Super Video CD | Backwards-compatible with VCD 1.1, 2.0, and 3.0, SVCD supports higher resolutions and 2.2Mbps variable bitrate (VBR) MPEG-2 video encoding, as well as MPEG-1 or MPEG-2 audio encoding. The resolution of SVCD video is 480x576 (PAL) and 480x480 (NTSC), up from VCD's 352x288 (PAL) resolution. SVCD supports 5.1 audio, but it is not Dolby 5.1. You must use a 2x or faster CD-ROM drive to read SVCDs, as opposed to 1x drives for VCD. Video quality is between VCD and DVD quality, and SVCDs are mainly found in Asia. |
| Super XGA | A display with 1280x1024 pixel resolution. |
| Super XGA+ | A display with 1400x1050 pixel resolution. It is a hybrid resolution between SXGA and UXGA found on some LCD screens in laptop PCs. |
| Super-Video | A video cabling standard that splits video information into two separate signals: one for brightness (luminance), and the other for color information (chrominance). In contrast to composite video, S-Video has a sharper picture. Nowadays, DVD players, some VCRs, and many high-end televisions support S-Video. S-Video is also supported by many electronic accessories, such as camcorders, computer video cards with TV functions, and even console games such as the Sony PlayStation. |
| Supercluster | A group of computers linked together via a high speed local network. The performance of such a supercluster compares with the performance of a supercomputer. |
| Supercomputer | A computer that is able to operate at a speed that places it at or near the top speed of currently produced computers. Most supercomputers cost millions of dollars, and the traditional model of using one large computer with proprietary hardware is being challenged by using a cluster of cheaper computers with more standard hardware. |
| Superscalar | A processor that is capable of executing more than one instruction during a processor cycle. Processors can do this by fetching multiple instructions in one cycle, deciding which instructions are independent of other instructions, and executing them. To do this the processor must have an instruction fetching unit that can fetch more than one instruction at a time, built-in logic to determine if instructions are independent, and multiple execution units to execute all the independent instructions. Instructions that depend on the results of the previous instruction obviously can't be executed simultaneously with the instructions on which they depend. This type of instruction slows down superscalar processors. If all instructions are of this type you get no benefit from the superscalar architecture. |
| Superstitial ad | A pop-up banner ad format created by Unicast. Superstitial ads load after a Web page is done loading, and pop up when a link is clicked. The pre-loading ensures that the ads don't slow the browsing experience. |
| Surge Protector | A specialized power outlet that uses capacitors to keep spikes in the power supply from damaging electronic devices. |
| SVCD | Backwards-compatible with VCD 1.1, 2.0, and 3.0, SVCD supports higher resolutions and 2.2Mbps variable bitrate (VBR) MPEG-2 video encoding, as well as MPEG-1 or MPEG-2 audio encoding. The resolution of SVCD video is 480x576 (PAL) and 480x480 (NTSC), up from VCD's 352x288 (PAL) resolution. SVCD supports 5.1 audio, but it is not Dolby 5.1. You must use a 2x or faster CD-ROM drive to read SVCDs, as opposed to 1x drives for VCD. Video quality is between VCD and DVD quality, and SVCDs are mainly found in Asia. |
| SVGA | An extension to the original VGA standard which allows resolutions of 800x600. See also VGA. |
| Swap file | An area of your hard drive that the operating system uses for additional memory when main memory is used up. Although slower, it is usually much more abundant. |
| SXGA | A display with 1280x1024 pixel resolution. |
| SXGA+ | A display with 1400x1050 pixel resolution. It is a hybrid resolution between SXGA and UXGA found on some LCD screens in laptop PCs. |
| Sybase | This company makes a SQL database product that competes with Oracle and Microsoft SQL Server. It's also the type of SQL upon which Microsoft based Microsoft SQL Server. |
| Symmetric Digital Subscriber Line | A form of digital subscriber line that has the same transmission speed upstream and downstream. It is most often used for business use, and is more expensive than the consumer version, ADSL. |
| Symmetric Multi Processing | A technology where a computer uses multiple processors to process different instructions at the same time, in separate processing units. It is a form of parallel computing. |
| Synchronize | The act of updating one set of data based on another similar set which may be more up to date. Synchronization can go one way or two ways, and follows a set of rules defined by the synchronization procedure. Synchronization is often used to update data such as address book data on PDAs, or e-mail on laptops that may not always be connected to the office e-mail server. |
| Synchronous | This refers to things that happen at the same time. More commonly, it is used in electronics to signify something occurring at the set pace of a clock, much like a metronome. It also can indicate that a DSL connection has the same upload and download speed. |
| Synchronous Dynamic Random Access Memory | This is like Fast Page mode DRAM, but arranged with a more efficient data pathway that allows for faster throughput. |
| Synchronous Graphics RAM | This is actually a form of SDRAM with some additional features to speed up 3D graphics. It is used on some graphics cards. |
| Synchronous Optical NETwork | A fiber optic network in a ring topology, often used to carry voice signals or Internet traffic. One ring is described as hot, or carrying data. The other ring is the protect--or standby--ring that transmits data in the opposite direction in case of service degradation or a fiber cut. Typically, within 50 milliseconds of a failure SONET equipment on the edge of the failing segment attempts to construct a new ring using a combination of standby fiber and hot fiber--if any of it is working. |
| System Bus | The path between a microprocessor and the chipset on the motherboard. This bus may or may not run at the same speed as the memory bus. |
| System Management Bus | A standard created by Intel in 1995. It is a two-wire specification that uses a connector the size of an RJ-45 plug and allows for communications between an external UPS or power device and a computer. SMB connections are found on many motherboards designed for servers and workstations. |
| System Software | The software that comes with a computer system, or more specifically, the operating system. |
| System Tray | The system tray is the location on the far right of the Windows 95/NT 4.0 (or newer version of Windows) taskbar. Within it always resides the clock, and often other user-installed programs that monitor the system or run constantly. If you double-click on items in the systray, you usually get some sort of window to open up and tell you about why the item is there and what you can do with it. |
| Systems Network Architecture | An IBM architecture for enterprise computing systems. IBM has created a complete suite of programs to work on its proprietary hardware for enterprise computing. |
| Systray | The system tray is the location on the far right of the Windows 95/NT 4.0 (or newer version of Windows) taskbar. Within it always resides the clock, and often other user-installed programs that monitor the system or run constantly. If you double-click on items in the systray, you usually get some sort of window to open up and tell you about why the item is there and what you can do with it. |
| T1 | Two pairs of copper wire that carry data at a rate of 1.544Mbps. T1 lines are used to carry 24 DS-0 signals. They can be used to carry 24 phone lines or an Internet connection capable of 1.544Mbps data transfer. See also fractional T1. |
| T2 | Four T1 lines which can carry 96 voice channels or up to 6.312Mbps worth of data. |
| T3 | 28 T1 lines together make up a T3, which can carry 672 separate voice channels or up to 44.736Mbps data throughput. |
| T4 | 6 T3 lines make up a T4, which carries data at 274Mbps. |
| T5 | 240 T1 lines, which can carry 5760 voice channels or up to 400.352Mbps worth of data. |
| Tab Delimited | A text file where data elements in the text file are separated by the tab character. |
| Tachometer | A gauge the measures how fast a motor is running in revolutions per minute. The gauge can represent the information in analog or digital, and is critical when driving performance vehicles. Without a tachometer you can judge the RPM speed of a motor by listening to how fast it sounds like it is running. |
| Tag Image File Format | A bitmap graphics file format. It was developed by Aldus in 1986 to provide a common format for scanners, and is mainly used for that purpose, desktop publishing, and as the data format for scanned faxes. |
| Tag RAM | A bank of SRAM that only holds addresses. Tag RAM is used to store addresses so that when the processor makes a call for memory it first checks to see if the data is in the cache by looking for the memory address in the tag RAM. If it's there, it gets the data from cache. If not, it gets the data from main memory. Tag RAM controls the amount of memory that can be cached. For example, the Tag RAM used with most Intel 430TX chipsets only allowed the first 64 MB of RAM to be cached. You could use more RAM in your machine but it won't be cached, and thus performance will be affected when memory over 64 MB is accessed. |
| TAO | A method of writing data to a CD-R or CD-RW disc on a track by track basis. Recording can be paused between writing tracks, unlike Disc at Once, which requires an uninterrupted full-disc recording. You can create unclosed CDs with TAO recording that you can write to again at a later time. |
| Tape | A storage medium that consists of a long band of magnetic material wound around a couple of reels. Tapes can hold a lot of information, but are typically slow to access different parts of the tape, and can be unreliable for long-term storage due to their magnetic nature. |
| Tape Archive | A UNIX/Linux command that was designed to allow the storage of data spread across files and directories to exist in a single tape volume. Another handy use is to squeeze a directory or group of files into a single file on a hard drive, and then compact it with a compression program such as gzip to save some space. Simple usage includes "tar cvf" (cvf = create verbose-mode file), or "tar xvf" (x = extract) to extract a .tar file back to its original contents. |
| Tape Drive | A device that can store data on a tape. The advantage of storing data on a tape is that a tape can hold large amounts of data in a small and inexpensive package. On the downside, a tape cannot store the data indefinitely, and it is expensive and slower compared to a hard drive. But tapes themselves are cheaper, and are more easy to move around than hard drives. |
| TAPI | An API for using telephony functions in Windows. For example, you can include TAPI instructions in your program that can dial numbers, receive calls, and interpret touch-tones. |
| Tar | A UNIX/Linux command that was designed to allow the storage of data spread across files and directories to exist in a single tape volume. Another handy use is to squeeze a directory or group of files into a single file on a hard drive, and then compact it with a compression program such as gzip to save some space. Simple usage includes "tar cvf" (cvf = create verbose-mode file), or "tar xvf" (x = extract) to extract a .tar file back to its original contents. |
| Taskbar | The space that normally sits at the bottom of the Windows 95/98/NT4/2000/XP interface. It displays the list of running programs so that you can easily switch among programs even when you have a maximized window taking up the entire screen otherwise. It can be moved to either side or the top of the screen. |
| TCO | This phrase was coined by the creators of the Network Computer (NC) to describe the benefits of using a system that is more mainframe and less client/server. Their logic states that NCs, although they may cost the same up front as cheap PCs, have a lower TCO than a network built on PCs. |
| TCP | The part of the TCP/IP suite of protocols that is responsible for forming data connections between nodes that are reliable, as opposed to UDP, or IP, which TCP is based on, and which is by default connectionless and potentially unreliable. |
| TCP/IP | The TCP/IP suite first saw use on the original Department of Defense Internet in 1983. Its first implementation was amazingly successful, and it is still THE protocol of the Internet. In fact, it has grown even more, and is being used in private networks around the world. TCP/IP is a suite of communications protocols that allows communication between groups of dissimilar computer systems from a variety of vendors. It scales better than NetBEUI because NetBEUI is not routable, and beat out IPX/SPX as it was easier to route than that once-dominant protocol. |
| Technographer | This person types into a computer exactly what a person speaking at a meeting requests of them. The output is displayed on a screen for all to see. The important thing here is that anyone can speak and ask the technographer to type in what he or she wants. The technographer doesn't type everything that is said, just what the speaker wants the technographer to type. What is typed cannot be changed by anyone but the speaker, even if it makes everyone else angry and has nothing to do with the meeting. Do you see an opportunity for fun here? |
| Telecom | Refers to the industry and hardware involved with telephones and the transmission of voice data. |
| Telecommunications | Refers to the industry and hardware involved with telephones and the transmission of voice data. |
| Telephony | The science of audio communication through electric devices. It commonly refers to the many pieces of software that will make your $2,000 computer act like a $20 telephone. Of course, you can make this work for you with CTI. With CTI, you can make a $2,000 computer act like a $20,000 a year employee who works 24 hours a day. |
| Telephony API | An API for using telephony functions in Windows. For example, you can include TAPI instructions in your program that can dial numbers, receive calls, and interpret touch-tones. |
| TeleTypewriter | This term refers to a means of sending data one character at a time. The TTY interface is often used by dumb terminals to communicate with mainframes. |
| Telnet | An old protocol for remotely logging in to another computer. It is one of the basic utilities for TCP/IP, and is available in Windows, UNIX, and Linux at the command line. If you are using telnet, you should consider using SSH instead, as it has the same functionality but encrypts the data that is sent back and forth. |
| Terabit | Approximately 1 trillion bits. More exactly, it is 2^40, or 1,099,511,627,776, bits. |
| Terabyte | One trillion bytes, or one thousand gigabytes. |
| TeraFlop | The ability of a system to compute one trillion floating point operations in one second. |
| Terminate and Stay Resident | A program that runs, loads into memory, and stays out of view until you call on it. TSRs were commonly used in DOS, and are not necessary in modern operating systems. |
| Termination | Because of the amount of signals that SCSI format sends through small wiring, termination is required. The termination is accomplished by using resistors across certain signal wires. If the chain were not terminated, the signals would bounce off the end of the chain and cause interference with real signals. |
| Texel | The smallest element of a textured 3D surface. Pixels make up 2D surfaces, but texels make up the surfaces that cover textured 3D objects. Higher texel fill-rates generally imply better performance in 3D graphics accelerators. |
| Text Editor | A class of computer programs that allows the opening, changing, and saving of text files. Text editors can be used to edit HTML files, and any file that is not binary in nature. Text editors are not good for working with graphics files or proprietary formats such as Word documents that contain formatting information that is not translated properly to plain text. Text editors differ from word processors because no formatting data (such as font type, font size, etc.) is added when a file is saved in a text editor. |
| Texture Element | The smallest element of a textured 3D surface. Pixels make up 2D surfaces, but texels make up the surfaces that cover textured 3D objects. Higher texel fill-rates generally imply better performance in 3D graphics accelerators. |
| Texture Mapping | This technique pastes saved images, to be used as textures, onto triangle surfaces to improve realism. For example, you could take a picture of a grassy field, code the program to use this picture to fill in your triangles on the floor, and you get what looks like grass on which you can walk. |
| Tflop | The ability of a system to compute one trillion floating point operations in one second. |
| TFT | A synonym for the Active Matrix display. You'll often see screens referred to as "TFT-Active Matrix," or just "TFT" if the manufacturer is low on space. |
| TFTP | A network transfer protocol that allows you to connect to a device and download code onto it. For example, it can be used to shove boot code onto a diskless workstation, or connect and download firmware updates to networking devices. |
| Thermal Compound | A paste that is applied between a microprocessor and heatsink. This paste fills in any tiny gaps that may be present on the visibly flat surfaces of the microprocessor package and heatsink. Without thermal compound cooling may be less efficient, as the heatsink and microprocessor package may have air gaps between them. Thermal compound has much more efficient heat exchange properties than air. |
| Thermal Paper | A type of paper that displays a mark on it when heat is applied. Some older printers and fax machines used thermal paper, as it allowed for a very cheap printing mechanism. |
| Thermal Paste | Synonymous with thermal compound. A paste that is applied between a microprocessor and heatsink. This paste fills in any tiny gaps that may be present on the visibly flat surfaces of the microprocessor package and heatsink. Without thermal compound cooling may be less efficient, as the heatsink and microprocessor package may have air gaps between them. Thermal compound has much more efficient heat exchange properties than air. |
| Thermal Printer | A printer that produces characters by applying heat to special heat-sensitive thermal paper. |
| Thermal Tape | Like thermal compound, thermal tape fits between a microprocessor package and heatsink and gives greater heat conductivity than air. Thermal tape is typically less efficient than thermal compound. |
| ThickNet | The type of cabling on which 10Base5 Ethernet runs. It can transfer data at up to 10Mbps using the 10Base5 Ethernet standard. It is thicker than 10Base2 cabling, and thus the name. |
| Thin Client | A thin client is similar to a dumb terminal in that it gets all of its information from the network. Some thin clients have their own memory, but lack a hard drive. They're basically stripped down computers that are supposed to lower the total cost of owning a computer. These computers are generally used in business or commercial applications. |
| Thin Film Transistor | A synonym for the Active Matrix display. You'll often see screens referred to as "TFT-Active Matrix," or just "TFT" if the manufacturer is low on space. |
| ThinNet | This refers to the type of cabling on which 10Base2 Ethernet runs. It can transfer data at up to 10Mbps using the 10Base2 Ethernet standard. It is thinner than 10Base5 cabling. ThinNet |
| Thrash | The action of a computer component, usually a hard drive, that is doing a lot of work but not getting much done. Hard drive thrashing is often due to running out of physical memory, forcing your system to use the swap file as additional memory; but it can also be due to a hard drive that is badly fragmented. Also, if you're dancing around to Rob Zombie, you're probably thrashing! |
| Thread | Part of a program that runs independently or along with other threads to accomplish a task. To run multiple threads you must be running on an operating system such as UNIX or Windows NT/2000/XP that supports multiple threads. The performance benefit of allowing multiple threads to run at the same time is realized mainly on multi-processing systems. Different threads run on different processors, so they can run simultaneously. |
| Throughput | Any measure of the speed of data transmission. |
| Thumb | A small representation of a larger graphic. Detail is lost in the representation, but you get an idea of the content of the graphic. Thumbnails are often used on the Internet to display several graphics at once, or in imaging software so that you can sort through images more easily. |
| Thumbnail | A small representation of a larger graphic. Detail is lost in the representation, but you get an idea of the content of the graphic. Thumbnails are often used on the Internet to display several graphics at once, or in imaging software so that you can sort through images more easily. |
| Tier 1 | An ISP that has its own worldwide Internet backbone |
| TIFF | A bitmap graphics file format. It was developed by Aldus in 1986 to provide a common format for scanners, and is mainly used for that purpose, desktop publishing, and as the data format for scanned faxes. |
| Time to live | The maximum amount of time that a data packet can travel on a network before being discarded and assumed to be lost. If you are using PING and getting high packet loss, try setting the TTL higher, or better yet fix your network. |
| Title Bar | The top portion of a window in a GUI that contains the title of the window. |
| Token Ring | A network topology pioneered by IBM and eventually made into the IEEE 802.5 standard. The original version transmitted data at 4Mbits/second, and it was updated to transmit at 16Mbit/second. Token ring networks are wired in a ring topology, and nodes on the network pass a token around. Whichever node has the token is allowed to use the network. |
| Toner | Basically this is ink in dust form. It is specially formulated to be sticky and to melt at a couple hundred degrees so that it bonds with paper when used in a laser printer or copier. |
| Toner Cartridge | When referring to laser printers (or copiers or fax machines) this is a cartridge that contains toner and the electrostatic drum used to transfer that toner. |
| Toolbar | A common user interface term that refers to any rectangular bar of buttons or icons with a set of related functions. For example, most browsers use a toolbar for navigating forward or backwards through pages. You can often customize toolbars and add more functionality to them. |
| Toolkit Without An Interesting Name | A set of operations that allow scanners to have a standard interface to software. This allows the use of your favorite graphics package with your favorite scanner without worrying if one will support the other. As long as both are TWAIN-complaint they will work together. Check out www.twain.org for much more information. |
| Topology | The general structure of a network. Some examples are star and ring topology. |
| Torx | A type of indent in a screw head that looks like a 6-pointed star. Compaq used torx screws for all of its computer equipment at one point. Torx screws are also used in some automotive applications for body trim that should not be easily removed, such as to hold in the headlights on a '79 Chevy Malibu. Because a Torx driver is rarer than a Phillips-head or flat-head screwdriver, Torx screws are used as a simple security method. |
| Total Cost of Ownership | This phrase was coined by the creators of the Network Computer (NC) to describe the benefits of using a system that is more mainframe and less client/server. Their logic states that NCs, although they may cost the same up front as cheap PCs, have a lower TCO than a network built on PCs. |
| Touchpad | A pad that is electrically sensitive to touch, often used as the pointing device in laptops. You can also tap on it for clicks, but some people find that annoying if they bump the pad while typing. |
| Tower Case | An improvement to the standard desktop case, a tower case is flipped 90 degrees to accommodate more inside and to make it more convenient by allowing the case to be placed on the floor instead of on the desk. |
| TPC | A group that defines industry standard benchmarks that compare the ability of hardware and software platforms to perform database transactions. The performance is measured in terms of raw performance (higher is better) and US dollar cost per thousand transactions (tpmC--lower is better). |
| TPM | The amount of database transactions a server can do in a minute's time. This method of measurement is often used to compare high-powered database servers with multiple processors. Often the ratio of money per transactions is used to show the cost-effectiveness of a particular server. |
| Traceroute | A command that displays PING results for each router encountered between a source and a destination TCP/IP address. Traceroute is useful for getting some information along the entire path between two TCP/IP addresses. Firewalls or other security measures that block PING traffic also block traceroutes. The command itself is typed "tracert" on the command line of most operating systems. |
| Tracert | A command that displays PING results for each router encountered between a source and a destination TCP/IP address. Traceroute is useful for getting some information along the entire path between two TCP/IP addresses. Firewalls or other security measures that block PING traffic also block traceroutes. The command itself is typed "tracert" on the command line of most operating systems. |
| Track | One of the concentric circles of data on disk media such as hard drives, CD-ROM discs, DVD discs, and floppy disks. |
| Track at Once | A method of writing data to a CD-R or CD-RW disc on a track by track basis. Recording can be paused between writing tracks, unlike Disc at Once, which requires an uninterrupted full-disc recording. You can create unclosed CDs with TAO recording that you can write to again at a later time. |
| Trackball | This is basically a mouse turned upside down. Instead of moving the whole pointing device, you simply move the ball on top. It was first seen in arcade games such as Missile Command and Centipede, but is now used to replace mice where space is limited. |
| Transaction Processing Performance Council | A group that defines industry standard benchmarks that compare the ability of hardware and software platforms to perform database transactions. The performance is measured in terms of raw performance (higher is better) and US dollar cost per thousand transactions (tpmC--lower is better). |
| Transactions Per Minute | The amount of database transactions a server can do in a minute's time. This method of measurement is often used to compare high-powered database servers with multiple processors. Often the ratio of money per transactions is used to show the cost-effectiveness of a particular server. |
| Transceiver | A device that translates between different network cables but maintains the same network topology. Thus, a transceiver could allow an AUI (Thick-Ethernet) NIC to work with a Cat5 network cable. |
| Transfer rate | The rate at which data is transferred in some amount of bits per second. |
| Transistor | An electronic device that acts like an electrically activated switch but has no moving parts, so it can switch millions of times per second. |
| Transistor Transistor Logic | A specific method of wiring a digital circuit using bipolar transistors. |
| Transmission | The act of uploading or sending data. Often the term "TX" is used on indicator lights on modems or network cards to indicate that data is flowing out of the device. |
| Transmission Control Protocol | The part of the TCP/IP suite of protocols that is responsible for forming data connections between nodes that are reliable, as opposed to UDP, or IP, which TCP is based on, and which is by default connectionless and potentially unreliable. |
| Transmission Control Protocol/Internet Protocol | The TCP/IP suite first saw use on the original Department of Defense Internet in 1983. Its first implementation was amazingly successful, and it is still THE protocol of the Internet. In fact, it has grown even more, and is being used in private networks around the world. TCP/IP is a suite of communications protocols that allows communication between groups of dissimilar computer systems from a variety of vendors. It scales better than NetBEUI because NetBEUI is not routable, and beat out IPX/SPX as it was easier to route than that once-dominant protocol. |
| Trapezoidal Control | A control on better CRT monitors that allows you to adjust the angles of the borders of the screen. |
| Tree | A means of organizing data that starts with a single node, or data element, that has any number of child elements. Each of these child elements or nodes can also have its own child elements. Trees are an important part of understanding programming and data structures. |
| Trilinear Filtering | Like Bilinear Filtering, this is used to smooth flat surfaces by averaging the colors of adjacent pixels, which blurs them and removes blockiness when examined closely. |
| Trinitron | A technology developed by Sony to enhance the clarity of graphics on its monitors. These screens were vertically flat and made the pixels appear more square and uniform. |
| Triple DES Encryption | A form of DES encryption that uses three separate 56-bit keys to encrypt and decrypt messages. This basically compounds the number of possible key combinations (72 quadrillion) three times, and makes it even harder to crack an encrypted message. |
| Trivial File Transfer Protocol | A network transfer protocol that allows you to connect to a device and download code onto it. For example, it can be used to shove boot code onto a diskless workstation, or connect and download firmware updates to networking devices. |
| Trojan Horse | A computer program that appears to be something useful, but then does something malicious to your computer. This could range from destroying data to laying dormant and someday hijacking your computer to be used as part of a Denial of Service attack. Anti-virus programs will protect you from known Trojan horses, but strictly speaking Trojan horses are unlike viruses because they do not replicate. However, combination virus/Trojans can replicate. |
| TRS cable | An analog cable used to connect audio devices. It typically comes in 1/4" and 1/8" diameters. It is balanced, as opposed to the unbalanced signals of RCA cables. |
| True Color | The name given to 32-bit, 16.7 million color representation. |
| True Parity | This term has come about with the advent of logical parity memory. It simply means that the parity memory actually does something useful instead of just issuing positives over and over. |
| TrueType | This is a font standard developed by Apple and used in Mac OS version 7. Later, Apple licensed the technology to Microsoft, which used it in Windows 3.1 and continues to use it today. However, Apple and Microsoft TrueType fonts are not compatible. |
| Truth table | A boolean table that describes the way that a circuit reacts to input values by showing a complete set of possible input values with corresponding outputs. |
| TSR | A program that runs, loads into memory, and stays out of view until you call on it. TSRs were commonly used in DOS, and are not necessary in modern operating systems. |
| TTL | see Time To Live or Transistor Transistor Logic |
| TTY | This term refers to a means of sending data one character at a time. The TTY interface is often used by dumb terminals to communicate with mainframes. |
| Tuple | Pronounced "en-too-pull." This is a mathematical term for a finite sequence of n terms. For example, the set {1, 2, 3, 4} is a four-tuple. The set {Frank, Jane, Ed} is a three-tuple. Any time there is a list of n things in a certain order, you can think of it as an n-tuple. |
| Turbo-Pascal | Borland's version of the Pascal programming language. |
| Turnkey | This usually refers to a server or a complex system that can basically be shipped from the manufacturer, turned on, and work right away. Many VARs pride themselves on providing turnkey servers on which their customers don't need to do any configuration. If you think of it in terms of an engine, a turnkey engine comes with all the parts and can be tossed into a car and work immediately. An engine that isn't turnkey will need additional parts and integration before it will run. |
| TWAIN | A set of operations that allow scanners to have a standard interface to software. This allows the use of your favorite graphics package with your favorite scanner without worrying if one will support the other. As long as both are TWAIN-complaint they will work together. Check out www.twain.org for much more information. |
| UART | A chip that standardized serial communications. Its function is to change a byte into a standard sequence of electrical impulses. |
| UDF | see Universal Disk Format or Universal Data Format |
| UDMA | short for Ultra DMA |
| UDP | Part of the TCP/IP suite of protocols. UDP is the part of the TCP/IP suite used by applications to transfer datagrams. It is also the part of TCP/IP responsible for port addresses. UDP got the short end of the stick in some ways in that its name isn't included in TCP/IP, but would you really want to call it TCP/UDP/IP? |
| ULSI | A microchip with over one million transistors. Most popular chips today fit this description. Maybe in 10 years we will have the SDULSI, for Super-Duper Ultra Large Scale Integration. For now this is at the top of the heap. See also VLSI, LSI, MSI, and SSI. |
| Ultra 160M | A form of SCSI that supercedes Ultra2 SCSI. It runs at up to 160 megabytes per second and uses 80-pin connections over copper wires. |
| Ultra 320M | A form of SCSI that doubles the potential performance of Ultra 160M SCSI and offers throughput of up to 320 megabytes per second per channel. |
| Ultra ATA/100 | Another extension to the ATA interface that adds a 50% increase in top speed over ATA/66, getting to 100MB/second, up from 66MB/second. This standard also adds some additional error-checking not found in earlier ATA standards. Like Ultra ATA/66, ATA/100 requires an 80-conductor cable to work at full speed. |
| Ultra ATA/133 | This refers to what is most probably the final extension to the parallel ATA connection standard. The proposal was created by Maxtor, and allows a top data transfer rate of 133 megabytes per second. Intel didn't support this standard in its chipsets, instead opting to wait for Serial ATA. See Serial ATA for further details. |
| Ultra ATA/33 | An extension to the ATA interface (IDE) that effectively doubles the top data transfer speed of IDE from 16.6MBytes/second up to 33 MBytes/second. Also known as Ultra-IDE. |
| Ultra ATA/66 | An extension to the ATA interface (IDE) proposed by Quantum that effectively doubles the data transfer speed of the Ultra ATA/33 interface to 66MBps. To achieve the increase in speed you must use a special 80-conductor cable with 40 data lines and 40 ground lines to keep the signal stable. |
| Ultra DMA | An extension to the ATA interface (IDE) that effectively doubles the top data transfer speed of IDE from 16.6MBytes/second up to 33 MBytes/second. Also known as Ultra-IDE. |
| Ultra Large Scale Integration | A microchip with over one million transistors. Most popular chips today fit this description. Maybe in 10 years we will have the SDULSI, for Super-Duper Ultra Large Scale Integration. For now this is at the top of the heap. See also VLSI, LSI, MSI, and SSI. |
| Ultra SATA | A specification for consumer hard drive connections that boosts the data transfer rate up to 150MB/second. In addition, it changes IDE/ATA from a parallel interface requiring 40 separate wires to connect components to a serial interface requiring only 6 wires. 2x and 4x versions of Serial ATA double and quadruple the speed of Serial ATA. |
| Ultra SCSI | This is SCSI that communicates twice as fast as standard SCSI-2. Normal Ultra-SCSI transfers data at 20MBps, and Wide Ultra-SCSI transfers data at 40MBps. Similar to Ultra-IDE, Ultra-SCSI works its magic by transferring data on the up AND the down stroke of a clock cycle, doubling throughput. |
| Ultra XGA | A display with 1600x1200 pixel resolution. |
| Ultra2 SCSI (LVD) | This standard doubles the maximum transmission speed of Ultra SCSI. Almost all devices made to this standard support the 80MBps transfer rate of Ultra2 Wide SCSI. See also LVD. |
| Ultra3 SCSI | Ultra3 SCSI doubles the maximum transfer rate of Ultra2 SCSI up to 160MBps. This is synonymous with 160M SCSI. |
| Ultraviolet | A spectrum of light with wavelengths from about four nanometers to 380 nanometers. Light below 4 nm is in the x-ray spectrum, and just above 380 nm is visible violet light, moving through the color spectrum of visible light as wavelengths get larger. |
| UML | Initially created at Rational Software (now part of IBM), this is an industry-standard method of specifying, visualizing, constructing, and documenting the artifacts of object-oriented software systems using a graphical diagram that looks similar to a flowchart. You can use UML to effectively make a blueprint of the software you are developing, thus making additional development easier, as you can refer back to your UML model. |
| Unbuffered memory | Memory modules that do not support Error Checking and Correcting (ECC) or parity checking functionality. |
| UNC | The name given for the naming used when one specifies: \the serverthe volumethe paththen the file name of a file. So, a UNC filename would look like this: \MyserverDocdriveMagazineglossary.doc. |
| Unified Cache | Multiple memory caches, most often L1 and L2 cache, that are treated as a single unit in that they don't ever hold the same information. In non-unified caching, both L1 and L2 could potentially hold parts of the same data. |
| Unified Modeling Language | Initially created at Rational Software (now part of IBM), this is an industry-standard method of specifying, visualizing, constructing, and documenting the artifacts of object-oriented software systems using a graphical diagram that looks similar to a flowchart. You can use UML to effectively make a blueprint of the software you are developing, thus making additional development easier, as you can refer back to your UML model. |
| Uninterruptible Power Supply | A device that contains a battery and some circuitry to supply your computer with power for a limited time (depending on the battery) if there is any sort of interruption in the outlet power. It must switch to battery power fast enough to keep the computer running during an outage. Large UPSes typically use lead-acid batteries like the one in your car. |
| Union | This consists of all of the items from two or more sets, similar to "AND" in a function. For example, the union of {1,2,3} and {3,4,5} is {1,2,3,4,5}. |
| Universal Asynchronous Receiver Transmitter | A chip that standardized serial communications. Its function is to change a byte into a standard sequence of electrical impulses. |
| Universal Data Format | A superset of data formats used with GIS, imaging, mapping, and CAD products. You can access data in UDF format instead of converting it from one format to another, with full geographic information preserved. |
| Universal Disk Format | A file system that supports CD-RW, DVD-ROM, and DVD-Video. It also allows for easily writing more data to CD-R and CD-RW disks with the appropriate software. |
| Universal Naming Convention | The name given for the naming used when one specifies: \the serverthe volumethe paththen the file name of a file. So, a UNC filename would look like this: \MyserverDocdriveMagazineglossary.doc. |
| Universal Resource Locator | This is what is used to give Web addresses for HTML, VRML, WAV, and other files. It simply contains the Internet name of the machine containing the data and the path to the file. URLs are much like the UNC, except specifically for the Internet. The address also includes what protocol should be used, such as HTTP, HTTPS, or FTP. |
| Universal Serial Bus | A serial connection technology that is almost universally available in current PCs. Version 1.x allowed for 12Mbps transfer rates, and this was boosted to 480Mbps for USB 2.0. USB 2.0 competes with FireWire for transmission speed. Even though USB is so ubiquitous, the PS/2 port is still used for keyboard and mouse connection on many new PCs. |
| Unshielded Twisted Pair | Cables that consist of pairs of unshielded wire twisted together. These cables are used for data and telephone networks. They are cheap to produce because they are unshielded, and they get their shielding by being twisted together in pairs. |
| Upgrade | This normally refers to a newer version of software, or a version with an enhanced feature set. If you already own a previous version of the software, you can often purchase an upgrade version for a lower price than a new version. In terms of hardware, you can upgrade your system by adding more memory, or any component that makes your system better or faster. Some graphics cards let you upgrade them by plugging more memory onto the board. |
| Uplink Port | A special networking port on a hub or switch that is used to connect it to a larger network. Often you need a special crossover cable to make this connection function properly. If you think of a network as a tree, the hub (or switch) on top connects to the uplink ports of the hubs (or switches) below it, and so on. |
| UPS | A device that contains a battery and some circuitry to supply your computer with power for a limited time (depending on the battery) if there is any sort of interruption in the outlet power. It must switch to battery power fast enough to keep the computer running during an outage. Large UPSes typically use lead-acid batteries like the one in your car. |
| Upstream | This refers to sending of data from a client machine across the Internet. With cable modems and ADSL, upstream speeds are slower than downstream speeds. |
| USB | A serial connection technology that is almost universally available in current PCs. Version 1.x allowed for 12Mbps transfer rates, and this was boosted to 480Mbps for USB 2.0. USB 2.0 competes with FireWire for transmission speed. Even though USB is so ubiquitous, the PS/2 port is still used for keyboard and mouse connection on many new PCs. |
| User Datagram Protocol | Part of the TCP/IP suite of protocols. UDP is the part of the TCP/IP suite used by applications to transfer datagrams. It is also the part of TCP/IP responsible for port addresses. UDP got the short end of the stick in some ways in that its name isn't included in TCP/IP, but would you really want to call it TCP/UDP/IP? |
| UTP | Cables that consist of pairs of unshielded wire twisted together. These cables are used for data and telephone networks. They are cheap to produce because they are unshielded, and they get their shielding by being twisted together in pairs. |
| UUCP | A UNIX protocol and set of programs most often used to copy files across serial connections and telephone lines. UUCP was often used to transfer e-mail and Usenet news over phone lines when direct Internet connectivity was scarce in small and medium-sized companies. |
| UXGA | A display with 1600x1200 pixel resolution. |
| V.32 | A standard naming convention used in determining modem communications, all starting with "V." This one is for specifying the Hayes standard of bidirectional 9600 baud transmission. |
| V.32bis | The standard that came after V.32 which increased the speed from 9600 baud to 14.4 Kbits per second. |
| V.34 | This was a dramatic improvement for modem communications. It doubled the top speed of the V.32bis standard to 28.8Kbps. |
| V.34+ | This standard was made by US Robotics to indicate that its modems are superior to a standard V.34 modem in that they run at 33.6 KB baud instead of the slower 28.8 KB baud. |
| V.42 | The name given to the standard for transmitting at 2400 baud. |
| V.42Bis | This is not a speed standard like V.32 and V.34, but an error correction and compression method that is hardware-based. Its major improvement comes from knowing when compression will be beneficial and when it will not be. |
| V.90 | The ITU's first standard for 56K modem communications. It superceded X2 and 56kflex to become the ultimate 56K standard. Most X2 and 56kflex modems were able to upgrade to V.90 for free. |
| V.92 | An extension to the V.90 modem transmission standard that adds three new features: quick connect, which speeds up the connection handshake; Modem-on-Hold, for receiving incoming calls without breaking your connection; and PCM Upstream, for speeding up upstream data rates to up to 48Kbps. Previously with V.90, upstream rates were limited to 33.6Kbps. |
| V.Everything | US Robotics' designation for its Courier Dual standard modems, which support all types of analog modem communications. |
| V.Fast | This standard was made between the time of V.32bis and V.34. It is also a 28.8 KB baud speed, but was not as reliable as the approved V.34 standard. |
| Value Added Reseller | An individual or company that resells computer hardware and/or software. They "add value" to the items they sell by integrating or customizing them as needed. VARs are part of the channel. See channel. |
| VAR | An individual or company that resells computer hardware and/or software. They "add value" to the items they sell by integrating or customizing them as needed. VARs are part of the channel. See channel. |
| Variable Bit Rate | A type of encoding of compressed audio that allows for different bitrates in the same file. VBR can reduce file size and increase quality. The file size can be reduced by keeping bit rates low in non-complex parts of audio. Increased quality comes from allowing high bitrates in more complex segments of audio. |
| VAX | A line of 32-bit servers sold by the former Digital Equipment Corp. Initially, VAX computers ran only the VMS operating system, but later versions supported UNIX as well as VMS. |
| VBR | A type of encoding of compressed audio that allows for different bitrates in the same file. VBR can reduce file size and increase quality. The file size can be reduced by keeping bit rates low in non-complex parts of audio. Increased quality comes from allowing high bitrates in more complex segments of audio. |
| VBScript | A Microsoft scripting language that is embedded in many Microsoft applications. Although it allows for powerful interoperability and functionality, it also creates a great deal of security risks unless it is tightly controlled. |
| VCD | This technology was developed by Sony and Philips in 1993, and allows around 70 minutes of compressed MPEG-1 video/audio to be stored on a CD. Typically VCD movies are shipped on two CDs. VCDs were very popular in Asia, and were available before DVD. Even though the VCD format was extended with SVCD, VCDs will probably eventually succumb to the higher quality of DVD. VCD resolution is 352x240 (NTSC) or 352x288 (PAL), which is fairly comparable to VHS resolution of 300x360. |
| VCM | A type of memory developed by NEC. VCM memory adds some low latency SRAM registers onto standard SDRAM, much like EDO compared to Fast Page Mode memory. VC memory never took off, as DDR memory and RDRAM superseded SDRAM. |
| VCR | A device that can record and play back video to and from videotapes (video cassettes). Typical tapes can hold two to 6 hours of video, depending on quality. |
| VDT | An older term for a CRT monitor. It is most often used when the ergonomics of computer monitors or EMF radiation are discussed, such as "Sitting in a room full of video display terminals was thought to lead to migraine headaches, among other things." |
| Vector | A set of scalar numbers that refers to a point in space. Say, for example, you are in a two-dimensional space. A vector may be (5,6), which is 5 units across the X axis and 6 units up the Y axis. See also scalar. |
| Vertical market | An industry or group of companies that can be marketed to in a similar manner because they have similar needs. Common examples of vertical markets include the government, healthcare, and insurance. |
| Vertical Market Application | An application written specifically for a particular vertical market, as opposed to more generic multi-purpose applications such as office suites. One example is a program written for the insurance industry that computes insurance rates. Such an application is useless in any market besides the insurance industry. |
| Very Large DataBase | This refers, unsurprisingly, to a database that is very large in size. How large exactly is not specifically defined, but sizes of around a terabyte or more would fit this moniker. Database technology is driven by the need for fast VLDB solutions, and there are annual VLDB conferences and VLDB journals. |
| Very Large Scale Integration | The amount of transistors that are incorporated in a chip. A VLSI processor has on the order of 100,000 or more transistors, but not over a million. See also ULSI, LSI, MSI, and SSI. |
| Very Long Instruction Word | A microprocessor architecture different from CISC and RISC. VLIW uses encoded instructions that are even more complex than the instructions used in CISC. While RISC took instruction sets in a simpler direction by making instructions smaller, VLIW moves them in a more complex direction by encoding four or more instructions into a single operation. VLIW is used in the Hewlett Packard PA-RISC series of microprocessors, and formed the basis of some of the architecture used in Intel's IA-64 processors. |
| VESA | A group that sets standards for certain peripheral devices and their connectors, such as the VESA Local Bus and VESA standard monitor specification. |
| VESA Local Bus | A 32-bit extension of a 16-bit ISA slot. This architecture predated PCI and allowed users to break the bottleneck that occurred when the ISA bus slowed down graphics speed. It allowed speeds of up to 40MHz, compared to ISA's measly 8.3MHz. The fact that it had twice as many pins to transmit data helped out as well. VL-Bus was big on 486-66 machines when it first came out, but was quickly displaced by PCI. PCI cards have some modest speed advantages and are much smaller. All VL-Bus cards were full-length cards. |
| VGA | A video standard that allows for resolutions up to 640x480 with up to 16 colors at a time. It also allows for 320x200 resolution with 256 colors. Many older games were written to take advantage of the 320x200 resolution because of the comparatively high color depth. SVGA and XGA replaced VGA, but VGA compatibility remains an important part of most graphics cards. If your video driver is messed up, versions of Windows, starting with 95 and NT, let you go in under VGA mode to fix your graphics driver. |
| Video Card | An add-on device in computers that deals specifically with displaying to a monitor. Without one you cannot see what's going on in your computer, and may have to resort to the ancient method of using a printer as a monitor (please don't do that). |
| Video Cassette Recorder | A device that can record and play back video to and from videotapes (video cassettes). Typical tapes can hold two to 6 hours of video, depending on quality. |
| Video CD | This technology was developed by Sony and Philips in 1993, and allows around 70 minutes of compressed MPEG-1 video/audio to be stored on a CD. Typically VCD movies are shipped on two CDs. VCDs were very popular in Asia, and were available before DVD. Even though the VCD format was extended with SVCD, VCDs will probably eventually succumb to the higher quality of DVD. VCD resolution is 352x240 (NTSC) or 352x288 (PAL), which is fairly comparable to VHS resolution of 300x360. |
| Video Display Terminal | An older term for a CRT monitor. It is most often used when the ergonomics of computer monitors or EMF radiation are discussed, such as "Sitting in a room full of video display terminals was thought to lead to migraine headaches, among other things." |
| Video Electronics Standards Association | A group that sets standards for certain peripheral devices and their connectors, such as the VESA Local Bus and VESA standard monitor specification. |
| Video Graphics Array | A video standard that allows for resolutions up to 640x480 with up to 16 colors at a time. It also allows for 320x200 resolution with 256 colors. Many older games were written to take advantage of the 320x200 resolution because of the comparatively high color depth. SVGA and XGA replaced VGA, but VGA compatibility remains an important part of most graphics cards. If your video driver is messed up, versions of Windows, starting with 95 and NT, let you go in under VGA mode to fix your graphics driver. |
| Video Home System | A trademark and industry standard for the tape format used in VCRs. The VHS format features resolution of about 300x360 pixels. |
| Video RAM | Dual-ported memory made specifically for video cards that was very similar to DRAM but was able to receive and send data at the same time. Due to the complexity of this, it was more expensive than DRAM. VRAM was common when Fast Page Mode memory was the best thing going for PCs. |
| Virtual Address eXtension | A line of 32-bit servers sold by the former Digital Equipment Corp. Initially, VAX computers ran only the VMS operating system, but later versions supported UNIX as well as VMS. |
| Virtual Channel Memory | A type of memory developed by NEC. VCM memory adds some low latency SRAM registers onto standard SDRAM, much like EDO compared to Fast Page Mode memory. VC memory never took off, as DDR memory and RDRAM superseded SDRAM. |
| Virtual Classroom | Any means of live or pre-programmed Internet broadcast of information meant to function in a teaching capacity. For example, you could say "see you in the virtual classroom" and meet at a particular URL that is dispensing information. |
| Virtual LAN | This is created when a bunch of physically connected ports are grouped together by network hardware that supports VLANs. These VLANs are each treated as completely separate entities, and can only be joined together by a router. This scheme is useful for grouping departments together for security and minimizing network traffic. |
| Virtual Machine | Generally speaking, this is any non-physical construct that runs within the confines of another real (physical) or virtual machine. For example, an operating system is a type of virtual machine that runs on a computer's BIOS software, which runs on a physical computer. Any piece of software that runs on an operating system (or within the confines of another piece of software) can also be considered a virtual machine. The term and idea of a virtual machine has been used by Sun Microsystems in its description of a program launched by a browser that will run Java programs. Virtual machine also describes specific programs that mimic a computer within a computer, or a simulation of a physical device represented by computer software. |
| Virtual Machine Environment | An operating system developed by ICL (International Computers Limited) for mainframe computers. ICL is a hardware and software manufacturer from the U.K. |
| Virtual Memory | A section of a hard drive used to augment a computer's RAM, or main memory. Different operating systems have different ways of dealing with virtual memory. UNIX and Linux often use a separate hard drive partition dedicated to virtual memory, while Windows uses a file or files on any number of hard drive partitions. However, Linux and UNIX can be configured to use a swap file as needed also. Virtual memory is used when the operating system runs low on physical memory. Virtual memory is also used to swap out lesser used portions of physical memory, freeing it up for other operations. |
| Virtual Memory System | Designed in 1976, this is the operating system that ran on Digital Equipment Corp.'s VAX operating system. Eventually DEC ported VMS to run on the Alpha processor and added POSIX functions into the operating system, renaming it OpenVMS. |
| Virtual Private Network | A "virtual" network constructed by connecting computers together over the Internet and encrypting their communications so that other people cannot understand the communications. The benefit is that people can connect to a local LAN from anywhere on the Internet. This allows easier connectivity and lower phone bills for travelling salespeople. They just sign up with a national ISP and call local POPs from their hotels as they travel the country, easily connecting back to their company's local network. |
| Virtual Reality Markup Language | An enhancement to the HTML format used to make virtual worlds out of Web pages. Its main uses so far include going on walk-throughs of real estate over the Web. |
| Visitor | When a user arrives on a website, he or she is considered one visitor regardless of how many pages at which he or she looks. If a visitor returns to that website later in the day, he or she may be counted as another visitor by logging programs unless you are looking for "unique" visitors and the visitor is identified by cookies or IP addresses. |
| Visual Basic | Asoftware product developed by Microsoft. Its purpose is to bring programming down to a drag-and-drop level to speed up development cycles. In many ways that goal has been achieved. VB's main competitor at one time was Borland's Delphi. Both programs offer similar functionality, with VB based on the BASIC programming language and Delphi based on Pascal. The actual code generated by VB is BASIC, and you can go in and edit the nitty-gritty if you want to. VB was at one time very slow compared to C++, but it has been sped up significantly since those days. |
| Visual Basic Script | A Microsoft scripting language that is embedded in many Microsoft applications. Although it allows for powerful interoperability and functionality, it also creates a great deal of security risks unless it is tightly controlled. |
| Visual C++ | A Microsoft product that is basically VB on steroids. It features a similar visual interface with drag-and-drop functionality, but the code is C++, which is much more robust than BASIC. It's also faster when compiled. |
| VLAN | This is created when a bunch of physically connected ports are grouped together by network hardware that supports VLANs. These VLANs are each treated as completely separate entities, and can only be joined together by a router. This scheme is useful for grouping departments together for security and minimizing network traffic. |
| VLB | A 32-bit extension of a 16-bit ISA slot. This architecture predated PCI and allowed users to break the bottleneck that occurred when the ISA bus slowed down graphics speed. It allowed speeds of up to 40MHz, compared to ISA's measly 8.3MHz. The fact that it had twice as many pins to transmit data helped out as well. VL-Bus was big on 486-66 machines when it first came out, but was quickly displaced by PCI. PCI cards have some modest speed advantages and are much smaller. All VL-Bus cards were full-length cards. |
| VLDB | This refers, unsurprisingly, to a database that is very large in size. How large exactly is not specifically defined, but sizes of around a terabyte or more would fit this moniker. Database technology is driven by the need for fast VLDB solutions, and there are annual VLDB conferences and VLDB journals. |
| VLIW | A microprocessor architecture different from CISC and RISC. VLIW uses encoded instructions that are even more complex than the instructions used in CISC. While RISC took instruction sets in a simpler direction by making instructions smaller, VLIW moves them in a more complex direction by encoding four or more instructions into a single operation. VLIW is used in the Hewlett Packard PA-RISC series of microprocessors, and formed the basis of some of the architecture used in Intel's IA-64 processors. |
| VLSI | The amount of transistors that are incorporated in a chip. A VLSI processor has on the order of 100,000 or more transistors, but not over a million. See also ULSI, LSI, MSI, and SSI. |
| VME | An operating system developed by ICL (International Computers Limited) for mainframe computers. ICL is a hardware and software manufacturer from the U.K. |
| VMEbus | A backplane interconnection bus standard developed by Motorola and others, and now an IEEE standard. It has data bus sizes of 16, 32, or 64 bits, and VMEbus boards can hold CPUs or peripherals. |
| VMS | Designed in 1976, this is the operating system that ran on Digital Equipment Corp.'s VAX operating system. Eventually DEC ported VMS to run on the Alpha processor and added POSIX functions into the operating system, renaming it OpenVMS. |
| Voice over IP | The practice of using an Internet connection to pass voice data using IP instead of using the standard public switched telephone network. This allows a remote worker to function as if he or she were directly connected to a PBX even while at home or in a remote office. As well, it skips standard long distance charges, as the only connection is through an ISP. VoIP is being used more and more to keep corporate telephone costs down, as you can simply run two network cables to a desk instead of separate network and data cables. VoIP runs right over your standard network infrastructure, but it also demands a very well-configured network to run smoothly. |
| VoIP | The practice of using an Internet connection to pass voice data using IP instead of using the standard public switched telephone network. This allows a remote worker to function as if he or she were directly connected to a PBX even while at home or in a remote office. As well, it skips standard long distance charges, as the only connection is through an ISP. VoIP is being used more and more to keep corporate telephone costs down, as you can simply run two network cables to a desk instead of separate network and data cables. VoIP runs right over your standard network infrastructure, but it also demands a very well-configured network to run smoothly. |
| Volt | The standard unit of electric potential. It is defined as the amount of electrical potential between two points on a conductor carrying a current of one ampere while one watt of power is dissipated between the two points. |
| Voltage | A measure of an amount of volts. |
| Volume | A drive or set of drives seen as a single entity by a Novell NetWare file server. It is the highest level of the NetWare directory structure. Volumes must be mounted to be recognized by the NetWare operating system, and can be unmounted to be taken offline. |
| VRAM | This is dual-ported memory made specifically for video cards that was very similar to DRAM but was able to receive and send data at the same time. Due to the complexity of this, it was more expensive than DRAM. VRAM was common when Fast Page Mode memory was the best thing going for PCs. |
| VxD | A device driver that runs under the Windows operating system. It runs as part of the OS kernel and has access to kernel memory, running processes and hardware. Starting with Windows 95, these files have the file extension .vxd, and before that with Windows 3.x, they had the extension .386. |
| Wafer | A flat, round piece of silicon that is used in the manufacture of microprocessors. Fabrication plants, or fabs, typically will take a wafer and carve many microprocessors into it. Over the years wafer size has been increasing so that more chips can be fit on a single wafer, from 6" to 8" to 12" in diameter in some plants today. Wafers are created by taking a cylinder of silicon and slicing it, much like taking a loaf of bread and cutting slices, but to much more precise measurements. |
| Wake-on-LAN | A technology developed by the IBM and Intel Advanced Manageability Alliance where a computer motherboard can turn itself on (and off) based on signals arriving at the computer's network card. Thus, if all your client machines support Wake-on-LAN you could remotely turn all your client machines on during a Saturday afternoon and perform a network-based upgrade without actually going to each machine and powering it on. WOL is certainly a useful technology for network administrators. |
| Wallpaper | An optional background graphic used in a graphical user interface. |
| Wares | A slang term derived from the word "software." This term generally refers to pirated or cracked software. Chop off the "soft" part and you are left with "ware." There is no singular form of warez, or "wares" as they are also called. |
| Water Cooling | This type of cooling differs from air cooling in that water is used to remove heat from a heatsink that makes contact with a hot microprocessor or other device. Ultimately the water may actually exchange its heat with metal and air, or it could be cooled by a refrigeration unit. Water cooling is more efficient than air cooling, especially if the water is refrigerated. |
| Watt | The electrical unit of power, which is energy transferred over a unit of time. Often it is used to describe the amount of heat generated by a microprocessor. |
| Wattage | A measure of an amount of watts. |
| Wav | A sound file format introduced in Windows 3.1 with the .wav file extension. Files with the .wav extension are digital representations of sound and typically take up a good deal of space to store (typically 50 MB for a 5-minute song). If you use software to rip files from an audio CD the result is usually stored in .wav format. Standard Windows sounds are still in .wav format. |
| WaveTable | A bit of ROM on sound cards that stores standard sounds (as .wav files) for instruments instead of generating them from FM sounds. This gives a much more realistic sound to music in games and MIDI files. Ideally, sound cards also allow programs to load their own instruments in as well for added effects. |
| Wavetable Synthesis | A method of creating music based on a table of complex sounds. A wavetable could contain a realistic piano sound or guitar sound, which can then be manipulated to create very complex sounds. See also FM synthesis. |
| WCDMA | A 3G standard that increases the throughput of data transmission of CDMA by using a wider 5MHz carrier than standard CDMA, which uses a 200KHz carrier. WCDMA allows for data transfer rates as high as 2Mbps. |
| Web | A synonym for the term "World Wide Web," often referred to as "The Web." |
| Web Developer | Grown up Webmasters are Web Developers. Generally, if you are a Web Developer you have a range of Web skills, from managing a webserver to coding HTML, CGI scripts, and even creating spiffy graphics as needed. |
| Web Portal | A term coined to describe the large search engine sites, such as Yahoo! and Lycos, that have branched off to offer a wide variety of services. The idea is that a Web user would peer at the Web by using only one website: the portal. For example, you go to a portal to do searches, get stock quotes, buy things, etc. It would be your everything site. Each portal site wants to offer one of each type of service so that a user never has to leave the site. |
| Webmaster | A blanket term that refers to the person responsible for running a website. It is associated more with server administration and HTML coding than other Web development, such as CGI scripting. |
| Webserver | A machine, or software on a machine, that replies to data requests from a browser using the WWW protocol called HTTP, allowing people to access HTML files. |
| Website | This term describes a particular company's, user's, or organization's Web pages served up by a webserver. It may be split across multiple servers or URLs, but it is one group of HTML pages with a particular association. For example, the Geek.com website spans multiple servers and includes the domain names ChipGeek, PDAGeek, and Geek.com. |
| WFM | An Intel hardware specification for easier management of desktop PCs in a networked environment. The specification calls for computers to be compatible with a pre-boot protocol that can be used to update the system or perform other management options. Also, the computer must be compatible with network/desktop management applications. |
| Wheel Mouse | A mouse controller that, besides the usual buttons, also has a wheel device built in that is most often used to scroll up and down windows that are longer than the screen, such as long Web pages or documents. |
| White hat | A hacker with benign intentions. For example, if a hacker encounters a security hole and the first thing he or she does is explain the problem to the people who run the system that allows the security hole--without letting the knowledge out publicly--that hacker would be described as a white hat hacker. This term comes from old cowboy movies where the good guy wore a white hat. |
| White Noise | This is technically sound with a uniform frequency spectrum over a wide range of frequencies. Non-technically, white noise is any unobtrusive background noise, such as the hum of a fan, the sound of rain, or the sound of a channel that isn't coming in properly on an old television. Often white noise is imitated and generated to drown out other obtrusive sounds. |
| White Paper | A complete description of a particular technology, from overview to the nitty-gritty details. It is produced by the company that created that technology, as opposed to a FAQ, which can be created by anyone. |
| Wide Area Information Service | A client/server method of accessing databases stored on multiple servers. You use a WAIS client to connect to a WAIS server and search the databases that the WAIS server has cataloged. WAIS is not much use to the average Internet user today, but is still used by some to access information that is not readily available in HTML form yet. |
| Wide Area Network | Any network that spans more than one location. Typically at least one of the locations is fairly remote. Compare this to a MAN that may encompass several closely located buildings, such as a college campus. |
| Wide SCSI | An improvement to the old narrow SCSI that allows for faster throughput by increasing the number of pins used to connect the drive to the controller from 50 to 68. Wide SCSI doubled the throughput of narrow versions of SCSI, but was generally more expensive due to the additional pins and marketing strategies. Of course you were getting twice the performance, so what's a few bucks? |
| Wideband CDMA | A 3G standard that increases the throughput of data transmission of CDMA by using a wider 5MHz carrier than standard CDMA, which uses a 200KHz carrier. WCDMA allows for data transfer rates as high as 2Mbps. |
| Windows | A rectangular shaped area on the screen of any GUI that contains a program. It also refers to a family of operating systems developed by Microsoft. The family includes Windows 3.x, 9x, Me, NT, 2000, XP, and 2003. |
| Windows 2000 | At first this operating system was called Windows NT 5, until Microsoft renamed it to Windows 2000. Windows 2000 was mainly a 32-bit operating system using the NT code base, but 64-bit versions also came out for Intel's Itanium processors. Windows 2000 ads new functionality into Windows NT, such as support for USB and other new devices, built-in DirectX 7.0, and many other features. |
| Windows 3.x | The first accepted commercial version of Windows. There was a version 2.x that was available at one point, but Windows didn't achieve success until 3.x arrived, putting a Windows GUI directly on top of DOS 5. |
| Windows 95 | A 16- and 32-bit operating system that builds on DOS and Windows 3.x to support 32-bit operations, additional hardware, and a more usable interface. This was a true breakthrough product for Microsoft, allowing game developers to run games inside of the Windows OS instead of separately in DOS. It was designed for the consumer market. |
| Windows 98 | This operating system was designed by Microsoft and adds additional hardware support and integrated browsing onto the Windows 95 platform. This OS is still partially 16-bit, a full 15 years after Intel released its first 32-bit processor, the 386. |
| Windows CE | This was initially the name for Microsoft's mobile operating system designed for PDAs. Initial Windows CE devices offered color screens, and a fairly direct port of the Windows user interface. The Windows CE platform has been renamed by Microsoft to Pocket PC. |
| Windows for Workgroups | Officially this was called Windows 3.11 for Workgroups, and it added some basic networking functionality to the standard Windows 3.1 operating system. |
| Windows Internet Naming Service | A Windows-specific method of name resolution where a WINS server translates a NetBIOS name into an IP address. |
| Windows Management Instrumentation | Microsoft's answer to DMI. Microsoft felt that DMI didn't fully exploit Windows capabilities and was incomplete. Microsoft developed WMI to be an easier way of collecting management data from Windows OSes. |
| Windows Me | This Microsoft Windows operating system added many UI enhancements and clutter that actually made it less stable and more hated than Windows 95 and 98. No improvements to the core were made for stability or to enhance the combination 16- and 32-bit mess under the hood. This was Microsoft's last version of Windows containing pieces of 16-bit DOS guts, and good riddance. |
| Windows Media Audio | A Microsoft-developed audio codec that offers sampling rates of 8 to 48KHz. Files of this type typically have the file extension ".wma," and Microsoft is aggressively pushing WMA as an alternative to the popular MP3 audio format, making WMA the default format for its Media Player, which now ships with Windows by default. WMA can create files that sound similar to MP3 files at a given quality and take up less disk space. |
| Windows NT | A full 32-bit operating system developed by Microsoft to be a very stable operating system to be used on servers and business machines. It was developed from the ground up to be fully 32-bit without much worry about DOS compatibility. The core of Windows NT code has been updated for Windows 2000 and XP. |
| Windows RAM | A type of memory chip, or RAM, that was commonly used at one time in graphics cards on PCs. It is dual-ported so that graphics information can be displayed at the same time that it is being refreshed, much like with VRAM. This can give an increase in display speed over conventional memory. |
| Windows Sockets | An API designed to help inconsistent TCP/IP stacks talk together and be accessed properly by Windows 3.x programs. |
| Windows XP | The friendly-faced, updated version of Windows 2000, with an almost cartoonish interface that will surely be looked back upon with a wince. XP started to take real "advantage" of the Internet by including numerous hooks and links to Microsoft's website to improve various functionality, and that is part of what made this operating system so controversial. Also, at long last, it moved the Windows NT code-base onto consumer machines, allowing home users to get the benefits of stability that Windows Me didn't offer. Many hold-outs prefer to stick with Windows 2000. |
| Wine | An implementation of Windows 3.x and Win32 APIs on top of X-Windows. Wine runs on Linux and UNIX, and allows Windows programs to run. Wine was created in 1993 and continues to be updated. |
| WINS | A Windows-specific method of name resolution where a WINS server translates a NetBIOS name into an IP address. |
| Wintel | The common term for computers using Intel microprocessors and running Windows. Thus Windows/Intel becomes Wintel. Often this is used as a slur towards these type of machines; however, it can be a friendly reference as well. Many people have referred to the Wintel monopoly, since 90% of computers sold in the late 1990s had this configuration. |
| Wire-feet | The actual length of the copper wire connecting the end user to the telephone company central office. This measure is used to determine the eligibility of the end user for receiving various DSL services. |
| Wired For Management Baseline | An Intel hardware specification for easier management of desktop PCs in a networked environment. The specification calls for computers to be compatible with a pre-boot protocol that can be used to update the system or perform other management options. Also, the computer must be compatible with network/desktop management applications. |
| Wireless Application Protocol | A proposed standard that allows for transfer of data securely between wireless devices, such as PDAs, cellphones, pagers, or other combinations of those devices. WAP supports many different wireless networks. |
| Wireless Local Loop | This is simply a wireless connection of a telephone in a home or office to a fixed telephone network. Using industry technology, it is an implementation of subscriber loops to connect devices over a multiple access radio system to the Public Switched Telephone Network (PSTN). It differs from a standard local loop in that the connection to the telephone system is made wirelessly instead of with cables. |
| Wireless Markup Language | Part of the Wireless Application Protocol (WAP) , allowing text portions of Web content to be separated from graphical content for display on wireless devices. |
| Wizard | An "enhancement" to programs that makes them easier to operate by guiding you through a process, step by step. Often wizards are scoffed at by experienced users, who prefer to do things the hard way. |
| WLL | This is simply a wireless connection of a telephone in a home or office to a fixed telephone network. Using industry technology, it is an implementation of subscriber loops to connect devices over a multiple access radio system to the Public Switched Telephone Network (PSTN). It differs from a standard local loop in that the connection to the telephone system is made wirelessly instead of with cables. |
| WMA | A Microsoft-developed audio codec that offers sampling rates of 8 to 48KHz. Files of this type typically have the file extension ".wma," and Microsoft is aggressively pushing WMA as an alternative to the popular MP3 audio format, making WMA the default format for its Media Player, which now ships with Windows by default. WMA can create files that sound similar to MP3 files at a given quality and take up less disk space. |
| WMI | Microsoft's answer to DMI. Microsoft felt that DMI didn't fully exploit Windows capabilities and was incomplete. Microsoft developed WMI to be an easier way of collecting management data from Windows OSes. |
| WML | Part of the Wireless Application Protocol (WAP) , allowing text portions of Web content to be separated from graphical content for display on wireless devices. |
| WOL | A technology developed by the IBM and Intel Advanced Manageability Alliance where a computer motherboard can turn itself on (and off) based on signals arriving at the computer's network card. Thus, if all your client machines support Wake-on-LAN you could remotely turn all your client machines on during a Saturday afternoon and perform a network-based upgrade without actually going to each machine and powering it on. WOL is certainly a useful technology for network administrators. |
| Word | A group of bits of data regarded as a whole while programming or transferring data. Often a word is 8 bits in length, also referred to as a byte. This is also the name of Microsoft's word processor. |
| Word Size | The number of bits of data stored in a CPU register. Typically the number is a power of 2, with 8, 16, 32, and 64 being common. You have to deal with word size when doing certain data manipulations while programming. |
| Workstation | A high-powered computer, one step below a minicomputer and a step above a microcomputer. The term often refers to fairly powerful dual-processor computers used to generate 3D images or manipulate 2D images or sound. Often workstations require very powerful graphics setups. |
| World Wide Web | This is basically a means of communicating text, graphics, and other multimedia objects over the Internet. Web servers on the Internet are set to respond to particular requests sent on TCP/IP port 80 by sending HTML documents to the requester. The requester usually uses a browser to receive this data. Think of the Internet as a 100-lane highway, and the Web as one of those lanes. Of course traffic in the Web lane is probably very high compared to traffic in most other lanes. |
| World Wide Web Consortium | An industry group created to design and promote standards to increase the functionality of the Web. The W3C was initially established in collaboration with CERN, the creator of the World Wide Web. |
| WRAM | A type of memory chip, or RAM, that was commonly used at one time in graphics cards on PCs. It is dual-ported so that graphics information can be displayed at the same time that it is being refreshed, much like with VRAM. This can give an increase in display speed over conventional memory. |
| Write Once Read Many | A type of drive/media that allows you to write to it permanently; however, you cannot erase what you've written. CD-R is a form of WORM drive. |
| Write Protect Tab | This phrase was initially coined for older floppy diskettes that needed to be write-protected by placing a tab or sticker over a notch that told a floppy drive that the disk was write-enabled. With the standard 3.5" floppy disks, the write protect tabs are replaced by small plastic parts that can be enabled by setting them to up or down positions. |
| WTX | A computer form factor for motherboards and cases that is designed for mid-range workstations. WTX motherboards can be a maximum of 14" by 16.75", and feature support for a flexible I/O board that allows OEMs to differentiate their designs by including different I/O ports. |
| WWW | This is basically a means of communicating text, graphics, and other multimedia objects over the Internet. Web servers on the Internet are set to respond to particular requests sent on TCP/IP port 80 by sending HTML documents to the requester. The requester usually uses a browser to receive this data. Think of the Internet as a 100-lane highway, and the Web as one of those lanes. Of course traffic in the Web lane is probably very high compared to traffic in most other lanes. |
| X Window System | A consortium-developed, open-standard, device-independent GUI system that is most commonly found on UNIX and Linux operating systems and invoked with the "startx" command. The X Window System was initially developed in 1984 at MIT and called Project Athena. In 1986 the X Consortium was formed to further the development of the GUI. The torch was passed to the Open Group in 1997, and now resides at x.org on the Web. The GUI system works by running an X Server on the client machine that manages the windows, or X Clients. The X Window System uses the client/server architecture in and of itself. |
| X-Windows | A consortium-developed, open-standard, device-independent GUI system that is most commonly found on UNIX and Linux operating systems and invoked with the "startx" command. The X Window System was initially developed in 1984 at MIT and called Project Athena. In 1986 the X Consortium was formed to further the development of the GUI. The torch was passed to the Open Group in 1997, and now resides at x.org on the Web. The GUI system works by running an X Server on the client machine that manages the windows, or X Clients. The X Window System uses the client/server architecture in and of itself. |
| x86 | The 32-bit instruction set used by most PCs. It originated with the Intel spec of the 8088, which then went to the 8086. Since then increments have come by changing the first number to 80286, 80386, "486", and then Pentium and beyond. The reason that the newer chips are actually named is because the numbers can't be copyrighted, and Intel needed to distinguish its chips from competitors' products. |
| XGA | This started out as IBM's term for a computer monitor resolution standard of 1024x768 pixels and 16-bit color. IBM released XGA monitors and graphics cards for its PS/2 computers, but unfortunately the standard was interlaced, and ran on 14" monitors. Nowadays XGA just means 1024x768. Laptop makers often mention that their screens are XGA, meaning that they support that resolution. |
| XLR Cable | An analog audio cable normally used to connect microphones to professional audio devices. It has three pins and provides a balanced input, as opposed to an unbalanced or single-ended RCA connector. |
| XOR | An operation that can be executed on two or more binary strings. XOR returns true, or "1", if only one of the two strings contains a 1 at a particular bit position, and a false, or "0", if both strings contain 0s or 1s at both positions. It is similar to the behavior of OR, but is false when both bits are positive (thus "exclusive" one or the other, but not both). For example (0 XOR 0) = 0, (0 XOR 1) = 1, (1 XOR 0) = 1, (1 XOR 1) = 0. Thus: (0011 OR 1001) = 1010. |
| Yottabyte | This is 2^80 bytes, or 1024 zettabytes. See also zettabyte. |
| Z-Buffering | This tracks the depth of each triangle in a 3D graphics representation, from the perspective of the viewer, to ensure that objects behind other objects in a scene don't appear until the viewer has them in his or her line of sight. This is why you can't see through walls to what lies behind, but why you can play multiplayer Quake and have people at many different areas in a level. |
| ZAK | A software kit from Microsoft originally for Windows NT that can prevent various user actions, such as installing software or changing desktop configurations. |
| ZAW | This version of the Windows operating system from Microsoft allows for various easy administration and management options, such as storing user software and settings on the network so that people can log into any machine on a network and retain the same personal settings. Basically it turns your PC into an NC. |
| Zero Administration Kit | A software kit from Microsoft originally for Windows NT that can prevent various user actions, such as installing software or changing desktop configurations. |
| Zero Administration Windows | This version of the Windows operating system from Microsoft allows for various easy administration and management options, such as storing user software and settings on the network so that people can log into any machine on a network and retain the same personal settings. Basically it turns your PC into an NC. |
| Zero Insertion Force socket | A socket designed to accept a PGA chip, such as most common CPUs produced today. The ZIF socket allows you to plug in a PGA chip with no pressure required. This is a big advantage because older sockets required you to push the chip in with equal force on all sides or risk bending the pins. It's not fun to bend pins on the new processor you just bought, especially when some server chips cost well over US$1,000. |
| Zettabyte | This is 2^70 bytes, or 1024 exabytes. See also exabyte. |
| ZIF socket | A socket designed to accept a PGA chip, such as most common CPUs produced today. The ZIF socket allows you to plug in a PGA chip with no pressure required. This is a big advantage because older sockets required you to push the chip in with equal force on all sides or risk bending the pins. It's not fun to bend pins on the new processor you just bought, especially when some server chips cost well over US$1,000. |
| Zone | A term having to do with DNS. Each top-level domain name, such as Geek.com, is considered a zone, where subdomains such as server1.geek.com or www.geek.com are managed by their own DNS servers. Geek.com's Zone of Authority is all the subdomains under Geek.com. |
| Zone File | A list of DNS data elements, referred to as resource records, for a Zone of Authority. |
| Zone of Authority | A term having to do with DNS. Each top-level domain name, such as Geek.com, is considered a zone, where subdomains such as server1.geek.com or www.geek.com are managed by their own DNS servers. Geek.com's Zone of Authority is all the subdomains under Geek.com. |
| Zone Transfer | The act of replicating a zone file from one DNS server to another. |
| Zoomed Video | A PC Card (PCMCIA) slot that is linked directly to the VGA controller. It allows easier implementation of MPEG video decoding and other video/TV features in laptops. |
| anonymizer | a privacy service that allows a user to visit Web sites without allowing anyone to gather information about them. |
| back door | a means of access to a computer program that bypasses security mechanisms. A programmer may sometimes install a back door so that the program can be accessed for troubleshooting or other purposes, but an attacker may exploit or use a back door to get unauthorized access to information or install spyware. |
| backdoor | a means of access to a computer program that bypasses security mechanisms. A programmer may sometimes install a back door so that the program can be accessed for troubleshooting or other purposes, but an attacker may exploit or use a back door to get unauthorized access to information or install spyware. |
| bluesnarfing | theft of information from a wireless device using Bluetooth transmission. By exploiting a vulnerability in the way Bluetooth is implemented, an attacker can access information -- such as the user's calendar, contact list and e-mail and text messages -- without leaving any evidence of the attack. |
| browser hijacker | a type of malware program that alters your computer's browser settings so that you are redirected to Web sites that you had no intention of visiting. Often works in conjunction with spyware. |
| bundling | the practice of including multiple products in a package deal. Frequently, spyware is bundled with freeware or shareware products. |
| cache poisoning | the corruption of an Internet server's domain name system table by replacing an Internet address with that of another, rogue address. When a Web user seeks the page with that address, the request is redirected by the rogue entry in the table to a different address. At that point, a worm, spyware, Web browser hijacking program, or other malware can be downloaded to the user's computer from the rogue location. Cache poisoning is also called domain name system (DNS) poisoning or DNS cache poisoning. |
| cookie poisoning | the modification of a cookie by an attacker to gain unauthorized information about the user for purposes such as identity theft. |
| data integrity | the assurance that information can only be accessed or modified by those authorized to do so. |
| drive-by download | a download that occurs without user knowledge or consent. Can occur as the result of visiting a specific Web site or by clicking a deceptive button on a pop-up window. |
| evil twin | a home-made wireless access point (hot spot) that masquerades as a legitimate one to gather personal or corporate information without the end-user's knowledge. |
| Kazaa | a popular peer-to-peer file-sharing program that was widely reported to include spyware, especially in its earlier incarnations. |
| keystroke logger | a small hardware device or a program that records each keystroke typed on a particular keyboard for report back to an interested party, such as a marketer or an employer. Also used by unscrupulous individuals to gain access to information for identity theft and other illicit purposes. |
| keylogger | a small hardware device or a program that records each keystroke typed on a particular keyboard for report back to an interested party, such as a marketer or an employer. Also used by unscrupulous individuals to gain access to information for identity theft and other illicit purposes. |
| key logger | a small hardware device or a program that records each keystroke typed on a particular keyboard for report back to an interested party, such as a marketer or an employer. Also used by unscrupulous individuals to gain access to information for identity theft and other illicit purposes. |
| identity theft | illicit impersonation of a victim by accessing personal information, often used to obtain credit, merchandise, and services in the name of the victim, or to provide the thief with false credentials. Spyware is sometimes used to gather such information. |
| malware | short for "malicious software", includes spyware, viruses, worms, and Trojan horses. Spyware is generally used for marketing purposes and, as such, not really malicious although it is generally unwanted. However, spyware can also be used to gather information for identity theft or other clearly illicit purposes. |
| personalization | using information gathered about individual visitors to create customized pages for them and enhance customer service or e-commerce sales |
| phishing | a method of tricking people into giving up their personal information. Sometimes associated with spyware; for example, perpetrators may get victims to click on a link that takes them to a Web site where they are subject to a drive-by download. |
| pop-up download | a download initiated through a pop-up window, often engineered to trick the user into agreeing to a download, which may contain spyware. |
| potentially unwanted program | a program that may be unwanted, such as adware or spyware, despite the possibility that users consented to download it. |
| pseudonymous profile | a collection of information about a particular computer user that identifies the user either by their computer's IP address or by a randomly-generated nickname. Often used for personalization or marketing purposes. |
| rootkit | a set of programs used to hack into a system and gain administrative-level access. May also monitor traffic and keystrokes; create a "backdoor" into the system for the hacker's use; alter log files; attack other machines on the network; and alter existing system tools to circumvent detection. |
| transient cookie | a small file that stores user information temporarily and disappears when the browser is closed. Because user information is not stored on the hard drive, it cannot be accessed when the session is finished. |
| Trojan | a program in which malicious code is contained inside apparently harmless programming or data in such a way that it can get control and do its chosen form of damage, such as ruining the file allocation table on your hard disk or tracking and reporting user information. |
| URL poisoning | a method of tracking Web user behavior by adding an ID number to the URL line in a Web browser when a user visits a particular site. This ID number can then be used to determine which pages on the site the user visits thereafter. |
| war driving | the act of locating and possibly exploiting connections to wireless local area networks while driving around a city or elsewhere. Because a wireless LAN may have a range that extends beyond an office building, an outside user may be able to intrude into the network, obtain a free Internet connection, and possibly gain access to company records and other resources. |
