Appendix Glossary A

In the left margin you will find links to the glossary categorised alphabetically. Some of the pages are quite long and may take a few moments to load if you use a modem. This glossary is always being updated.

Glossary - A

A/X - A video editing term. Where "A" usually represents your primary source deck, and "X" represents a live source.

A: - This refers to the "A" "Drive" on the computer. Usually a floppy disk drive. It is the mechanism which operates using external, removable floppy disks, rather than the fixed hard drive. Programs run slower when run from a floppy drive.

Accelerated Graphics Port - (AGP) An Intel developed interface that enables high speed graphics. Graphics data move between the PC's graphics controller and computer memory directly, instead of being cached in video memory.

Accelerates - Instead of processing sound on the host CPU, sound is processed locally on the soundcard, freeing up CPU cycles.

Access - Read, write or update information on some storage medium (such as a disk). The operation of reading, writing or updating stored information.

Access Time - The average time (in nanoseconds) for RAM to complete one access. Access Time is composed of address set-up time and latency (the time it takes to initiate a Request for data and prepare access).
The interval between the time a request for data is made by the system and the time the data is available from the drive. Access time includes the actual seek time, rotational latency, and command processing overhead time.

Acoustic Suspension - Also called air suspension, acoustic-suspension was patented in 1949 by Harry Olsen. In the 1950s, the design was elaborated upon by Acoustic Research. Acoustic- suspension speakers are held inside a sealed enclosure. The speaker's inward and outward movements control the air inside the box, giving low sounds, such as from subwoofers.

Acquire - To transfer a file from an analog source such as a scanner.

Acrobat - Acrobat is the essential program in Adobe's electronic document distribution model. Using Acrobat, the creator of a document can export content created in a page layout or graphic generation program in the PDF (Portable Document Format). This document can then be viewed and printed by anyone who has a copy of the Acrobat Reader software, which is available free of charge from Adobe. This process demonstrates clearly that free software does indeed make the world a far better place.

Active Cooling - A processor cooling solution that uses not only passive heat dissipation, but also a fan or similar cooling device to remove heat from the CPU.

Active Matrix - A type of flat-panel liquid crystal display (LCD) that delivers better clarity and contrast than the passive-matrix display.

Active Server Pages - A specification for a dynamically created web page that contains either Visual Basic or Javascript code. Active server pages are similar to CGI scripts, but they enable Visual Basic programmers to work with familiar tools.

ActiveX - A set of Microsoft technologies that combine two other Microsoft technologies: OLE (Object Linking and Embedding) and COM (Component Object Model).
ActiveX is a set of standard controls that can be used by web developers to infuse websites with functionality that more closely resembles application-level software than traditional static web content. It is not a program or a programming language, but an arsenal of tools that can be used to enhance Internet delivery of information and functionality. While ActiveX is a means to deliver very rich content to remote Internet users, it is not supported by all browser/client environments. A website that relies solely on ActiveX content may be endlessly cool to users whose computers are equipped to handle it, but completely bereft of coolness to those users who are not set up to take advantage of the technology.

Activity Light - An LED that verifies that the hardware is working, communicating with the network and that data is being transmitted through the device.

Actuator - The internal mechanism that moves the read/write head to the proper track.

Adaptive Equipment - Devices of many varieties, some computer controlled or activated, designed to assist people with physical limitations.

Ad Banner - An advertisement, usually displayed in a rectangular box, that contains a hyperlink pointing to the advertiser's Web page or buffer page. Ad banners are the most common method of advertising on the World Wide Web. Costs can run anywhere from free, to upwards of £100,000 per month depending on the popularity of the host site and the number of page impressions the particular page containing the banner receives.

ADC - Analog to Digital Converter. A hardware device that changes analog data to digital form.

Address - A specific site (www, ftp, gopher) or "mailbox" (e-mail) on the Internet, often the mailbox of a particular user. If referring to e-mail, an address will usually contain the "at" sign: @. An address is often rendered in lower case. Example: joebloggs@btinternet.com.

Address Lines - The number of address lines, or "address pins" on a microprocessor determine how much memory the chip can address. The amount of addressable memory can be calculated as 2^#address_lines (two raised to the power of the number of address lines). A microprocessor with 32 address lines can address 232 bytes of memory (4 G Bytes).

ADSL - Asymmetric Digital Subscriber Line. A modem technology that simultaneously delivers data, video, and voice over existing copper telephone lines. It receives data at rates from 1.5 MBps to 9 MBps, and sends data upstream from 16Kbps to 640Kbps. It requires a special ADSL modem.

Agent - Software operating in the background that performs an automatic and silent task such as information gathering.

AGP - Accelerated Graphics Port. A slot found on all Super7 and Slot 1 motherboards designed to provide high-performance graphics when a suitable AGP graphics card is connected. AGP graphics cards are particularly well-suited to today's advanced games. No current computer has more than one AGP port. ATI, Matrox, Creative Labs, Diamond, and NVidia are among the leading vendors providing state-of-the-art AGP graphics cards. Some graphics cards are said to support "AGP 1X." This is basically a 66 MHz PCI variant; better cards support AGP 2X, for enhanced texture handling. Note, however, that an AGP 1.0 connector on a motherboard can support AGP 2X. "AGP 4X," with still higher performance, emerged in late 1999.
AGP is an expansion bus developed by Intel specifically for the videocard subsystem. It operates independent of the PCI bus and normally runs at 66MHz (i.e., 1x). When you see multipliers attached to AGP, such as 2x or 4x, they refer to how much faster the bus will run. 2x means 66MHz x 2, or 133MHz.

AGP Aperture - If you have an AGP video card installed, you may be able to change this setting. This value can usually be set in your computer's BIOS. The AGP Aperture is 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 you have on your video card.

ALGOL - (Algorithmic Language) developed in the 1950s and early 1960s by an international committee, an early programming language that was the basis for Pascal.

Alias - "Aliasing" is the name for the undesirable "stairstep" effect that is often created when graphics are stored digitally. Aliasing is also referred to as "jaggies" by those who feel the need to make up a cute name for everything. In the Macintosh world, the term "alias" also refers to a pointer file that actually represents another file.
A name that is substituted for a more complicated name. For example, a simple alias may be used instead of a more complicated mailing address or for a mailing list.

Allocation - The process of assigning particular areas of the disk to particular data or instructions.

Allocation Unit - An allocation unit is a group of sectors on the disk that can be reserved for the use of a particular file. On hard disks for small computer systems, the allocation unit is usually in the form of a sector, block, or cluster.

Alpha - A 64-bit microprocessor manufactured by Digital Equipment Corporation.

Alpha Blend - The ability to give a pixel a value that will render it solid, invisible, or partially transparent. The process is often used in games to depict special effects, such as explosions and weapons discharge. When mapped onto polygons, alpha-blending can simulate semitransparent objects, such as water and glass.

Alphanumeric Characters - The letters and digits on the standard keyboard.

Alt Key - A key labelled ALT which is used in combination with other keys in order to carry out specified functions in a program. ALT-C means that first the ALT key is depressed, then the letter "C" is depressed while holding the alt down in position.

AMD - Prior to the release of the K6-III (below), the K6-2 was the best performing member of the Pentium-compatible family of Socket 7 processors. This processor, developed by Advanced Micro Devices, is pin-compatible with Intel's original Pentium (not the Pentium II).

AMD K6III - A higher performance version of the K6-2, thanks to a so-called "Tri-level" cache design and improved manufacturing process. The K6-III is roughly comparable in performance to the Pentium II.

AMR - Audio Modem Riser. A connector that lets motherboard makers implement audio and modem connectors on a motherboard.

Analog - Describes any information that has been translated into a corresponding physical change, such as electric current - any information may be converted to analog. Technologically inferior to digital because of signal degradation (the signal or data strength is weaker at a distance with analog data).

Anchor Points - Points HTML links link to.

Animated GIFs - A graphics interchange format and a bit-map graphics file format containing multiple layers. When viewing these layers in succession, the image can appear to be moving or animated.

Animation - The use of moving images on a computer screen. At present, much of the moving video we see must be called up from data stored on a disk or CD-ROM.

Anisotropic Filtering - Conventional texture filtering techniques do not compensate for anisotropy - the elongation of the screen pixel when it is mapped into texture space. This results in either blurring or aliasing, depending on the choice of texture level-of-detail. To achieve sharp textures, a card can use anisotropic filtering, a process that involves an elliptical kernel whose shape and orientation depends on the projection of the destination pixel onto the texture map.

Annie - (orphan annie) A Website or particular Web page that has not been updated in a long time.

Anonymous FTP - A method for downloading public files using the File Transfer Protocol (FTP). Anonymous FTP is called anonymous because you don't need to identify yourself before accessing files. In general, you enter the word anonymous or ftp when the host prompts you for a username; you can enter anything for the password, such as your e-mail address or simply the word "guest". In many cases, when you access an anonymous FTP site, you won't even be prompted for your name and password.
You can use the Archie system to obtain a list of anonymous FTP sites and files available on each site.
Many FTP sites are protected. Unlike anonymous FTP sites, these restricted FTP sites can only be accessed by individuals who enter a valid username and password.

ANSI - (American National Standards Institute) - The US organisation responsible for setting information technology standards.
Pronounced AN-SEE. Generally refers to a type of colour graphic screen, which is relatively easy to draw and which is used for colour menus, etc.

Anti Alias - Image processing designed to eliminate or prevent the stairstep effect often encountered in digital imaging. Although it may sound a little goofy, anti-aliasing actually achieves crisper image quality by adding an artificial blur to an image.

Anti Aliasing - A technique that smoothes the edges of diagonal lines on the screen. Without anti-aliasing, diagonal lines often have a "jaggy" appearance caused by the stair-step effect of the pixels. Anti-aliasing blurs the edges of the lines. In 3D graphics, bilinear and trilinear filtering provides anti-aliasing for textures.

Antivirus Program - Software that protects a computer from the introduction of destructive programs (viruses) introduced either by corrupt floppy disks or by electronic data transfer over a network such as the Internet.

AOL - "America Online" AOL got its start in simpler times, when computer users were willing to spend their hard-earned money on a proprietary BBS that offered no Internet access. AOL was successful in enlisting millions of subscribers who wanted to share information with each other. As the industry evolved, individual users began to demand a higher level of service. Previously unheard-of features such as web access and the ability to send e-mail to non-AOL subscribers had to be introduced in order to make the service useful to its clients. Upon adding this functionality, AOL then found itself in the position of being the world's largest Internet Service Provider. They are still in the process of growing into the ability to deliver a level of service that can rival smaller local ISPs, and they have the busy signals and irate customers to prove it. Nothing eases that kind of pain like buying up all the competition in sight.

API - Application Programming Interface. API is a collection of subroutines, usually part of an operating system, that application programs can call upon to perform common tasks. For example, a program might call an API routine to display a window on the screen. APIs reduce the amount of code programmers have to write.

API Extension - An Application Program Interface (API) extension refers to an enhancement or add-on to an existing API. Creative Labs EAX works with Microsoft's DirectSound and DirectSound 3D API making it an open standard.

API (Application Program Interface) a set of tools and/or procedures used for building software applications. For example, operating software such as Windows, allows that an API facilitates the smooth creation of new software by designers to run compatibly with Windows.

APL - A programming language invented in the 1960s using its own characters. APL remains in limited use today.

Apple - Sure, they gave us the computer platform that revolutionised the world of electronic communication, but that contribution dwarfs in comparison with their latest introduction. I am speaking of course of the earth-shattering "Think Different" advertising campaign. Truly the world will never be the same.

Applet - A small program. The term has a special meaning in Java, referring to a program that runs inside a web browser under security restrictions that severely limit what the program can do.

Applet - This typically refers to a module created as a Java program that is designed to run in an environment that supports the Java architecture (such as a web browser). While applets are technically not considered stand-alone programs, they can certainly contain the full functionality of application level software (e.g., word processing, drawing, flashing one's company logo off and on).

AppleTalk - The network system used by Macintosh computers. AppleTalk is a set of network protocols that control network file access, data transmission and other functions. AppleTalk can be implemented on a variety of cable systems, including LocalTalk, Ethernet, and Token Ring.

AppleTalk Phase 2 - AppleTalk Phase 2 protocols provide extensions to the Ethernet networking system that support multiple zones and more devices.

Application - A program that runs on a computer to provide the user with specific functionality. Applications are usually used to create, view, and modify electronic documents. Word processors, image editors, and web browsers are all examples of applications. Even games are considered applications, but it's usually pretty hard to convince your boss that they are essential for productivity.
A program serves some direct purpose for users. A word processor or a game is an application, but an operating system is considered to be system software. Programs that perform system-maintenance functions (such as antivirus checkers or disk defraggers) are often called utilities.

Application Specific Integrated Circuit - A silicon chip hard-coded to run a specific application.

Archie - A database search method which points the Internet user to specific files and FTP sites. Archie can be used to search by subject, title, or keyword.

Architecture - Refers to the layout or design of a hardware device or software program or the combination of the two. Open architecture refers to a system that works easily with devices and applications made by different manufacturers. A closed architecture is often one containing proprietary features and lacking compatibility with other programs and devices.

Archive - An archive is simply a descriptive term for a package of files which appear as one file, often compressed.

ARCnet - (Attached Resource Computer network) A simple and economical type of local-area network (LAN) using token-ring architecture. A token ring system is a group of computers connected in a circular fashion using a special message or password (the token). To communicate with a member of the network, the sender stores the token, attaches a message to it, and allows it to proceed around the ring.

Areal Density - Expressed in billions of bits per square inch (Gbits/inē) of disk surface area, areal density is the product of linear density (bits of information per inch of track) multiplied by track density (tracks per inch). It varies with disk radius. It's important because the areal density directly affects the price per megabyte of a drive.

ARPANET - (Advanced Research Projects Agency Network) The predecessor of the present day Internet. ARPNET was developed in the 1960s by the US Defense Department. ARPANET was designed so that the network would continue to function through peripheral channels even if part of it were destroyed by nuclear attack or sabotage.

Arrow Keys - These are keys on the keyboard which move the cursor around on the screen - they have little arrows on them one for U p arrow, D own arrow, L eft arrow, R ight arrow.

Article - An article is a message posted to the subscribers of a Newsgroup.

Artifact - Graphical flaw caused by the shortcomings of a compression technology. Often manifest as blotchiness in what should be a solid colour.

Artificial Intelligence - ( AI ) A way for game developers to simulate thought processes of sentient life. Artificial intelligence can range from simple movement and attack patterns to simulated lives, complete with eating, movement, and action/reaction modes.

ASCII - (American Standard Code for Information Interchange) - A method of encoding text as binary values. The ASCII coding system contains 256 combinations of 7 bit or 8 bit binary numbers to represent every possible keystroke.
World-wide standard for the codes used by computers to represent letters, numbers, punctuation, etc. Pronounced ASK-EE It is generally referred to as a plain text file. Nothing fancy! Just like typing on a typewriter. A lot of word processors use ASCII text as their standard.

ASIC - Application Specific Integrated Circuit. Pronounced "a-sick." A custom silicon chip designed for a specific application.

ASP - "Active Server Page" A technology for creating web pages that are to contain dynamically-generated elements. Using ASP, a developer can infuse pages with specific programming commands that are executed by the web server and converted into regular old HTML before being sent down to the browser. In contrast to HTML, which is essentially nothing more than a mark-up language for web page layout, ASP is capable of executing a wide variety of genuinely cool functions, like customising page content based on the user's profile, retrieving information from a database, and flashing the current date and time at the top of every page (okay, maybe that last one isn't all that cool). One of the biggest advantages of the ASP delivery model is that it makes no additional demands of the end user in order to work properly. Since all the processing is done on the server and the resulting content is delivered in the form of ordinary web pages, all the browser has to interpret is good old friendly HTML.

ASP Server - Active Server Pages. A Microsoft standard for building web based applications. ASP files can combine HTML scripting - such as JavaScript, VBScript, and components written in any language.

Aspect Ratio - The relation between a display area's width and height. For example, in a traditional 4:3 aspect ratio, the display is defined by four horizontal-length units for every three vertical-length units. In a 16:10 aspect ratio, the width is elongated for a much more pronounced rectangle. It's important to note that typical monitor resolutions - 640x480 through 1600x1200 - all employ a 4:3 aspect ratio.

ASPI - Advanced SCSI Programmer's Interface. It defines a set of software primitives (command) and data structures or an application to use when communicating with SCSI host adapters to be SCSI host adapter-independent.

Assembler - A program that translates assembly language into machine language.

Assembly Language - Programming language that is one step more complex than machine language which is the lowest level programming language.

Assicons - A funny variation on smileys and emoticons.

Associate - To designate that a particular file always be opened with a specific program. Some files may only be opened with specific software while the user may be able to choose one of several applications when opening certain files.

Asynchronous - Operations that do not require the clocks of communicating devices to be co-ordinated.

ATA - Acronym for AT Attachment. A hard driver with an integrated controller. There are multiple levels of ATA standards including the base-level 16-bit IDE, ATA-2 (Enhanced IDE) and Ultra ATA. Ultra ATA/66, a new spec doubling the throughput of the Ultra ATA controller to 66 MB/sec, is expected to be integrated into PCs in early 1999.

ATAPI - ATA Packet Interface. Defines a set of commands supported through the ATA-2 interface for peripherals other than hard drives, such as CD-ROM, DVD-ROM, and tape drives.

Athlon - At the time of writing this is the most advanced processor available for the personal computer. The AMD processor is the next generation, after the Duron. The CPU features, 200 MHz bus speed and 384 KB of on die level 1 and level 2 cache. (Note not all Athlon processors support on die cache). The Athlon also adds 24 more commands to the 3D Now technology used by AMD to open up performance bottlenecks in the 3D graphics pipeline between the processor and a system's graphics card.

ATM - An acronym for Asynchronous Transfer Mode. A method of transmitting bytes across communications links.

Attachment - A file included with mail. When one is communicating via e-mail, it is quite common to include a data file along with the message. This file is called an "attachment." While e-mail was not originally designed to allow for the delivery of elements of data larger than the basic text message, it is becoming more and more common for incoming messages to carry attached files. In fact, the e-mail message itself may consist only of a prompt for the recipient to review the attached file, such as "Hey man, check out this cool JPEG image that I attached!"

Attributes - Refers to the properties of a particular operating system. In Windows the Attrib or Properties command, found under File, in the menu bar displays these.

ATX - A motherboard formfactor that's smaller than AT, it's a standard configuration definition for most modern full-size desktop and tower PCs. Subsets of this include NLX, LPX, and MicroATX. There are numerous differences between the older Baby AT formfactor and ATX, including relocation of the CPU to an area closer to the power supply fan and concentration of I/O ports in one rectangular cluster. How do you know which one you have? Generally, an ATX-type machine will turn itself off after selecting shut down in Windows 95 or NT.
A recent type of motherboard design primarily notable for its "soft power" switch that allows the computer to be shut down and (apparently) turned off by using the shutdown command on the Windows start menu. ATX motherboards are currently the most popular design for Slot 1 and Socket 7 type processors. An ATX motherboard requires a case with an ATX power supply.

AU Format - UNIX sound file format.

AUI Connector Port - The Attachment Unit Interface (AUI) is a DB-15 connector that connects to a transceiver (usually a small box) on cable systems such as thick Ethernet, twisted-pair, or fiber-optic cable systems. Ethernet cards sometimes have these ports in addition to RJ45 and coax cable connectors.

Aureal 3D - (A3D) A proprietary API for handling 3D positional sounds and doppler effects. Using algorithms developed for NASA, A3D simulates 3D positional sounds on two speakers. A3D will support four or more speakers, but is epitomised for two.

Author Ability - The ability to design, develop, or produce software.

Auto Detection - A co-operative mechanism of the CPU and motherboard that identifies proper factory default settings. After auto-detecting the CPU, the motherboard can set variables such as voltage, and shut down systems that have been set beyond certain parameters.

Auto Texture Compression - A video card's ability to automatically compress texture data on-the-fly, without user intervention. This shrinks the data size down, thus allowing more and higher-resolution textures to pass through the data path at a given time.

Avatar - A digital animated character used to represent your virtual position in chat rooms. An avatar may be a cartoon character such as a cat, flower, choo choo train, etc. In cyberspace, the user is represented by such a character.

Average Seek Time - The average time it takes for the read/write head to move to a specific location. To compute the average seek time, divide the time it takes to complete a large number of random seeks by the number of seeks performed.

AVI - "Audio Video Interleave" AVI is the file extension and therefore the common nickname for a "Video for Windows" file. This characteristically confusing acronym represents the digital video file format offered by Microsoft for use in its operating systems. If it stands for "Video for Windows" then why didn't they select ".VFW"? Perhaps this extension was already in use by the "Veterans of Foreign Wars" but only Microsoft knows the answer for sure.

AWK - A programming language, developed in the 1970s, used for scanning and manipulating text files. AWK is an acronym for the last names of the developers of the language, A.V. Aho, P.J. Weinberger, and B.W. Kerningham.