Glossary
prepared for
The Institute on Learning Technology
part of the
Spring 2001
This conversation also is available from the
Learning Through Technology web site,
Glossary
This glossary contains both common and less-common computer technical terms. The sources used are listed on the bottom of this page. When a technical term has a common acronym, both the acronym and the unabbreviated version are listed separately in this glossary (e.g., both "central processing unit" and "CPU" are given).
A
absolute path name - The tree structure which provides the exact address of a file or directory without referring to some other unnamed directory. The absolute path name contains a drive or protocol followed by directories or domains, followed by subdirectories if needed, followed by the file name each part separated by a slash or double slash. For example, a file on a hard drive may have a path name of c://documents/personal/shoppinglist, while a file located on a server to be accessed via the Internet may have an absolute path name of (See also directory path name and path. Compare to relative path name.)
active matrix screen - A type of LCD (liquid crystal display) screen found on portable computers where each pixel has its own unique circuit. The advantage of this is that the screen can be refreshed at a faster rate and other nearby pixels on the screen are not accidentally activated.
active window - The window that the mouse's cursor can affect.
additive color system - A system where colors are created by combining the primary colors together. (See also RGB.)
address - Similar to street addresses, computer addresses identify information's storage location on a computer or identify a node on a network.
alias - 1. The jagged edge found on pixel-based graphical images. 2. In Macintosh systems, a small file that points to another file (usually an application). The alias is similar to the shortcut used on PCs employing Windows.
alpha testing - A software developer's initial release of a program to test for bugs and to receive feedback. Typically, the alpha test has a large number of errors in it. (See Beta testing)
American National Standards Institute - ANSI. An organization that reviews and approves standards in the electronics industry to assist manufacturer in making their electronic products compatible with one another. ANSI is the US representative to ISO.
American Standard Code for Information Interchange - ASCII. The most popular character set used. It employs a 7-bit code for each character and punctuation mark, and consists of the first 128 (0-127) characters of the ANSI character set.
American Standard Code for Information Interchange file - ASCII file. A file that uses the ASCII format. This is one of the simplest formats and can usually be read by any computer or word processor, and is useful in file transfers. It is also commonly called a "text file" or "ASCII text file" and contains very little or no formatting.
analog - A signal that varies or modulates; wired telephone systems use an analog system to covert voice into an electronic signal. (See also Digital.)
ANSI - American National Standards Institute. An organization that reviews and approves standards in the electronics industry to assist manufacturer in making their electronic products compatible with one another. ANSI is the US representative to ISO.
anti-aliasing - A process of interpolation that smoothes the step-stairs of images. The process usually involves adding different hues next to the step-stair, rough-edged pixels to give it a smooth appearance.
applet - A program that is typically designed not to be a stand-alone program but rather called upon by another program. Currently, applets are commonly used with browsers such as Netscape and Internet Explorer and are written in Java.
application - A software program that interacts with the operating system, manipulates data files, has an interface with the user, and allows the user to perform a task or complete a job. Common examples include word processing, spreadsheets, databases, and drawing programs.
AppleTalk - A set of communication protocols used to define networking on the AppleShare network on the Macintosh system.
architecture - Typically the components of a computer system (hardware, bus, software, peripherals, etc.) and how they interact with one another.
arrow keys - Sometimes also called direction keys. The keys are usually found together on the key board and have an up, down, left, and right direction.
ASCII - American Standard Code for Information Interchange. The most popular character set used. It employs a 7-bit code for each character and punctuation mark, and consists of the first 128 (0-127) characters of the ANSI character set.
ASCII file - A file that uses the ASCII format. This is one of the simplest formats and can usually be read by any computer or word processor, and is useful in file transfers. It is also commonly called a "text file" or "ASCII text file" and contains very little or no formatting.
assistive technology - Technology (hardware and software) typically used to help disabled individuals use computers or it provides alternative modes of operation for all users. Examples include text readers (devices that convert text to audio), devices that convert text into Braille, and pointing devices other than the mouse.
asynchronous - A process that does not occur in "real time." In distance education, the learning that typically occurs via email would be asynchronous since there is typically a time delay between when the message is sent and when a reply is received. (See also synchronous.)
attachment - An encapsulated file or image that is placed within another document. Attachments, used with email systems, can be word processing documents, spreadsheets, audio files, or images among others.
B
BASIC - Beginner's All-purpose Symbolic Instruction Code. A simple to use programming language that has gradually lost favor to other languages because of portability issues. The most popular version is now Visual Basic.
Basic Input/Output System - BIOS. A program found on PCs used to connect with input and output devices like the mouse, keyboard, and monitor prior to the loading of the operating system. The program may be part of the CPU as in firmware.
baud/baud rate - Data transmission speed units that approximately equals one bit per second (1 bps).
BBS - Bulletin Board System. An electronic bulletin board in which a computer server/host used by a group of individuals to share messages, software, or who have a common interest.
Bulletin Board System - BBS. An electronic bulletin board in which a computer server/host used by a group of individuals to share messages, software, or who have a common interest.
base-2 numbering - A numbering system based on 2 rather than the commonly used based 10. Numbering in base 2 would be: 0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111, 10000 (these numbers correspond to 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16). The place holders in base-10 are 1's, 10's, 100's, 1000's; in base-2 numbering systems the place holders are 1's, 2's, 4's, 8's, etc. So 1111 means 1 one, 1 two, 1 four, and 1 eight for a total of 15.
Beginner's All-purpose Symbolic Instruction Code - BASIC. A simple to use programming language that has gradually lost favor to other languages because of portability issues. The most popular version is now Visual Basic.
beta/beta testing - A program's second-release to discover bugs and receive feedback. Beta versions may be made public or may be released to a small number of designated "beta-testers." Typically, beta versions have fewer bugs than alpha versions but more bugs than a regular release.
binary - The base-2 numbering system which computers use to represent switches of either being "on" or "off" (or 1 and 0).
binary digit - bit. The smallest unit used by computers (either a 1 or 0).
bit - binary digit. The smallest unit used by computers (either a 1 or 0).
bitmap - An arrangement or set of pixels using binary values (1 or 0 for black and white images).
byte - Eight bits of data representing a number between 0 and 255 (in the base-2 numbering system, a number between 0 and 11111111). Each byte often represents a single character in texts.
BIOS - Basic Input/Output System. A program found on PCs used to connect with input and output devices like the mouse, keyboard, and monitor prior to the loading of the operating system. The program may be part of the CPU as in firmware.
bit-mapped graphics - An image that uses a bitmap format: an array or matrix of pixels. Often, bit-mapped graphics are black and white images.
bps - 1 bits per second. Usually used to describe baud rates.
buffer - Usually a temporary allocation of system memory often used by programs as a way to access and alter content.
bandwidth - The amount or capacity of data that can be transmitted over a unit of time. Usually described in bits per second (bps) for digital transfers and cycles per seconds (Hertz, Hz) in analog systems.
broadband - A network that carriers multiple networks using different frequencies. The networks can work simultaneously without interfering with one another's transmissions.
bug - A hardware or software error that causes inconsistent performance.
batch processing - The scheduling of a series of tasks to be completed; for example, a series of print job orders are received and carried out in a prioritized order.
boot - Placing the system software into the system memory and starting it up (i.e., often used to mean starting the computer).
browser - An application used to view and interact with the world wide web and interpret HTML code. Also called a web browser. The two most common browsers are Netscape Communicator, Microsoft Internet Explorer.
C
C - A popular software programming language that is highly portable.
C++ - The object-oriented version of the C programming language. It is more complicated but still portable.
cache - High speed storage used as a transfer point for frequently used data between the CPU and the hard disk or RAM memory. Cache memory is used because it improves computer performance making it faster. Cache memory is usually either fast RAM memory or a specific region of the hard disk set aside for this specific use.
CAD - computer-aided design. Using computers to help design, draw, and analyze the production of industrial or electronic components.
capture - To save or record some data stream (video, graphical, textual).
card - A processor that can be added to an expansion slot located on the mother board of a PC. The card can be a video accelerator card (a processor dedicated to processing video) or it can function in a variety of other capacities. Also called an expansion card.
cascade windows - Overlapping windows on the desktop of a PC with Windows or Macintosh computer so that only the title bar and a small portion of the inactive windows are visible. See also tiled windows.
cascading menu - Drop down menus with submenus.
cathode ray tube - CRT. The video/imaging tube of most TVs and computer monitors. The CRT contains phosphors (chemicals that glow when excited) that are chemically excited by an electron beam.
CD-ROM - compact disc read-only memory. An optical storage medium that can hold about 600 MB of data and is accessed with lasers.
central processing unit - CPU. The central processing unit contains the chip or main processor of a personal computer. It performs the basic tasks and functions of the computer, and is often called the "brains" of the computer. The central processing unit may also refer to the housing or motherboard that contains the chip.
character set - A set of numbers, letters, and special characters that have some design characteristic in common. For examples, the ASCII character set.
checkbox - Usually a small box that can be toggled either "on" of "off." When clicked, an "x" or checkmark appears signifying an "on" option.
chip - An integrated circuit usually made of silicon that contains a very large number of electronic components. The chip is the "brains" of the computer.
Chooser - A system component of Macintosh computers allowing the user to select between printers, servers, and other networked devices.
CHRP - common hardware reference platform. A hardware architecture that uses the PowerPC CPU and a PCI bus. The CHRP is found in Macintosh computers but supports other operating systems. (Also called the PowerPC Platform.)
CISC - complex instruction set computing. A chip architecture with a variety of simple tasks hard-coded into the chip. Older chips such as the Motorola 680x0 and Intel 80x86 had a CISC architecture; newer chips use the RISC architecture.
CLI - command-line interface. Typically refers to an operating system that is controlled by typing in command lines. A primary example of CLI is MS-DOS where a command line such as, c://format a:, is required to format a disk in drive “a.” Most desktop computers use a graphical user interface (GUI) instead (Unix is a CLI-based system).
click - The process of placing the mouse cursor over an object on the desktop and pressing down on the mouse button and releasing.
client - A computer that is accessing another remote computer (i.e., a server) and retrieving data in some form.
clipboard - A temporary storage of information (text, image), etc.) to facilitate the transfer of this data from one document to another or from one application to another. The clipboard's content is removed when the computer is turned off. It can be accessed in Macintosh computers under the desktop menu item Edit/Show clipboard or Clipboard Viewer in Windows-based computer.
CMYK - cyan, magenta, yellow, black. A color description that defines colors with a subtractive color system starting with white and removing percentages of cyan, magenta, or yellow. CMYK is used to define colors on printers.
coaxial cable - A wire well suited to network transmissions. It contains a solid core wire surrounded by insulation surround be another conducting braided band. The wire can carry high bandwidths with little interference. There are different types of coaxial cables including thin coaxial (10Base-2), thick coaxial (10Base-5), and twisted pair (10Base-T) cables.
COBOL - common business-oriented language. One of the older programming languages aimed at business users that is portable but also longer (i.e., less efficient).
command-line interface - CLI. Typically refers to an operating system that is controlled by typing in command lines. A primary example of CLI is MS-DOS where a command line such as, c://format a:, is required to format a disk in drive “a.” Most desktop computers use a graphical user interface (GUI) instead (Unix is a CLI-based system).
comment - In programming languages, a comment is information placed there by the programmer but ignored by the compiler. In HTML, a "<!--" starts the comments and a "-->" ends the comment.
common business-oriented language - COBOL. One of the older programming languages aimed at business users that is portable but also longer (i.e., less efficient).
common hardware reference platform - CHRP. A hardware architecture that uses the PowerPC CPU and a PCI bus. The common hardware reference platform is found in Macintosh computers but supports other operating systems. (Also called the PowerPC Platform.)
compact disc read-only memory - CD-ROM. An optical storage medium that can hold about 600 MB of data and is accessed with lasers.
compiler - A application that takes source code and converts it into machine code that can be executed by the computer.
complex instruction set computing - CISC. A chip architecture with a variety of simple tasks hard-coded into the chip. Older chips such as the Motorola 680x0 and Intel 80x86 had a complex instruction set computing architecture; newer chips use the RISC architecture.
compressed video - A digital video segment that has been reduced in size by using computer algorithms. The compressed version usually has a lower resolution than the uncompressed version. The better the compression algorithm, the greater the reduction in size without the corresponding reduction in resolution.
compression - The process of taking a data object and reducing its size. The tradeoff that occurs is between the loss of resolution versus the reduction in size.
COM port - A connecting location on computers for a serial cable. Serial cables usually have 9 pins and pass data at a slower rate than parallel ports. Serial ports can be used for printers and modems.
computer-aided design - CAD. Using computers to help design, draw, and analyze the production of industrial or electronic components.
cookie - A cookie is a small amount of information written on a client computer (typically your personal computer) from a server and is especially common on the web. The information may include a userID or your previous Internet shopping excursion.
coprocessor - An additional processor that usually has a specific dedicated task such as number crunching or video processing. Coprocessors are attached on small circuit boards called cards and are inserted in expansion slots.