Caching
A process in which frequently accessed data is kept on hand, rather than constantly being from the place where it is stored.

Case-dependent
Software differentiation between upper and lower case characters. Also referred to as case sensitive.

CCD
Charge-coupled device. An integrated, micro-electrical light sensing device built into some image capturing devices.

CD-ROM
Compact Disk, Read-Only Memory. A type of storage device that looks just like an audio CD and stores as much data as a large hard disk (600MB), making it a popular means of distributing fonts, photos, electronic encyclopedias, games, and multimedia offerings. As the name indicates, however, you can't save or change files on a CD-ROM, only read them. Pronounced see-dee rom.

CGI
Common Gateway Interface. A method of running an executable script or program from a Web server. When a client requests a URL pointing to a CGI, the program is run and the results are returned to the client. This enables dynamic web pages and the ability to do database queries and other complex operations across the web

CIE
The "Commission Internationale de l'Eclairage". An organization that has established a number of widely-used color definitions.

Circuit-switched
A type of network connection which establishes a continuous electrical connection between calling and called users for their exclusive use until the connection is released. Ericsson PBX is a circuit-switched network.

Clickable Image
Any image that has instructions embedded in it so that clicking on it initiates some kind of action or result. On a web page, a clickable image is any image that has a URL embedded in it.

Client/server relationship
A client application is one that resides on a user's computer, but sends requests to a remote system to execute a designated procedure using arguments supplied by the user. The computer that initiates the request is the client and the computer responding to the request is the server. Many network services follow a client and server protocol.

Clipboard
An area used to temporarily store cut or copied information. The Clipboard can store text, graphics, objects, and other data. The Clipboard contents are erased when new information is placed on the Clipboard or when the computer is shut down.

Clipping
The conversion of all tones lighter than a specified grey level to white, or darker than a specified grey level to black, causing loss of detail. This also applies to individual channels in a color image.

CMS
Color management system. This ensures color uniformity across input and output devices so that final printed results match originals. The characteristics or profiles of devices are normally established by reference to standard color targets.

CMYK
Cyan, magenta, yellow, and black are the base colors used in printing processes. CMY are the primary colorants of the subtractive color model.

Colorimeter
A light-sensitive device for measuring colors by filtering their red, green, and blue components, as in the human eye. See also spectrophoto-meter.

Color Cast
An overall color imbalance in an image, as if viewed through a colored filter.

COM1, COM2, etc. -
Most serial ports and internal modems on DOS/WIN PCs can be configured to either COM1 or COM2 in order to accommodate the situation where both may exist. The DOS MODE command is used to change the output direction to such serial devices as modems.

Compression
The reduction in size of an image file. See also lossy and non-lossy.

Computer Search Service
Computer Search Service (CSS), a fee-based service, offers access to more than 500 databases, primarily in the sciences and social sciences, from which the Library can create customized bibliographies.

Configuration
1. The components that make up a computer system (which model and what peripherals). 2. The physical arrangement of those components (what's placed and where). 3. The software settings that enable two computer components to talk to each other (as in configuring communications software to work with a modem).

Contone (CT)
An abbreviation for continuous tone. A color or greyscale image format capable of illustrating continuously varying tonal ranges, as opposed to line art.

Cookies
A file sent to a web browser by a web server that is used to record once's activities.

Coprocessor
A chip designed specifically to handle a particular task, such as math calculations or displaying graphics on-screen. A coprocessor is faster at its specialized function than the main processor is, and it relieves the processor of some work. A coprocessor can reside on the motherboard or be part of an expansion card, as with an accelerator.

Coaxial Cable
A type of cable that contains two conductors. The center conductor is surrounded by a layer of insulation, which is then wrapped by a braided-metal conductor and an outer layer of insulation.

CPU
Central Processing Unit; the brains of the computer. The CPU interprets and executes the actual computing tasks.

Crash
A problem (often caused by a bug) that causes a program, or the entire operating system, to unexpectedly stop working.

CREN
Corporation for Research and Educational Networking. This organization was formed in October 1989, when BITNET and CSNET (Computer + Science NETwork) were combined under one administrative authority. CSNET is no longer operational, but CREN still runs BITNET. See BITNET.

Cross-platform
Refers to software (or anything else) that will work on more that one platform (type of computer).

CSUNET
California State University Network. A packet-switched network that connects the 22 campuses of the CSU system.

Cursor
The representation of the mouse on the screen. It may take many different shapes. Example: I-beam, arrow pointer, and hand.

Cyberspace
A term used to refer to the electronic universe of information available through the Internet.