Glossary: D

data

A general term for numbers, letters, and other symbols processed by a computer to produce information.

data bus

An electrical path to transfer data and instructions back and forth between internal memory devices and the processor.

data communications

Transferring data or information between computer-related devices such as electronic mail.

data definition

The process of deciding on the number and characteristics of all the data fields in each record in the early stages of developing a database.

data entry

The process of encoding data into fields to create database records.

data glove

A glove filled with sensors to detect body movement and effect change in the simulated world of VR.

data integrity

The need to insure that information contained in a database is accurate and timely -- that is, free of corruption by input or programming errors.

data processing

A general term that stands for all the logical, arithmetic, and input/output operations that can be performed on data by a computer.

data protection (data security)

A term referring to strategies for protecting databases against illegal access or modification, such as needing a password to access a database.

database

A collection of related files stored electronically that can be edited, joined, sorted, and searched.

database package

Software used to create, maintain, retrieve, and produce reports about information kept in database records.

debugging

The process of correcting errors in a computer program, often helped by error diagnostics from the compiler.

decision box (branch)

One of the fundamental building blocks of flowcharting, offering a choice between alternative directions to continue, analogous to selection in structured programming.

dedicated word processor

A specialized computer typewriter designed only for word processing.

DENDRAL

An early successful expert system for classifying chemical compounds based on their spectrographic characteristics and the rules that govern chemical bonding.

descending sort

Arrangement of sorted data from highest to lowest in sequence.

desktop

The background of a computer screen with a GUIon which icons and windows appear.

desktop publishing

Using software to do page design and computer typesetting with laser printers for publications such as newsletters and magazines.

digital (numeric) data

A term that applies to forms of data that can be expressed in numeric terms and thus can be readily processed by digital computers.

digital signature

A term for a secure transaction code used to encode sensitive personal information sent over a network so that the decoder will know that it is unique to the sender.

digital television

The transmission of television signals in a digital form. Current television is sent out as analog signals, but future television is probably going to be digitally distributed, much like electronic mail and other forms of data communication today.

digitized

A term for information that has been converted into binary digits for computer processing.

digitized video

A process in which a hardware circuit board on a computer accepts input from a TV or VCR and converts the images to digital format at a rate of between 15 and 30 frames a second, capturing full-motion video for the computer screen.

digitizer board

A circuit board for a computer that accepts video input and digitizes it so that it may be seen on the computer screen.

digitizing scanner

A hardware device that converts color or black-and-white images on paper to pixel images so that they may be processed by a computer.

disk drive

The most common form of secondary storage hardware device. A drive can read programs and data stored on diskettes or hard disks and transfer them to internal memory.

diskette

The most common form of secondary storage -- small, inexpensive, and portable -- which records data as magnetized bits that are read by a disk drive.

distance learning

The delivery of educational course materials offsite, formerly through videotape and closed circuit television, now often carried out with shared content resources on the Internet.

dithering

A process used in some color printers and graphics software to adjust the number of dots of different colors within a matrix of eight pixels to produce many shades.

DOS

An abbreviation for Disk Operating System, the popular operating system developed by Microsoft and found on IBM-compatible computers.

dot-matrix printer

An impact printer that prints characters on paper as a series of dots based on grid pattern designs.

downloading

Transferring files from a host computer on a network to remote machines, typically microcomputers.

downsizing

A term for the shrinking size of modern corporations and the subsequent loss of jobs of many workers, including many middle managers.

draw program

A graphics program that provides commands to create regular shapes -- like rectangles -- as objects that can be resized or moved around without affecting other objects.

drill-and-practice educational software

Instructional computer programs that drill students on materials for mastery, such as foreign language grammar exercises.

dynamic

A term applied to spreadsheets to describe their changing whenever new values are introduced, since all relations embodied in the spreadsheet must be reassessed relative to the new data.

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