The Computer Folks Glossary

DASD (direct access storage device)	On a mainframe computer, a divice that can directly access data.
Data	Symbols that describe people, events, things and ideas.
Data access software	The interface used to search for information in a database.
Data bus	An electronic pathway or circuit by means of which data travels from one location to another within a computer.
Data communications	The process of transmitting and receiving data in an orderly way.
Data compression	Means of condensing data so that it requires fewer bytes of storage space.
Data dictionary	A tool used by systems analysts to document detailed descriptions of the data that flows through an information system and the data that is stored by that system.
Data file	A file containing words, numbers, and/or pictures that the user can view, edit, save, send, and/or print.
Data flow diagram (DFD)	A diagram that illustrates how data moves through an information system.
Data flow symbol	On a DFD, a line with an arrow on the end, which indicates the directions in which data flows.
Data independence	The seperation of data from the programs that manipulate the data.
Data item	The data contained in a field in a data file.
Data lines	The wire in the data bus that carry the signals that represent data.
Data management	The tasks associated with maintaining and accessing data stored in data files.
Data management enviroment	Software or programs used to designed databases and manage data.
Data management software	Computer programs that help the user store, find, update, organize and report information.
Data mining	Analyzing data to discover patterns and relationships that are important to dicision making.
Data model	A description of the way that data is stored in a database.
Data modul	A converter box, provided by a cellular phone company, that can be used to connect a standard modem to a cellular phone.
Data redundancy	Repetition of data within a database.
Data representation	The form in which information is conceived, manipulated, and recorded.
Data security	Techniques that provide protection for data.
Data store symbol	In a DFD, an open-ended rectangle, which represents data at rest, such as data stored in a file on a hard disk.
Data type	An indicator of the way in which data should be represented on disk and in RAM; used to specify the type of data that can be entered into a field in a data file.
Data warehousing	Collecting vast amounts of data.
Database	A collection of information stored on one or more computers, usually consisting of a variety of different record types treated as a single unit.
Database administrator	A person who supervises database design, development, testing, and maintenance.
Database file	A data file that is organized in a uniform format (also called a structured data file).
Database managment system (DBMS)	Application software that assists the user in manipulating, storing, and maintaining database files.
Database report	Formatted output of some or all the data from a database.
Database software	Computer programs that provide tools for combining and manipulating information stored in a database.
Data-grade cables	Types of cables suitable for data transmission, such as Category 5 UTP or STP cable.
Date data type	A data type that indicates that the data in a field represents a date.
DBMS client software	DBMS software that runs on a workstation on a network, allowing individual workstations to perform data sorts and reports.
DBMS server software	DBMS software that runs on a network server and processes requests for data searches, sorts, and reports from DBMS client software running on individual workstations.
Debugging	The process of testing a section of code and correcting errors.
Decision model	A numerical representation of a realistic situation, such as a cach flow model of a business.
Decision query	A question or set of instructions that describes the data that needs to be gathered in order to make a decision.
Decision support system (DSS)	A system that allows users to manipulate data directly, to incorporate data from external sources, and to create data models or "what-if" scenarios.
Declaritive language	A computer language that lets a programmer write a program by specifying a set of statements and rules that define the conditions for resolving a problem.
Decoding	The conversion of an encoded message back into a form readable by a human being.
Decompressing	The process of expanding compressed data files (also called uncompressing, extracting, and expanding).
Dedicated file server	A file server devoted solely to the task of distributing resources to workstations.
Dedicated line	A permanent telecommunications connection between two locations (also called a leased line).
Default drive	The drive that a computer system will attempt to read from or write to unless an alternate drive is specified.
Defragmentation utility	A tool used to rearrange the files on a disk so that they are stored in contiguous clusters.
Delete	In computer file management, a command used to eliminate a file saved on a disk.
Demodulation	The process of changing a received signal back to its original state (for example, when a modem changes an audio signal back to a digital pulse).
Desktop metaphor	A graphical interface in which the icons resemble items commonly found in an office (file cabinet icon for storage, sheet of paper icon for document, etc.).
Desktop microcomputer	A computer that is built around a single microprocessor chip and is small enough to fit on a desk.
Desktop publishing software	Computer programs that combine graphics and wordprocessing tools to allow the user to create documents.
Detail report	An organized list generated by a management information system.
Device driver	The software that provides the computer with the means to control a peripheral device.
Device failure	A problem with a mechanical device, such as a disk drive.
Dialog box	A type of on-screen display, in the form of a window, that provides options associated with a command.
Dial-up connection	A connection that uses a phone line to establish a temporary Internet connection.
Differential backup	A copy of all the files that have changed since the last full backup of a disk.
Digital certificate	A security method that identifies the author of an ActiveX control.
Digital device	A device that works with discrete numbers or digits.
Digitized sound files	Sound recordings that have been converted into a form that can be stored on a computer disk.
Digitizing	The process of converting videos or continouus sound into a format that can be stored on a computer disk.
Direct access	The ability of a drive to move to any sector of a disk (also called random access).
Direct conversion	The simultaneous deactivation of an old computer system and activation of a new one.
Direct satellite service (DDS)	A service that uses a geosynchronous or low-earth orbit satellite to send television, voice, or computer data directly to satellite dishes owned by individuals.
Directory	A list of files contained on a computer disk.
Discussion group	Online communications involving multiple participants sharing views on a specific issue or topic.
Disk cache	Part of RAM used to temporarily hold information read from a disk, speeding up processing.
Disk compression	A type of data compression that shrinks files and places them in a special volume on the hard disk.
Disk density	The size of the magnetic particles on the disk surface.
Disk jacket	A rigid plastic covering that protects a floppy disk.
Disk liner	A component of the floppy disk that removes dirt and dust from the disk surface.
Disk pack	A group of 6 to 20 hard disk used for storage on many mainframe computer systems.
Disk volume	A disk or an area of a disk that has a unique name and is treated as a seperate disk.
Diskette	Another term for a floppy disk.
Distribution disk	Floppy disks on which computer software supplied to users.
Dithering	A means of reducing the size of a graphics file by reducing the number of colors. Dithering uses patterns composed of two or more colors to produce the illusion of additional colors and shading.
Docking station	An expansion bus into which the user can plug a notebook computer.
Document production software	Computer programs that assist the user in composing , editing , designing, and printing documents.
Document template	A preformatted document into which the user types text.
Document wizards	Tools that take the user step-by-step through the process of entering text in a wide variety of documents.
Documentation	A permanent record that explains how a computer program works.
Document-centric model	A method of using files in which the user chooses the document, and the computer automatically starts the appropriate application program.
Domain name	An identifying name by which host computers on the Internet are familiarly known.
DOS	Disk Operating System
DOS prompt	A symbol indicating that DOS is ready to accept a command.
Dot matrix printer	A printer that creates characters and graphics by striking an inked ribbon with small wires called "pins," generating a fine pattern of dots.
Dot pitch	A measure of image clarity.
Double-density (DD) disk	A type of floppy disk that increased the density of data that could be stored to 360 KB, which was twice the density of previous generation of disks.
Double-sided disk (DS)	A floppy disk that stores data on both the top and bottom sides of the disk.
Downloaded	The process of transferring a copy of a file from a remote computer to another computer's disk drive.
Downstream	In direct satellite service terminology, the direction in which DirecPC satellites transmit, from the satellite functioning.
Downtime	Time during which a computer system is not functioning.
Downwardly compatible	In reference to operating systems, able to use application software designed for earlier versions of the operating system, but not those designed for later versions.
Drive hub	The component of the floppy disk that the disk drive engages in order to rotate the disk.
Drive spindle	The component of the hard drive that supports one or more hard disk platters.
Drop-down list	A list of options that is displayed when the user clicks an arrow button.
DSU (data service unit)	A device on a computer that places data in the proper format for transmission.
Dual-pipeline architecture	A type of micro-processor chip design in which the clip can execute two instructions at one time.
Duplex communication	Also called full-duplex communication, a communications technique that allows the user to simultaneously send and receive messages.