Z94.3 - Computer & Information Systems

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DATA. (1) (ANSI/ISO) A representation of facts, concepts, or instructions in a normalized manner suitable for communication, interpretation, or processing by humans or by automatic means. (2) (ANSI) Any representations such as characters or analog quantities to which meaning is or might be assigned.

DATA BASE. (1) (ANSI/ISO) A collection of interrelated data, often with controlled redundancy, organized according to a schema to serve one or more applications; the data are stored so that they can be used by different programs without concern for the data structure or organization. A common approach is used to add new data and to modify and retrieve existing data.

DATA BASE MANAGEMENT SYSTEM. (DBMS). (1) (ANSI) An integrated set of computer programs that collectively provide all of the capabilities required for centralized management, organization, and control of access to a database that is shared by many users. (2) (ANSI) A computer-based system used to establish, make available, and maintain the integrity of a database, that may be invoked by nonprogrammers or by application programs to define, create, revise, retire, interrogate, and process transactions; and to update, back up, recover, validate, secure, and monitor the database.

DATA BASE MANAGER. A shortened version of data base management system that is commonly used by microcomputer users.

DATA DIRECTORY. (1) (ANSI) An inventory that specifies the source, location, ownership, usage, and destination of all of the data elements that are stored in a database. (2) (ANSI) A subset of a data dictionary/directory that has the functions of (1).

DBMS. (See DATA BASE MANAGEMENT SYSTEM.)

DECISION TABLE. (1) (ANSI/ISO) A table of all contingencies that are to be considered in the description of a problem, together with the actions to be taken for each set of contingencies.

DIGITAL COMPUTER. (ANSI) A computer that consists of one or more associated processing units and peripheral equipment and that is controlled by internally-stored programs. A computer may be a stand-alone unit or may consist of several interconnected units.

DIGITIZE. (ANSI/ISO) To express or represent in a digital form data that are not discrete data, e.g., to obtain a digital representation of the magnitude of a physical quantity from an analog representation of that magnitude.

DIRECT ACCESS. (1) (ANSI/ISO) The capability to obtain data from storage devices or to enter data into a storage device in a sequence independent of their relative position, by means of addresses that indicate the physical location of the data. (2) (ANSI) Pertaining to the organization and access method that must be used for a storage structure in which locations of records are determined by their keys, without reference to an index or to other records that may have been previously accessed.

DIRECTORY. (See DATA DIRECTORY.)

DISK. (See DISKETTE, FLEXIBLE DISK, MAGNETIC DISK.)

DISK DRIVE. (1) (ANSI/ISO) A mechanism for moving a disk pack or a magnetic disk and controlling its movement. 

DISKETTE. (ANSI/ISO) A flexible magnetic disk enclosed in a protective container. Syn: flexible disk.

DISK OPERATING SYSTEM. The software that controls or manages the basic functions of a computer.

DOCUMENT. (ANSI) A medium and the information recorded on it that generally has permanence and that can be read by humans or machines.

DOS. (See DISK OPERATING SYSTEM.)

DOT MATRIX PRINTER. Syn: matrix printer.

DOUBLE PRECISION. (ANSI/ISO) The use of two computer words to represent a number in accordance with required precision.

DUPLEX TRANSMISSION.   (ANSI/ISO) Data transmission in both directions at the same time.

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