0-9 A B C D E F G H I J K L M N O P Q R S T U V W XYZ

PREVIOUS PAGE         Return to ANSDIT

data administrator.

digital-to-analog converter.

D/A converter:
Synonym for digital-to-analog converter.

Alternate spelling of demon.

daisy chain:
A configuration of multiple devices where each successive device is connected to a previous one.

daisywheel printer:
An impact printer in which the type slugs are mounted at the ends of spring fingers that are attached to a central hub as spokes.

database administration language.

direct access storage device.

Any representation subject to interpretation (such as through analysis or pattern matching) or to which meaning may be assigned, such as by applying social conventions or special agreed upon codes. Data can be processed by humans or by automatic means. (Figure 16 - Interrelationships of data).

data acquisition:
The process of collecting and entering data.

data administration:
The performance of functions such as specifying, acquiring, providing, and maintaining the data of an organization. Contrast with database administration.

data administrator (DA):
A person or group of persons who are responsible for data administration.

data aggregate:
An occurrence of a collection of data items.

data analysis:
A systematic investigation of the data and their flow in a real or planned system.

data attribute:
A predefined characteristic of a data type, data object, module, or some other language construct. For example, a real type may have the data attribute PRECISION with the data values SINGLE or DOUBLE. A task may have the data attribute TERMINATED that yields TRUE if the task is terminated, and FALSE otherwise.

data authentication:
A process used to verify data integrity; for example, verification that data received are identical to data sent, verification that a program is not infected by a virus. Data authentication is not to be confused with authentication.

data bank:
A set of data related to a given subject and organized in such a way that it can be consulted by subscribers.

A collection of data organized according to a conceptual structure describing the characteristics of these data and the relationships among them, supporting one or more application areas.

database administration:
The performance of the functions of defining, organizing, managing, controlling, and protecting all data of a database. The data protected also include metadata and the representation of other descriptions of the database. Contrast with data administration.

database administration language (DAL):
A database language for database administration.

database administrator (DBA):
A person or group of persons who are responsible for database administration.

database file organization:
The arrangement of data in a storage device and implementation of an access method that are in accordance with the data structures of files and of their records and that provide for these records to be part of a database.

database handler:
The component of a database management system that interprets the database calls, and that coordinates and executes the corresponding database accesses.

database language:
A language used to support activities such as creation, modeling, implementation, description, use, and management of databases. For example, a data manipulation language, a data definition language.

database machine:
A computer specifically designed for database applications and possibly implementations.

database management system (DBMS):
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, make a backup, recover, validate, secure, and monitor the database.

database schema:
(1) The set of statements, expressed in a data definition language, that provides a complete description of a database and that includes the names and definitions of all the data elements and their associated attributes. (2) A set of various schemas, each of which has the following properties:
  1. it pertains to a specific level of consideration of a particular universe of discourse or entity world and to the relevant aspects of an appropriate database;
  2. it defines the representation forms for the consistent collection of those sentences of the information base relevant to its respective level of consideration, and it includes the manipulation aspects of these forms.

database subschema:
A part of a database schema for one or more applications.

database utility:
A program for installing, exploiting, or maintaining a database as a whole; for example, programs for loading, unloading, recovery, restructuring, consistency checking, or statistics.

data breakpoint:
A breakpoint that depends upon access to a specific data object.

data bus:
A bus used to communicate data to and from a processing unit or a storage device.

data check:
An operation used to verify data quality or data integrity.

data circuit:
In data communications, a pair of associated transmission channels that provides a means of two-way data transmission. Between data switching exchanges, the data circuit may or may not include data-circuit terminating equipment (DCE), depending on the type of interfaceused at the data switching exchange. Between a data station and a data switching exchange or data concentrator, the data circuit includes the DCE at the data station end, and may include equipment similar to a DCE at the data switching exchange or data concentrator location. (Figure 18 - Half of a data link).

data-circuit terminating equipment (DCE):
In a data station, the equipment that provides the signal conversion and coding between the data terminal equipment (DTE) and the line. The DCE may be separate equipment or an integral part of the DTE or of the intermediate equipment. A DCE may perform other functions that are usually performed at the network end of the line. (Figure 18 - Half of a data link).

data circuit transparency:
The capability of a data circuit to transfer all data without changing the data content or data structure.

data clock:
A clock for data detection and data recording.

data code:
Deprecated synonym for code element.

data code set:
Deprecated synonym for code-element set.

data collection:
The process of bringing data together from one or more points for use in a computer. For example, to collect transactions generated at branch offices by a data network for use at a computer center.

data collection station:
Synonym for data input station.

data communication:
The transfer of data among functional units according to sets of rules governing data data transmission and the coordination of the exchange.

data concentrator:
A functional unit that allows a common transmission medium to serve more data sources than there are transmission channels available. The number of active data sources at a given instant cannot be greater than the number of transmission channels.

data converter:
A functional unit that transforms data from one representation to a different, but equivalent, representation.

data corruption:
An accidental or intentional violation of data integrity.

data coupling:
Coupling in which some or all data shared between two modules are passed through a parameter set.

data definition:
The process or product of creating a schema by identifying and describing data elements and their relationships that make up the database structure.

data definition language (DDL):
A database language for describing data and data structures in a database. Synonymous with data description language.

data density:
The number of characters stored per unit of length, area, or volume. The data density is generally expressed in characters per millimeter (cpmm) or characters per radian (cprad). On disks, the total storage capacity of the disk, recorded on one or both sides, is generally specified rather than the data density.

data description:
A formalized description of a data element and of the data structures in which its name and its words occur.

data description language (DDL):
Synonym for data definition language.

data dictionary:
(1) A database or file that provides definitions for data entities. Synonymous with data element dictionary. (2) Deprecated synonym for data dictionary/directory.

data dictionary/directory:
An inventory of data resources that controls the totality of data entities within an application. It is the repository of all descriptive information about each data entity.

data dictionary system:
A software system for defining, creating, updating, and using data dictionaries.

data directory:
A database or file that identifies data location and ownership.

data directory system:
A software system for defining, creating, updating, and using data directories.

data division:
In COBOL, the declarative part of a program.

Synonym for dump.

data element:
(1) In organization of data, a unit of data that is considered in context to be indivisible; for example, the data element "age of a person" with values consisting of all combinations of 3 decimal digits. (2) In database usage, an identifier of an entity or of an attribute. (3) A named relationship, viewed as an elementary unit, established between objects of the universe of discourse and words representing them.

data element dictionary:
Synonym for data dictionary.

Data Encryption Standard (DES):
The National Institute of Standards and Technology (NIST) Data Encryption Standard, adopted by the U.S. government as Federal Information Processing Standard (FIPS), which allows only hardware implementations of the U.S. Government official data encryption algorithm.

data entity:
An instance of an entity type.

data entry:
The process of putting data onto a machine-readable medium. For example, to enter data to a payroll file on a floppy disk from a terminal.

data exception:
An exception that occurs when a program attempts to use or access data improperly.

data flow:
The movement of data through the active parts of a data processing system in the course of the performance of specific work.

data flowchart:
Synonym for data flow diagram.

data flow diagram:
A diagram that depicts data sources, data sinks, data storage, and processes performed on data as nodes, and logical flow of data as links between the nodes. For one kind of data flow diagram see Figure 17 - Example of a data flow diagram. Synonymous with data flowchart, data flow graph.

data flow graph:
Synonym for data flow diagram.

data flow trace:
Synonym for variable trace.

data glove:
A device worn by a participant in a virtual world that may provide input, output, or both.

In packet switching, a packet, independent of other packets, that carries information sufficient for routing from the originating data terminal equipment (DTE) to the destination DTE, without relying on earlier exchanges bewteen the DTEs and the network.

datagram service:
In packet switching, a service that routes a datagram to the destination identified in its address field without reference by the network to any other datagram. Datagrams may be delivered to a destination address in a different order from that in which they were entered in the network.

data independence:
(1) The organization, storage or retrieval of data or programs in a way not dependent upon the manner specified in user programs. (2) The property of a database management system that allows for application programs to be independent of changes in the data structure.

data input station:
A user terminal primarily designed for entering data into a computer. Synonymous with data collection station.

data integrity:
The property of data that has not been accidentally or maliciously modified in processing, transmission, or storage.

data inventory:
In an information processing system, a list identifying all the data and their characteristics, including interdependencies.

data item:
A named component of a data structure.

data link:
(1) A logical or physical path that supports data transfer. (2) In data communications, those parts of two data terminal equipments that are controlled by a protocol along with the interconnecting data circuit, which together enable data transfer. (Figure 18 - Half of a data link).

data link escape character (DLE):
A transmission control character that changes the meaning of a limited number of contiguously following characters or coded representations.

data link layer:
In OSI, the layer that provides services to transfer data between network layer entities, usually in adjacent nodes. The data link layer detects and possibly corrects errors that may occur in the physical layer. (Figure 39 - Example of a protocol structure for a LAN). (Figure 47 - The Open Systems Interconnection Reference Model).

data management:
In a data processing system, the functions that provide access to data, perform or monitor the storage of data, and control input/output operations.

data manipulation language (DML):
A database language, supported by a database management system, used to access a database for operations such as creating, retrieving, reading, writing, and deleting data. These operations may be specified in the form of procedures (procedural data manipulation language) or in the form of logical expressions (descriptive data manipulation language.)

data manipulation rule:
A prescription for manipulating data objects as instances of a certain data type according to the permissible operations upon data of this data type.

data medium:
Any medium in or on which data may be represented, recorded, transmitted, or presented, or from which data may be retrieved; for example: magnetic tape, floppy disk, CD-ROM, random access memory. Such media may be volatile, however some applications, such as those requiring record retention, may require non-volatile media.

data medium protection device:
A movable or removable device that prohibits writing to or erasing of a data medium.

data mining:
The processing of data with the intent of extracting previously undiscovered patterns and meaningful information.

data model:
A description of the organization of data in a manner that reflects the information structure of an application or an enterprise.

data modeling facility (DMF):
Software for the implementation of data models. For example, SQL provides a data modeling facility for relational databases.

data module:
A removable and hermetically sealed disk pack that incorporates a read/write assembly and magnetic disks.

data multiplexer:
Synonym for multiplexer.

data network:
A network in which data circuits and possibly switching facilities enable data communication among data terminal equipments. (Figure 43 - Network topologies).

data object:
(1) In a database, discrete data, considered as a unit, representing an instance of a data structure that is known or assumed to be known, that have an identifier and that occupy one or more storage locations. (2) In programming languages, an element of a data structure such as a file, an array, or an operand, that is needed for the execution of programs. A data object may be a constant or a variable.

data origin authentication:
The corroboration that the source of data is as claimed.

Next Page