D

DAA

See designated approving authority (DAA).

DACTLU

In SNA, a command used to end a session on a logical unit.

DACTPU

In SNA, a command used to end a session on a physical unit.

daemon

(1) In the Distributed Computing Environment (DCE), a long-lived process that runs unattended to perform continuous or periodic systemwide functions, such as network control.

(2) In Network File System (NFS), a local task on the client or server that processes both local and remote requests and handles client/server communications. After a daemon performs its function, it returns to its previous state.

daemon configuration file

In the Distributed Computing Environment (DCE), a file containing information on which daemons are configured on the host, including which environment variables are set, the parameters to pass to the process, minimum restart interval, and the time-out period. See daemon.

DAF

See destination address field (DAF).

damaged logical unit of work

The effect on protected resources caused by part of the resources committing and part rolling back.

DAP

See directory access protocol (DAP).

DARPA

See Defense Advanced Research Projects Agency (DARPA).

data area

A system object used to communicate data, such as CL variable values between the programs within a job and between jobs. The system-recognized identifier for the data area is *DTAARA.

data authority

A specific authority to read, add, update, or delete data, to run a program, or to search a library or directory. See also add authority, delete authority, execute authority, read authority, and update authority. Contrast with object authority.

database

(1) A collection of data with a given structure for accepting, storing, and providing, on demand, data for multiple users. (T)

(2) All the data files stored in the system.

database administrator

The user responsible for the design, development, integrity, and maintenance of databases.

database file

One of several types of the system object type *FILE kept in the system that contains descriptions of how input data is to be presented to a program from internal storage and how output data is to be presented to internal storage from a program. See also physical file and logical file.

database management system (DBMS)

A system that has a set of tables describing the data it manages. The DBMS controls the access to the data stored within it. The DBMS also has transaction management and data recovery functions to protect data integrity.

database manager

The part of the OS/2 operating system that supports an SQL relational database.

database reference field

In the Data Description Specifications Design Utility (DSU), a field in a data description specifications (DDS) source file that is created by referring to the description of an existing field in a database file.

data character set

See character set.

data circuit-terminating equipment (DCE)

The equipment installed at the user's premises that provides all the functions required to establish, maintain, and end a connection, and the signal conversion and coding between the data terminal equipment and the line. See also data terminal equipment (DTE) and modem.

data clause

In COBOL, a clause in a data description entry in the Data Division that describes a particular characteristic of a data item.

data code page

In Network File System (NFS), a list of the data name components of the files that are exported to and mounted on the specified NFS client or netgroup.

data communications

The sending and receiving of data between computers, remote devices, or both according to selected protocols.

data compression

The reduction of data volume on the media when performing save operations. See also compaction and compression.

data conversion

(1) The process of changing data from one form of representation to another.

(2) The process of changing from one coded character set identifier (CCSID) to another. A system does data conversion when exchanging data with another system that is using a different CCSID.

data country code (DCC)

A 3-digit code, unique to each country, that specifies the X.21 call format used by a network in its International Data Number to call another station.

data decompression

Reconstruction of data from a compressed format when performing a restore operation. See also decompression.

data definition

(1) In IDDU, information that describes the contents and characteristics of a field, record, or file. See also field definition, file definition, and record format definition.

(2) In the C language, a definition that describes a data object, reserves storage for a data object, and can provide an initial value for a data object. A data definition appears outside a function or at the beginning of a block statement.

data definition language (DDL)

A language for describing data and its relationships in a database. (T)

data description entry

In COBOL, an entry in the Data Division that describes the characteristics of a data item.

data description specifications (DDS)

A description of the user's database or device files that is entered into the system in a fixed form. The description is then used to create files.

Data Description Specifications Design Utility (DSU)

A feature of the CoOperative Development Environment/400 licensed program that helps users develop and create display files, printer files, and database files.

data dictionary

In IDDU, an object for storing field, record format, and file definitions. The system-recognized identifier for the object type is *DTADCT.

data dimension

A major part of the SystemView structure that defines a consistent format for the storage of systems management data using the SystemView data model.

Data Division

In COBOL, one of the four main parts of a COBOL program. The Data Division describes the files to be used in the program and the records contained within the files. It also describes any internal working-storage records that are needed.

data dump

In COBOL, the contents of the data areas used by a program that has failed.

data-encrypting key

In Cryptographic Support, a key used to encrypt data that is not a cryptographic key. Used with the CPHDTA and GENMAC commands.

Data Encryption Algorithm (DEA)

In Cryptographic Support, equivalent to the Data Encryption Standard. Adopted by the American National Standards Institute in 1981.

Data Encryption Standard (DES)

In Cryptographic Support, a cryptographic algorithm designed to encrypt and decrypt data using a 64-bit key as specified in the Federal Information Processing Standard 46, January 15, 1977.

data field instruction

In the OfficeVision program, a text instruction in a shell document that indicates where variable data should be inserted. Variable data for a data field instruction is supplied from a fill-in document, a file, or a query.

data file

(1) A group of related data records organized in a specific order. A data file can be created by the specification of FILETYPE(*DATA) on the create commands. Contrast with source file.

(2) In RJE, a remote job input stream that can contain host system commands and job control language as well as data. Contrast with command file.

data file utility (DFU)

The part of the Application Development ToolSet licensed program that is used to enter, maintain, and display records in a database file.

data flow control layer

In SNA, the layer within a half-session that (a) controls whether the half-session can send or receive, or both send and receive request units (RUs) at the same time, (b) combines related RUs into RU chains, (c) defines the limits of transactions by using the bracket protocol, (d) controls the connection of requests and responses in accordance with control modes specified when the session is started, (e) creates sequence numbers, and (f) associates requests with responses.

datagram

(1) In DCE Remote Procedure Call, a network packet that is independent of all other packets and does not guarantee delivery or sequential order.

(2) The simplest message that MQSeries supports. This type of message does not require a reply.

(3) A unit of data that is sent across a TCP/IP network. A datagram contains both data and header information, such as the IP address of the origin and of the destination.

datagram protocol

In DCE Remote Procedure Call, a datagram-based transport protocol, such as User Datagram Protocol (UDP), that runs over a connectionless transport protocol.

data group

(1) In Business Graphics Utility, a collection of values that identify the comparisons in a chart. For example, the relative size of the slices in a pie chart or the relative height of the bars in a bar chart. See also paired data. Contrast with data value.

(2) In the GDDM function, a collection of data values displayed, for example, as a pie chart or as the plotted points on a line of a line chart. More than one data group may be displayed on a chart.

data hierarchy

In COBOL, the relationship between a group item or record and the group data items and elementary data items that make it up.

data integrity

(1) The condition that exists as long as accidental or intentional destruction, alteration, or loss of data does not occur.

(2) Within the scope of a unit of work, either all changes to the database management systems are completed or none of them are. The set of change operations are considered an integral set.

data interchange

The use of data by systems of different manufacture.

data interchange format (DIF)

In Client Access, a format that presents data in rows and columns.

data item

(1) A unit of information to be processed.

(2) In COBOL, a character or a set of consecutive characters (excluding literals in either case) defined as a unit of data by the COBOL program.

data label

In Business Graphics Utility and the GDDM function, a text string that describes a set of data values. Data labels are used with bar charts, pie charts, and Venn diagrams.

data limit

In the Distributed Computing Environment (DCE), a value that specifies which elements of an array are transmitted during a Remote Procedure Call (RPC).

data line

(1) In Business Graphics Utility, a straight line drawn from either axis that shows the exact data values on the chart.

(2) In the GDDM function, a line drawn parallel to a chart axis, through a specified value along the other axis.

data link

The physical connection (communications lines, modems, controller, work stations, other communications equipment), and the rules (protocols) for sending and receiving data between two or more locations in a data network.

datalink

A field in a database file that contains a link to an object. The link is in the form of a uniform resource locator (URL).

data link connection identifier (DLCI)

The field in a Q.922 frame that is used for frame relay routing. Each DLCI identifies a frame relay virtual circuit.

data link control (DLC)

See high-level data link control (HDLC), synchronous data link control (SDLC), and ISDN data link control (IDLC).

data link control (DLC) layer

In communications, the layer that consists of the link stations that schedule data transfer over a link between two nodes and perform error control for the link. Examples of data link control are SDLC and HDLC.

data-link-escape (DLE) character

A BSC transmission control character used to indicate that the next character is a control character, not a data character.

DataLink File Manager

A system function that maintains the status of objects that are linked to a database file through a datalink.

data link layer

In OSI, the layer that provides the functional and procedural means to establish, maintain, and release data-link connections among network entities, and to transfer data-link service data units.

data link protocol

The rules that govern control of the physical connection for sending and receiving data between two or more locations in a network. Examples of data link protocols include (a) asynchronous, (b) binary synchronous communications (BSC), (c) Ethernet, (d) synchronous data link control (SDLC), (e) token-ring network, and (f) X.25. Contrast with communications line.

data management

The part of the operating system that controls the storing and accessing of data to or from an application program. The data can be on internal storage (for example, database), on external media (diskette, tape, or printer), or on another system.

data mapping

The process of changing characters from one form of representation to another, such as from zoned decimal to packed decimal.

data merge

See data/text merge.

data mode

In data communications, a time during which BSC is sending or receiving characters on the communications line.

data multiplexer

See multiplexer.

data name

In COBOL, a user-defined word that names a data item. When used in the general formats, data name represents a word that cannot be subscripted, indexed, or qualified unless specifically permitted by the rules of that format (see identifier).

data network identification code (DNIC)

A 4-digit code that specifies the X.21 call format used by a network in its International Data Number to call another station. The first three numbers are the data country code, and the last number is the country network identifier. See also data country code (DCC).

data object

(1) A program variable that provides operational and possibly representational characteristics to byte strings in spaces. Contrast with machine object.

(2) An object that conveys information, such as text, graphics, audio, or video.

Dataphone digital service (DDS)

The AT&T line service that allows the customer to transmit data on the line in a digital format.

data pointer

A pointer that provides addressability and scalar representational attributes to a byte string in a space.

data policy

The collection of protocols that governs Phase II negotiations.

data queue

An object that is used to communicate and store data used by several programs in a job or between jobs. The system-recognized identifier is *DTAQ.

data reference line

In the GDDM function, a data line that also acts as a shading boundary for the first data group of a surface chart, histogram, or composite bar chart, or for all the data groups of a multiple bar chart. If no data reference line is present, such data groups are shaded from the horizontal axis.

data server

A device on a local area network (LAN) that provides services, data, or facilities for other devices on the network.

data service unit (DSU)

A device that provides a digital data service interface directly to the data terminal equipment. The DSU provides loop equalization, remote and local testing capabilities, and a standard EIA/CCITT interface.

data stream

All information (data and control commands) sent over a data link usually in a single read or write operation. For example, a data stream is used to send displays and to receive displays from a workstation device.

data structure

(1) An area of storage that defines the layout of the fields, called subfields, within the area. A data structure is program described.

(2) In OSI, the syntactic structure of symbolic expressions and their storage allocation characteristics. (T) In OSI Communications Subsystem, data structures are created by the Abstract Syntax Checker.

(3) In RPG, an area in storage that defines the layout of the fields, called subfields, within the area. A data structure can be either program described or externally described.

data terminal equipment (DTE)

(1) That part of a data link that sends data, receives data, and provides the data communications control function according to protocols.

(2) In OSI, a physical node on a network.

data/text merge

In OfficeVision and Query, the process of combining data from a file or another document (such as names and addresses) with the text of a document (such as a form letter).

data token

In OSI, the token that controls which peer entity has permission to send on a half-duplex connection.

data tower

In AFP Utilities, a set of Intelligent Printer Data Stream commands that represent a data type, such as text, image, graphics, and bar code.

data traffic

In data communications, the quantity of data transmitted past a particular point in a path.

data type

(1) A characteristic used for defining data as numeric or character.

(2) In DB2 UDB for AS/400, an attribute of columns, constants, and host variables.

(3) In the C language, a set of values together with a set of permitted operations. A data type determines the kind of value that a variable can assume or that a function can return.

data types

In OSI, categories of data clearly defined using a data declaration method, such as ASN.1 or Pascal. See also ASN.1 types.

data value

In Business Graphics Utility, a single, numeric data item entered as a value for a horizontal line or vertical line. Contrast with data group.

data warehousing

A set of hardware and software components that can be used to analyze large amounts of data for making effective business decisions. For example, data warehousing can be used to analyze daily sales information, customer orders, products, inventory, and schedules.

date

A three-part value or data type that designates a day, month, and year.

date duration

A decimal number that represents a number of years, months, and days.

date/time value

In DB2 UDB for AS/400, a value of the data type DATE, TIME, or TIMESTAMP.

dB

Decibel; a measure of loudness.

DBCS

See double-byte character set (DBCS).

DBCS code

The hexadecimal code, 2 bytes in length, that identifies a double-byte character.

DBCS conversion

A function of the operating system that allows a display station user to enter alphanumeric data and request that the alphanumeric data be converted to double-byte data.

DBCS conversion dictionary

A table used by the conversion function to map alphanumeric entries to double-byte entries. The system-recognized identifier for the object type is *IGCDCT. See also DBCS number.

DBCS data

In DB2 UDB for AS/400, data that is associated with a double-byte character set.

DBCS-either

Pertaining to a character string that is either SBCS or bracketed DBCS, but not both. Contrast with DBCS-graphic, DBCS-only, and DBCS-open.

DBCS font file

A system-supplied file that holds the 24x24 character images of one of the following groups of commonly used characters: 1) Japanese non-Kanji and basic-Kanji, 2) Korean non-Hangeul/non-Hanja, Hangeul, and a subset of Hanja, 3) Traditional Chinese non-Chinese and a subset of primary Chinese characters, or 4) all IBM-defined Simplified Chinese characters.

DBCS font table

A system-supplied table that holds either 24x24 or 32x32 pel character images of a double-byte character set. A Japanese 24x24 DBCS font table holds Japanese extended Kanji and user-defined characters. A Korean 24x24 DBCS font table holds a subset of Hanja and user-defined characters. A Traditional Chinese 24x24 DBCS font table holds a subset of primary Traditional Chinese, all secondary Chinese, and user-defined characters. A Simplified Chinese 24x24 DBCS font table holds IBM-supplied Simplified Chinese characters as well as user-defined characters. A 32x32 DBCS font table holds 32x32 pel character images of a double-byte character set, including its user-defined characters. The system-recognized identifier for the object type is *IGCTBL.

DBCS-graphic

Pertaining to a character string in which each character is represented by 2 bytes. Used only with the EBCDIC encoding scheme. The character string does not contain shift-out (SO) and shift-in (SI) characters. Contrast with DBCS-either, DBCS-only, and DBCS-open.

DBCS number

The decimal value, 5 digits in length, that identifies a double-byte character.

DBCS-only

Pertaining to a character string that is only bracketed DBCS. Contrast with DBCS-either, DBCS-graphic, and DBCS-open.

DBCS-open

Pertaining to a character string that can be a mixture of SBCS and bracketed DBCS. Contrast with DBCS-either, DBCS-graphic, and DBCS-only.

DBCS sort table

A system-supplied object that contains sequencing information to sort double-byte characters. The system-recognized identifier for the object type is *IGCSRT. See also master sort table and active sort table.

DBMS

See database management system (DBMS).

DB2 UDB for AS/400

See DB2 Universal Database for AS/400.

DB2 UDB Query Manager

A collection of tools used to obtain information from the AS/400 database. DB2 UDB for AS/400 Query Manager can also be used to create query definitions, to run new or existing query definitions, or to format query information.

DB2 UDB Query Manager and SQL Development Kit

The IBM licensed program that is one of the DB2 UDB family of products. Query Manager allows users to develop SQL queries and reports. The SQL Development Kit allows programmers to develop SQL applications.

DB2 Universal Database for AS/400

The integrated relational database manager on AS/400. It provides access to and protection for data. It also provides advanced functions such as referential integrity and parallel database processing.

DCC

See data country code (DCC).

DCE

(1) See Distributed Computing Environment (DCE).

(2) See data circuit-terminating equipment (DCE).

D-channel

In ISDN, a common channel used for signaling and management of the network. Contrast with B-channel.

DCT

See destination control table (DCT).

DDE

See dynamic data exchange (DDE).

DDE client

In VisualAge RPG, a part that provides the function of receiving DDE data from another DDE-enabled application.

DDE server

(1) An OS/2 operating system application and a Microsoft Windows PC application that takes the dynamic data exchange (DDE) requests from the client application and translates the DDE requests into data queue function calls.

(2) In VisualAge RPG, a program entity that provides DDE data to another DDE-enabled application. In VisualAge RPG, all components have DDE server functionality.

DDI

See distributed data interface (DDI).

DDL

See data definition language (DDL).

DDM

See distributed data management (DDM).

DDM file

A system object with type *FILE, created by a user on the local (source) system, that identifies a data file that is kept on a remote (target) system. The DDM file provides the information needed for a local system to locate a remote system and to access the data in the remote data file.

DDN

See Defense Data Network (DDN).

DDS

(1) See data description specifications (DDS).

(2) See Dataphone digital service (DDS).

DDSA

See digital data service adapter (DDSA).

DEA

See Data Encryption Algorithm (DEA).

dead-letter queue

In MQSeries, a queue to which a queue manager or application sends messages that cannot be delivered to their correct destination.

deadlock

A state of inaction that occurs when several processes are waiting for a resource that will not become available because it is being held by another process that is in a similar wait state.

deallocate

To release a resource that is assigned to a specific task. Contrast with allocate.

debug

To detect, diagnose, and eliminate errors in programs.

debugger

A tool used to detect and trace errors in computer programs.

debugging line

(1) A COBOL statement run only when the WITH DEBUGGING MODE clause is specified. Debugging lines can help determine the cause of an error.

(2) In COBOL, any line with a D in the indicator area of the line.

debugging section

In COBOL, a declaratives section that receives control when an identifier, file-name, or procedure-name is encountered in the Procedure Division.

debug mode

(1) A mode in which a program provides detailed output about its activities to aid a user in detecting and correcting errors in the program itself or in the configuration of the program or system.

(2) An environment in which programs can be tested.

decimalization table

In Cryptographic Support, a table of 16 decimal characters that is used to convert a hexadecimal value to a decimal value. Each hexadecimal digit is used as an offset in the (decimalization) table and is replaced with the value found there.

decimal position

(1) The location of the decimal point in a series of numbers.

(2) Numbers to the right of the decimal point. For example, 4.009 has three decimal positions.

declaration

In the C language, a description that makes an external object or function available to a function or a block statement.

declaratives

In COBOL, a set of one or more special-purpose sections, at the beginning of the Procedure Division that can be used for error checking or debugging.

declarative sentence

In COBOL, a compiler-directing statement that specifies when a debugging section or an exception/error procedure is to be run.

decompression

A function that exchanges control characters for actual data. See also compression.

decrypt

(1) In Cryptographic Support, to convert ciphertext into plaintext. Contrast with encrypt.

(2) To decipher data.

decryption

In computer security, the process of transforming encoded text or ciphertext into plaintext.

dedicated save operation

An operation that the user runs to save objects when no other jobs are running. Contrast with save-while-active operation.

Dedicated Server for Domino (DSD)

An AS/400 server that is specially designed to run Lotus Domino servers and applications.

dedicated service tools (DST)

The part of the service function used to service the system when the operating system is not running.

dedicated system

A system intentionally reserved for a single job or task.

de-edit

In COBOL, the logical removal of all editing characters from a numeric edited data item to determine the unedited numeric value of the item.

default

(1) A value, attribute, or option that is automatically supplied or assumed by the system or program when no value is specified by the user.

(2) In DDS, the value specified by the user with the DFT or DFTVAL keyword in DDS.

(3) In DB2 UDB for AS/400, a predetermined value, attribute, or option that is supplied by the system when no value is specified by the user. For example, the default of a column is blanks if the data type is character, or zeros if the data type is numeric.

default configuration

In OSI, the set of default configuration and initialization values supplied with OSI Communications Subsystem. The user can change the default configuration, which is provided by initial records supplied in the subsystem information base shipped with OSI Communications Subsystem.

default delivery

The method of delivering messages to a message queue without interrupting the job, and sending the system-assigned reply for any messages requiring a reply. Messages are placed on the message queue only if the message queue is QSYSOPR; otherwise, the messages are discarded by the system. For messages requiring a reply, replies are sent before the messages are discarded.

default element

In DCE Remote Procedure Call, an optional profile element that contains a nil interface identifier and object UUID, and that specifies a default profile. See default profile, profile, and profile element.

default entry point

An entry point in a user's program that receives control from the operating system when a user runs an application.

default error handler

The part of the RPG logic cycle that handles program or file exceptions/errors when program or file exceptions/errors are not controlled by the programmer.

default focal point

In SNA, a network node that receives alerts from nodes that do not have defined focal points. Contrast with primary focal point.

default form

A temporary object that contains the description of the format of a printed or displayed report, which was built without explicitly specifying a form to be applied against it.

default network message queue

A message queue to which messages related to network activity are sent when either the user profile does not have a message queue specified or the message queue named in the user profile cannot be used.

default network output queue

An output queue to which spooled files are sent when either the user does not have an output queue specified or the output queue name in the user profile cannot be used.

default printer

A printer that is assigned to a system or user and accepts all the printed output from that system or user, if no other printer is specified.

default profile

(1) The profile that is assigned ownership of an object if the original owning profile is deleted or damaged.

(2) In DCE Remote Procedure Call (RPC), a backup profile element that contains a nil interface identifier and object UUID and that specifies a default profile. Each profile can contain only one default element. See default element and profile.

default program

A user-specified program that is assumed when no other program is specifically named on a debug command, or a user-defined program for handling error messages.

default record

A record that consists entirely of default values (numeric fields are filled with zeros; character fields are filled with blanks; and fields of either data type (numeric or character) can be filled with a value specified by the user with the DFT keyword in DDS).

default reply

A system-assigned reply to an inquiry or notify message, which is used when the message queue at which the message arrives is in default delivery mode.

default routing entry

In SNADS, the routing table entry specifying the route to be used when the table contains no explicit routing entry.

default user name

A system-provided name for a user identification for a computer system that does not want to require separate user identifications.

default value

In Backup Recovery and Media Services, a value assumed by a policy or control group when a keyword, command, or control statement with no overriding parameters is processed. A default value is the value assumed for an attribute when no override is specified.

Defense Advanced Research Projects Agency (DARPA)

The United States Department of Defense agency responsible for creating ARPANET, a large TCP/IP network.

Defense Data Network (DDN)

The MILNET, ARPANET, and TCP/IP networks and protocols.

deferred maintenance

The process of waiting until the system can be powered down to repair or replace a failed disk-related hardware component.

deferred work element (DWE)

The catalyst used to call event-driven services controlled within CICS. A DWE causes a unit of work to be scheduled later, normally at the end of the task or just before or after syncpoint.

defined address

A named set of a) Internet Protocol (IP) addresses, or b) interface names and point-to-point profiles. This set is classified as trusted, untrusted, or border.

definite response

In SNA, a value in the response-requested field of the request header (RH). The value directs the receiver of the request to return a response unconditionally, whether positive or negative, to that request. Contrast with exception response.

definition specification

In RPG, a specification used for data definitions. This specification includes defining the following: data structures, data-structure subfields, named constants, arrays, and stand-alone fields.

delay characteristics

The average amount of time required for operations (call setup, call clearing, data transfer, and so forth) to be performed on a packet-switching network.

delayed maintenance

A method of logging changes to an access path for database files and applying the changes the next time the file is opened instead of rebuilding the access path completely or maintaining it immediately. Contrast with rebuild maintenance and immediate maintenance.

delegate

A user who is authorized to work for another user. The authorization can be made by a user or by the office administrator.

delete authority

A data authority that allows the user to remove entries from an object; for example, delete messages from a message queue or delete records from a file. Contrast with add authority. See also execute authority, read authority, and update authority.

delete trigger

A trigger that is associated with a delete operation. See trigger and trigger event.

delimited identifier

In SQL, a sequence of one or more characters of the standard character set enclosed within SQL escape characters that are used to form a name.

delimited scope statement

In COBOL, any statement that includes its explicit scope terminator.

delimiter

(1) A character or sequence of characters that marks the beginning or end of a unit of data.

(2) In COBOL, a character or a sequence of characters that marks the beginning and end of a unit of data, but is not a part of that unit of data.

delimiter token

In SQL, a string constant, a delimited identifier, a symbol (for example, ||, /, *, +, or -), or other special characters. See also token and ordinary token.

demodulate

To return the frequency of a signal to its original level.

denial-of-service attack

In computer security, an assault on a network that brings down one or more hosts on a network such that the host is unable to perform its functions properly. Network service is interrupted for some period.

dependency

In the Application Development Manager feature of the Application Development ToolSet licensed program, the relationship between two parts where one part requires another part in order to be built.

dependent file

The file in a constraint relationship that contains the foreign key. Contrast with parent file. See foreign key.

dependent logical unit

Any logical unit (LU) that is made active by a command from the host system over a data link. Such logical units can be used only as secondary logical units, and can have only one active LU-to-LU session at a time. Contrast with independent logical unit.

dependent logical unit requester (DLUR)

An advanced program-to-program communications (APPC) application that allows dependent secondary logical units (LU 0, 1, 2, and 3) an entry point into the Advanced Peer-to-Peer Networking (APPN) network. DLUR support gives the appearance of having an adjacent connection to VTAM, but allows traversing the APPN network through intermediate nodes.

dependent query

In OfficeVision and Query, a query with a dependent value that is used during record selection to refer to either a file or another query. It is used to coordinate the name; for example, in a form letter, with the list of records that belong to that name.

dependent row

In DB2 UDB for AS/400, a row that has at least one parent row.

dependent table

In DB2 UDB for AS/400, a table that is a dependent in at least one referential constraint. A table can be defined as a dependent in an arbitrary number of referential constraints. A dependent table can also be a parent table.

dependent value

In Query, a reference in a query to another query or to a file. A query with a dependent value is used only in a data field text instruction with column list specified in an OfficeVision document.

dequeue

(1) In OS/400 application programming interfaces, an operation for removing items, such as messages, from a queue.

(2) In Client Access, an operation for removing items, such as messages, from a queue. Contrast with enqueue.

dereferencing

In VisualAge RPG, the action of removing AS/400-specific information from a control.

deregister

In the hierarchical file system, to remove an underlying file system and the specific functions it supports from the application programming interface layer and to make it unavailable to user applications.

derived form

A query management form that was built by converting a Query definition object.

derived name

In REXX, the stem of the symbol, in uppercase, followed by the tail in which all simple symbols have been replaced by their value. It is also the default value of a compound symbol.

derived query

A query management query that was built by converting a Query definition object.

DES

See Data Encryption Standard (DES).

descendent row

In DB2 UDB for AS/400, a row is a descendent of row p if it is a dependent of p or a descendent of a dependent of p.

descendent table

In DB2 UDB for AS/400, a table is a descendent of table T if it is a dependent of T or a descendent of a dependent of T.

descending key

The values by which data is arranged from the highest value to the lowest value of the key field, in accordance with the rules for comparing data items. Contrast with ascending key.

descending key sequence

The arrangement of data in order from the highest value of the key field to the lowest value of the key field. Contrast with ascending key sequence.

descending sequence

The arrangement of data in order from the highest value to the lowest value, according to the rules for comparing data. Contrast with ascending sequence.

descriptor

(1) In the DCE X/Open Directory Service, a defined data structure that is used to represent an OM attribute type and a single value.

(2) In DCE X/Open Object Management, the means by which the client and service exchange an attribute value and the integers that denote its representation, type, and syntax.

deselect

To cancel a previously selected object.

deselection

The process of removing selection from a previously selected object.

designated approving authority (DAA)

The official who has the authority to accept the security safeguards for an information system. The DAA may be responsible for issuing an accreditation statement that records the decision.

design window

In VisualAge RPG, the window in the GUI design tool suite on which parts are placed to create a user interface.

destination address

In communications, the station for which a frame is intended. Contrast with source address.

destination address field (DAF)

In SNA, a field in a format identification 0 or format identification 1 transmission header that contains the network address of the destination. In a format identification 2 header, the field is called destination address field prime (DAF'). Contrast with origin address field (OAF).

destination control table (DCT)

A table describing each of the transient data destinations used in CICS. This table contains an entry for each extrapartition, intrapartition, and indirect destination.

destination node

In the OSI Communications Subsystem licensed program, a node that is the final recipient of data sent by the local node and the origin of data sent to the local node. A destination node may or may not be an adjacent node. Synonymous with end system. See also adjacent destination node and nonadjacent destination node.

destination NSAP address

In OSI, an NSAP address that identifies a destination node. See also NSAP address.

destination service access point (DSAP)

(1) In OSI, a service access point used to receive data.

(2) In SNA and TCP/IP, a logical address that allows a system to route data from a remote device to the appropriate communications support.

destination system

In SNADS, a system that can receive messages, documents or objects.

destructive data change

An event in which data is modified by a change operation in an application or by a trigger, and then the data is modified again by other trigger actions within the same trigger. See trigger and trigger action.

destructor

In the Distributed Computing Environment (DCE), a user-supplied routine that is expected to finalize and then deallocate a per-thread context value.

detach

In a multithreaded environment, to mark a thread so that the system reclaims the thread resources when the thread ends. If the thread is already ended, the resources are freed immediately.

detail calculation

In RPG, specified calculation operations that are performed for every record read.

detail line

In RPG, a detail record in an output file.

detail record

(1) A record that contains the daily activities or transactions of a business. For example, the items on a customer order are typically stored in detail records. Contrast with header record.

(2) In RPG, an output record produced during the detail output operation of the RPG program cycle. Contrast with total record.

detail report

In Query, a report that contains all the information produced by a query. Contrast with summary report.

details view

A standard contents view in which a small icon is combined with text to provide descriptive information about an object. The text is arranged in rows and columns so one row is for each object and one column is for each type of descriptive information displayed.

detail time

That part of the RPG program cycle in which calculation and output operations are performed for each record read. Contrast with total time.

detected access transmission error (DTSE) in

In Performance Tools, the number of times the network termination 1 (NT1) notifies the terminal equipment (TE) of an error in data crossing the U interface of the integrated services digital network (ISDN) from the line transmission termination (LT) to the NT1. The NT1 reports the errors to the TE through the maintenance channel S1.

detected access transmission error (DTSE) out

In Performance Tools, the number of times the network termination 1 (NT1) notifies the terminal equipment (TE) of an error in data crossing the U interface of the integrated services digital network (ISDN) from the NT1 to the line transmission termination (LT). The NT1 reports the errors to the TE through the maintenance channel S1.

determinant

A value resulting from a mathematical operation on an array.

DEVD

See device description.

development folder

In System Manager, a folder containing documents for a load that is being developed.

development group

In the Application Development Manager feature of the Application Development ToolSet licensed program, a group in the project hierarchy where part development is done.

development library

In System Manager, the library containing all or part of a product that is being developed.

device

(1) A piece of equipment that is used with the computer. A device does not generally interact directly with the system, but is controlled by a controller. Each device has a device description associated with it, and often also has a job associated with it. Devices can be workstations, printers, diskette units, tape units, or remote systems.

(2) In Backup Recovery and Media Services, an IBM tape reel or cartridge unit, or any other unit containing removable media, which is available to the AS/400 system for use in Backup Recovery and Media Services processing.

device address

A unique identifier for each device so it is recognized by the system.

device attributes feedback area

In the C language, an area that allows a user to obtain information about a specific device.

device class

The generic name for a group of device types. For example, all display stations belong to the same device class. Contrast with device type.

device configuration

The physical placement of display stations, printers, and so forth; and the configuration descriptions that describe the physical configuration to the system and describe how the configuration will be used by the system. See also line configuration and controller configuration.

device dependence

The reliance on the characteristics of particular types of devices used in writing and running programs or in performing functions. Contrast with device independence.

device-dependent

Pertaining to a function that can be accomplished only if particular types of devices are available. Contrast with device-independent.

device description

An object that contains information describing a particular device or logical unit (LU) that is attached to the system. A device description is a description of the logical connection between two LUs (local and remote locations). The system-recognized identifier for the object type is *DEVD.

device driver

A personal computer program that provides an interface between a hardware device and an application program on a personal computer. Device drivers are loaded into memory when the personal computer is started, and unloaded when the personal computer is turned off.

device emulation

The programming that allows one device to appear to the user or to a system as another device. See also 5250 emulation and 3270 device emulation.

device file

One of several types of the system object type *FILE. A device file contains a description of how data is to be presented to a program from a device or how data is to be presented to the device from the program. Devices can be display stations, printers, diskette units, tape units, or remote systems.

device independence

The capability to write and run programs or perform functions without regard for the physical characteristics of devices. Contrast with device dependence.

device-independent

Pertaining to a function that can be accomplished without regard for the characteristics of particular types of devices. Contrast with device-dependent.

device name

The symbolic name of an individual device.

device object

A device that provides a means of communication between a computer and the outside world. A printer is an example of a device object.

device parity protection

A function that protects data stored on a disk unit subsystem from being lost because of the failure of a single disk unit in the disk unit subsystem. When a disk unit subsystem has device parity protection and one of the disk units in the subsystem fails, the system continues to run. The disk unit subsystem reconstructs the data after the disk unit in the subsystem is repaired or replaced. Contrast with checksum protection and mirrored protection. See also RAID-5.

device selection character

In BSC, the control character that is sent to a receiving system or to a device connected to a receiving system to select that device to receive the output.

device table

A list of finance devices supported by the AS/400 system to be used by a finance job.

device token

In the GDDM function, an 8-byte code, required to set the devices to a predefined set of hardware characteristics.

device type

The generic name for a group of devices. For example, 5219 for IBM 5219 Printers. Contrast with device class.

DFHAID

A COBOL copybook containing the symbolic names for all the AID keys in CICS.

DFS

See Distributed File Service (DFS).

DFU

See data file utility (DFU).

DHCF

See distributed host command facility (DHCF).

DHCP

See Dynamic Host Configuration Protocol (DHCP).

DIA

See Document Interchange Architecture (DIA).

diacritic

An accent near or through a letter or combination of letters indicating a phonetic value different from that given the unmarked or otherwise marked letters.

DIA document distribution services

The set of services that allows office users to send, receive, file, print, change details of, and query electronic mail.

diagnostic

Pertaining to the detection and isolation of an error.

diagnostic message

A message that contains information about errors or possible errors. This message is generally followed by an escape message.

dialed number identification service (DNIS)

In telephony, a number supplied by the public telephone network to identify a logical called party. For example, two 800 numbers might both be translated to a single real telephone number. The DNIS is sent when the real telephone number is called to allow end users to distinguish which service is being called when a call arrives to the real number. Also known as called number or called party.

dialog

In an interactive system, a series of related inquiries and responses similar to a conversation between two people.

dialog box

A movable window containing controls that enable a user to provide information required by an application so that it can continue to process a user request.

dialog management

In OSI, a session-layer service that controls which peer application entity has permission to send.

dialog variable

In the user interface manager (UIM), an element in a panel group that is used to pass data values between two programs or between a program and a user. The values for all dialog variables in a panel group are stored in a variable pool. See also variable pool.

Dial-Up Networking

Microsoft software for Windows 95 and Windows 98 personal computers that allows a modem to dial into the AS/400 system.

DIB

See directory information base (DIB).

DIF

See data interchange format (DIF).

Diffie-Hellman group

A public, key-exchange algorithm that is used for securely establishing a shared secret over an insecure channel. During Phase II negotiations, the Diffie-Hellman group prevents someone who intercepts your key from deducing future keys that are based on the one they have.

digit

Any of the numerals from 0 through 9.

digital

Pertaining to data in the form of digits. Contrast with analog.

digital certificate

A form of personal identification that can be verified electronically. Only the certificate owner who holds the corresponding private key can present a certificate for authentication through a Web browser session. Anyone can verify that the certificate is valid by using a readily available public key.

digital data service adapter (DDSA)

In data communications, a device used when sending and receiving data using a nonswitched digital data service. Compare with modem.

digital envelope

In the context of SET programs, a package of encrypted data and the encryption key.

digital signature

Information that is encrypted with an entity's private key and is appended to a message to assure the recipient of the authenticity and integrity of the message. The digital signature proves that the message was signed by the entity that owns, or has access to, the private key.

digital versatile disc (DVD)

See digital video disc (DVD).

digital video disc (DVD)

An optical disc that has the same overall dimensions of a CD-ROM, but has significantly higher capacities than a CD-ROM. DVDs are also double sided, whereas CD-ROMs are single sided. Also known as digital versatile disc, a DVD holds a minimum of 4.7GB (gigabytes), enough for a full-length movie. The DVD specification supports disks with capacities of from 4.7GB to 17GB and access rates of 600 KBps to 1.3 MBps.

digit position

In COBOL, the amount of physical storage required to store a single digit. This amount can vary depending on the usage specified in the data description entry that defines the data item. If the data description entry specifies that the USAGE IS DISPLAY, then a digit position is synonymous with a character position.

dimension

In System Manager, the interfaces that define guidelines, standards, services, and other interfaces for integrating systems management applications. The three SystemView dimensions are end-use, application, and data. Defined interfaces exist between each of the dimensions.

direct access

A file access method allowing reading and writing of records in an arbitrary order. Contrast with keyed access and sequential access.

directive

(1) In the C language, a statement that begins with the symbol # and is interpreted by the preprocessor during compilation.

(2) A statement that is used in the configuration file for the Internet Connection Server to define a particular setting for the server.

(3) A keyword in the startup file that identifies one aspect of the configuration. Examples of directives are directory, primary, secondary, cache, forwarders, sortlist, $include, options, xfrnets, and bogusns.

direct manipulation

The use of a pointing device to work with objects, rather than through menus. For example, changing the size of a window by dragging one of its edges is direct manipulation.

direct merge

In the OfficeVision program, a type of data/text merge that allows the user to copy data from a completed query report directly into a document. See also column list merge and multiple letters merge.

direct monitor handler

An exception handler that allows the application programmer to directly declare an exception monitor around limited high-level language source statements. For ILE C, this capability is enabled through the #pragma statement.

directory

(1) An object in a file system that is used to locate objects by user-recognized names. A directory contains a list of objects belonging to that directory. The list of objects in a directory may contain other directories.

(2) An AS/400 object of type *DIR that contains the names and controlling information for other objects or other directories.

(3) In the Distributed Computing Environment (DCE), a logical unit for storing entries under one name in one namespace. Also a collection of open systems that cooperate to hold a logical database of information about a set of objects in the real world.

(4) In a hierarchical file system, a grouping of related files and directories, such as a folder containing related documents. A directory may hold zero or more entries, which refer to other directories and files.

(5) In OSI, a repository of information about objects. As defined in the X.500 directory standards, a directory is both a repository of information and the set of services provided to enable its users to access the information in the repository.

(6) In Client Access, a list of the files that are stored on a disk or diskette. A directory also contains information about the file, such as size and date of last change. See also RDB directory.

directory access protocol (DAP)

In OSI, the X.500 protocol that a directory user agent uses to obtain directory information from a remote directory system agent.

directory entry

A entry in the system distribution directory. A directory entry contains information about the user, such as user ID and address, system name, profile name, mailing address, and telephone number.

directory information base (DIB)

In OSI, an X.500 term indicating a collection of all directory information in a directory system made up of one or more cooperating directory system agents.

directory pointer

In the hierarchical file system, the representation of the position of the next directory entry to be read.

directory server

A server that can add, delete, change, or search a directory on behalf of a client.

directory service

(1) In OSI, the service by which an open system can access directory information. Directory service can be provided locally within an open system, or it can be obtained from another open system using the directory service protocols defined by ISO/CCITT. In OSI Communications Subsystem, directory service is used to obtain the presentation address and other attributes of application entities. See also directory system agent and directory user agent.

(2) An OS/400 service that provides access to directory information. See also Directory Services.

Directory Service

A Distributed Computing Environment component that is a central repository for information about resources in a distributed system. See Cell Directory Service (CDS).

Directory Services

A set of OS/400 services that support Lightweight Directory Access Protocol (LDAP). These services consist of client application programming interfaces (for OS/400 Integrated Language Environment and Microsoft Windows applications) and an LDAP-enabled server (directory service). See also directory service.

directory shadowing

The capability of a system to duplicate Enterprise Address Book (EAB) data from one installation of the EAB to another, such that whenever an addition, change, or deletion is made to the EAB on a given system, it is available to all EAB installations within the network.

directory system agent (DSA)

In OSI, an application process residing in an open system that provides directory service to other open systems.

directory user agent (DUA)

In OSI, an application process residing in an open system that serves as the agent that obtains directory services for that open system. The agent can obtain the services either locally or from a remote directory system agent.

direct user

A person enrolled in the system distribution directory who is authorized to sign on and use office functions directly. Contrast with indirect user.

disc

A direct-access storage medium with optically recorded data.

DISC

See disconnect (DISC).

discipline

In System Manager, a grouping of systems management tasks that support an enterprise's information system environment. Examples of disciplines are change management and problem management.

disconnect (DISC)

In communications, the transmission control character that is part of the sequence for disconnecting a switched line.

disconnect (DISC) character

In data communications, the part of the BSC transmission control sequence for ending the connection on a switched line.

disconnected mode (DM)

In communications, a response from a secondary station indicating that it is logically disconnected from the link.

disconnect time-out

An indication that a switched BSC connection was disconnected because there was no activity on the connection for a specified length of time.

discovery

The automatic detection of a network topology change, for example, new and deleted nodes or links.

discriminator

In DCE Remote Procedure Call, the data item that determines which union case is currently used.

disk

A direct-access storage medium with magnetically recorded data.

disk drive

A device for moving and controlling the disk.

disk enclosure

A sealed container that holds the read/write head and disk assembly within a disk unit.

diskette

A thin, flexible magnetic disk permanently stored in a semirigid protective jacket.

diskette drive

The device used to read or write data on a diskette as the diskette rotates within its protective jacket.

diskette file

A device file created by the user for a diskette unit.

diskette unit

A physical enclosure containing one or more diskette drives.

diskette writer

A system program that writes spooled files to a diskette unit. See also printer writer and spooling writer.

diskette 1

A diskette that contains information on only one side.

diskette 2D

A diskette that contains information on both sides, and with twice the amount of information stored in the same space as a diskette 1. Therefore, a diskette 2D holds approximately four times the amount of information as a diskette 1.

disk operating system (DOS)

An operating system for personal computers that can only perform tasks one at a time.

disk pool

An auxiliary storage pool that contains only disk units.

disk unit

A physical enclosure containing one or more disk drives.

displacement

The distance from the beginning of a record, block, or segment to the beginning of a particular field.

display attribute

In computer graphics, a property that is assigned to a display element, to a display segment, or to the complete display image; for example, a bright intensity or particular color.

display file

A device file to support a display station.

display image

In 3270 emulation, the x-character block (where x is the maximum number of characters that can fit on the display screen, or 1920 for printers) that contains data in the sequence in which it would appear on the display screen or the printer. When creating the display, the user can specify the display image with or without field definitions, such as position, length, and other attributes.

display layout sheet

In SDA, a form used to plan the location of data on the display.

display point

In the GDDM function, the smallest addressable area on the screen, sometimes called a picture element (pel), that defines the resolution of the characters or images.

display screen

The part of the display device, which is similar to a television (TV) picture tube, used to display information entered or received at a display station.

display session

A PC program that allows a personal computer to emulate a display station.

display station

A device that includes a keyboard from which an operator can send information to the system and a display screen on which an operator can see the information sent to or the information received from the system.

display station pass-through

A communications function that allows a user to sign on to one system (either an AS/400 system, System/38, or System/36) from another system (either an AS/400 system, System/38, or System/36) and use that system's programs and data. Sometimes called pass-through or 5250 pass-through.

distinguished encoding

In the DCE X/Open Directory Service, the restrictions to the Basic Encoding Rules designed to ensure a unique encoding of each ASN.1 value, defined in the X.500 Directory Standards (CCITT X.509).

distinguished name

(1) In OSI, a multipart hierarchical name that can be used to identify OSI objects globally. Each part of a distinguished name is called a relative distinguished name.

(2) In computer security, the name and address of the person and organization to whom a certificate has been issued. A name that uniquely identifies a Notes user in an address book.

(3) A name that uniquely identifies a Notes user in an address book.

distributed application

In MQSeries message queuing, a set of application programs that can each be connected to a different queue manager, but that collectively comprise a single application.

distributed computing

A type of computing that allows computers with different hardware and software to be combined on a network, function as a single computer, and share the task of processing application programs.

Distributed Computing Environment (DCE)

A comprehensive, integrated set of services that supports the development, use, and maintenance of distributed applications. DCE is independent of the operating system and network; it provides interoperability and portability across heterogeneous platforms.

distributed data

Data that is stored on more than one system and is available to remote users and application programs. See also distributed relational database and distributed file management.

distributed database

Relational or nonrelational data that is spread across more than one database in a network of systems and is accessible as if it were in a local database. In a network of AS/400 systems, a distributed database is always a distributed relational database. See also distributed relational database. Contrast with distributed file management.

distributed data interface (DDI)

An optical fiber-based LAN using the ANSI X3T9.5 standard for a token-passing ring MAC protocol and its physical attachments. Stations, concentrators, and bridges in a DDI network are physically connected to one or both of a pair of counter-rotating rings operating at 100Mbps.

Note:

The term DDI is used to represent all LAN types based on the fiber distributed data interface (FDDI) specifications, regardless of the media used (optical fiber, copper, or shielded twisted pair).

distributed data management (DDM)

A function of the operating system that allows an application program or user on one system to use database files stored on remote systems. The systems must be connected by a communications network, and the remote systems must also be using DDM.

Distributed Data Management (DDM) Architecture

The architecture used by the distributed file management and the distributed relational database protocol to define the protocol used for communicating between two systems using the distributed file management and the distributed relational database.

distributed file management

A function of the operating system that allows an application program or user on one system to use database files stored on remote systems. The systems must be connected by a communications network, and the remote systems must also be using distributed file management. Contrast with distributed database.

Distributed File Service (DFS)

A Distributed Computing Environment (DCE) component that provides a file service that joins the local file systems of several File Server machines, making the files equally available to all DFS client machines.

distributed host command facility (DHCF)

A function of the operating system that supports the data link between a System/370 terminal using an AS/400 application in an HCF (Host Command Facility) environment.

distributed processing

Processing in which resources or functions are dispersed among two or more interconnected processors, typically over a network.

distributed program link (DPL)

A link that enables an application program running on one CICS system to link to another application program running in another CICS system.

Distributed Protocol Interface (DPI)

An extension to Simple Network Management Protocol (SNMP) agents that permits users to dynamically add, delete, or replace management variables in the local Management Information Base (MIB) without requiring recompilation of the SNMP agent.

distributed queue management

In MQSeries message queuing, the setup and control of message channels to queue managers on other systems.

distributed relational database

Relational data that is spread across more than one database in a network of systems and that is accessible as if it were in a local database. See also Distributed Relational Database Architecture (DRDA). Contrast with distributed file management.

Distributed Relational Database Architecture (DRDA)

A connection protocol for distributed relational database processing that IBM's relational database products use. The DRDA protocol comprises protocols for communication between an application and a remote database, and communication between databases. The DRDA protocol provides the connections for remote and distributed processing. The DRDA protocol is built on the Distributed Data Management Architecture.

distributed service

A Distributed Computing Environment (DCE) service that is used mainly by administrators to manage a distributed environment. These services include DTS, Security, and Directory.

distributed systems node executive (DSNX)

A function of the operating system that receives and analyzes requests from the NetView Distribution Manager licensed program on a host system. If the request is directed to the system that receives it, the request is processed on that system or on a personal computer directly attached to that system. If the request is intended for a different system, it is routed toward its destination.

Distributed Time Service (DTS)

A Distributed Computing Environment (DCE) component that provides a way to synchronize the times on different hosts in a distributed system.

distributed transaction processing (DTP)

A process that enables a CICS transaction to communicate with a transaction running in another system.

distributed unit of work (DUW)

In DB2 UDB for AS/400, a method of accessing distributed relational data in which a user or application can, within a single unit of work, read and update data on multiple database management systems (DBMSs). The user or application directs each SQL statement to a particular DBMS for execution at the DBMS. Each SQL statement may access only one DBMS.

distribution

A piece of electronic mail.

distribution catalog

In Managed System Services, a list of objects, identified by SNA global names, with associated object characteristics and indications as to where the objects are located. Objects may be stored as standard AS/400 objects (in a library or folder) or in the distribution repository.

distribution document

An internal document that contains the document content and the document details for a distribution, such as a note or document.

distribution list

A list of system distribution directory entries, which allows users to send messages, notes, and documents to a group of users in one step.

distribution media

(1) The media (diskette, tape, or CD-ROM) on which software is shipped from IBM or another supplier. See installation media.

(2) The media that a central site creates and distributes to target systems. Contrast with installation media.

distribution queue

In SNADS, a list of documents or mail waiting to be sent to users or libraries on remote systems.

distribution recipient index

See distribution recipient queue.

distribution recipient queue

An internal object that contains entries for incoming object distributions; incoming document distributions, such as files, notes, or messages; outgoing document distributions; and error distributions.

distribution repository

In SystemView Managed System Services/400, a staging area for objects that are to be sent or have been received. Objects are loaded into the repository to be sent to managed systems at a later time.

distribution requisite program temporary fix (PTF)

A temporary solution to or a bypass of a problem that is necessary to provide a complete solution to correct a problem. The system allows you to apply the distribution requisite PTF either before the PTF that needs it, with the PTF that needs it, or after the PTF that needs it. Contrast also with corequisite program temporary fix (PTF) and prerequisite program temporary fix (PTF).

distribution service level

In SNADS, the combination of priority, capacity, and protection requirements that must be satisfied to receive or send a distribution. SNADS has service levels of fast, status, data high, and data low. Items with a service level of fast, status, or data high are put on the priority queue. Items with a service level of data low are put on the normal queue.

distribution services

The support provided by the operating system to receive, forward, and send electronic mail in an SNA network.

distribution set

All AS/400 licensed programs that are available from IBM.

distribution tracking object

An internal object that is used to control electronic mail.

division header

In COBOL, the reserved words and punctuation that indicate the beginning of one of the four divisions of a COBOL program.

DLC

Data link control. See high-level data link control (HDLC) and synchronous data link control (SDLC).

DLCI

See data link connection identifier (DLCI).

DLE

See data-link-escape (DLE) character.

DLL

See Dynamic Link Library (DLL).

DLO

See document library object (DLO).

DLUR

See dependent logical unit requester (DLUR).

DM

See disconnected mode (DM).

DNIC

See data network identification code (DNIC).

DNIS

See dialed number identification service (DNIS).

DNS

See Domain Name System (DNS).

DNS domain database file

A configuration file that contains information about the domain, such as resource records, that a server administers.

DNS server cache

Periodically updated information on a name server that contains data about the domain that the name server administers.

document

Any collection of data stored in a document object. A document can contain any type of data. For example, the OfficeVision program can store notes, memos, reports, and other items; the Client Access shared folders function can store any data that could otherwise be stored in a PC file; an AS/400 application can store any data into a document by using CL commands, such as FILDOC and RPLDOC. The system-recognized identifier for the document object type is *DOC. See also document library object.

document authority

The definition of what actions a user can perform on a document.

document class

A user-defined character string, 1 through 16 characters long, that characterizes a document. It can be used to search for a filed document. For example, a document that is a memo could have a document class of MEMO; a document that is a report, REPORT.

document description

The 1- through 44-character description of a document, assigned by the user when creating or filing the document.

document descriptor

In the OfficeVision program, the internal description of the document supplied by the system, which contains the object name, user ID, and security associated with that user; and may also contain the document details, such as subject, author, document description, or other identifying information defined by the user for that document. See also document description and document details.

document details

Data that describes the characteristics of a document. For example, the details can include document type, subject, author, and date created.

document format

The selected arrangement of text for a specific document. See also alternate format.

document ID

In the OfficeVision program, a text instruction that describes the document, such as document name and folder name.

Document Interchange Architecture (DIA)

The rules and structure for the exchange of information between office applications. Document Interchange Architecture includes document library services and document distribution services.

document interchange session

The environment that allows office system users and Client Access users to request document library and distribution services from the host system.

document library

The entire collection of documents and folders on a system.

document library object (DLO)

Any system object that resides in the document library, such as RFT and FFT documents, folders, and PC files.

document library services

The service defined by the Document Interchange Architecture (DIA) to work with objects filed in the DIA document library. On the AS/400 system, it is the support that lets office users work with the contents of the document library.

document list

In the OfficeVision program, a list of filed documents that have common characteristics. The document list identifies those documents that satisfy a search pattern specified at the time the search is used. The document list is a document of type DOCLIST.

document name

The 1- through 12-character name for documents in folders, assigned by the user when creating the document. Contrast with library-assigned document name and document object name.

document number

The number assigned to a printed document when a user files that document. The first two digits of the document number are the year, and the last five are in sequence, with the most recent documents having the highest number. For example, the fifth printed document filed in 1989 would have the number 89-00005.

document object name

The 10-character name of a document assigned by the system when a user files the document. Contrast with library-assigned document name and document name.

document password

In the OfficeVision program, a string of characters that give authority to use or read a private document.

document print queue

In the OfficeVision program, a list of output in the output queue or job queue waiting to be printed by the system.

document type

The Document Interchange Architecture type.

document type definition

The definition of a non-Document Interchange Architecture (DIA) document user type that identifies the document type number, name, and text associated with the document.

document type set

A value that allows a logical grouping of document type definitions. Document type sets include the name and the description. A set can contain one or more document types or it can be empty.

document unit object

An internal object that contains the document content and the document details.

do group

(1) A set of commands in a control language program defined by a DO command and an ENDDO command that is conditionally processed as a group.

(2) In RPG, a group of calculations done one or more times based on the results of comparing factor 1 and factor 2 of certain calculation operations (for example, DOUxx). A DO operation and an END operation are the delimiters for a do group.

DOI

See Domain of Interpretation (DOI).

DO loop

A range of statements run repetitively by a DO statement.

domain

(1) A characteristic of an object that controls which programs can access the object. See Administrative Domain, domain name, system domain object, and user domain object,

(2) A set of servers that make up a logical system. For the Client Access for OS/2 licensed program, a set of servers that allocate shared network resources within a single logical system.

(3) For the Client Access for OS/2 licensed program, a set of servers that allocate shared network resources within a single logical system.

(4) For Client Access using OS/2 database tables, the attribute or all possible correct values associated with a column.

(5) In communications, the network resources under control of a particular system services control point (SSCP).

(6) In TCP/IP, a set of hosts. This term is most commonly associated with the Internet. In the Internet, authority for assigning names and addresses is delegated to individual domains. Domains are organized hierarchically. Each domain has authority for the machines within that domain, but not for machines in other domains. See also domain name.

(7) An organization of Notes servers and workstations that use a common Public Address Book; for example, a company or a group within a company.

domain-defined attributes

In OSI X.400, an attribute of the X.400 originator/recipient name that permits the AS/400 system to keep existing addressing conventions. The AS/400 system uses the domain-defined attributes to carry the user ID and address (the two-part network name used in SNADS).

domain name

(1) In LAN Server, the name representing a set of servers that together comprise a single, logical system.

(2) In the Internet suite of protocols, a name of a host system. A domain name consists of a sequence of subnames that are separated by a delimiter character. For example, if the fully qualified domain name (FQDN) of a host system is as400.rchland.vnet.ibm.com, each of the following is a domain name: as400.rchland.vnet.ibm.com, vnet.ibm.com, ibm.com.

domain name server

In the Internet suite of protocols, a server program that supplies name-to-address conversion by mapping domain names to IP addresses. The use of a domain name server allows users to request services of a computer by using a symbolic name, which is easier to remember than an IP address.

domain name space

All of the names in the Domain Name System (DNS).

Domain Name System (DNS)

In the Internet suite of protocols, the distributed database system used to map domain names to IP addresses.

Domain of Interpretation (DOI)

A group of related protocols that uses the Internet Security Association and Key Management Protocol (ISAKMP) to negotiate Security Associations (SAs). A DOI defines payload formats, exchange types, and conventions for naming security-relevant information such as security policies and cryptographic algorithms and modes.

Domino connector

A function of the HTTP Server for AS/400 licensed program that enables Lotus Notes users to access the Internet and to use all of the HTTP Server functions. Specifically, a Domino connector enables Lotus Notes users to combine Notes with e-business applications.

Domino Directory

A database in a Domino domain that provides a domain-wide directory of Domino servers, users, certifiers, foreign domains, and groups. It also contains documents that manage server-to-server communication and server programs. Also referred to as Public Address Book.

Domino for AS/400

See Lotus Domino for AS/400.

dormant state

In DB2 UDB for AS/400, the state of a connection when the connection is suspended. While in the dormant state, no SQL statements use the connection except for commits and rollbacks. Contrast with current state.

DOS

See disk operating system (DOS).

DOS compatibility box

A DOS command prompt in an OS/2 session that allows a user to run most DOS applications.

DOS session

A session created by the OS/2 operating system that supports the independent running of a DOS program. The DOS program appears to run independently of any other programs in the system.

dot matrix

(1) In computer graphics, a two-dimensional pattern of dots that are used for designing an image on the display.

(2) In word processing, a pattern of dots used to form characters. See also picture element (pixel).

dotted decimal notation

The syntactical representation for a 32-bit integer that consists of four 8-bit numbers written in base 10 and separated by periods (dots). IP addresses are represented in dotted decimal notation.

double-byte character

An entity that requires two character bytes.

double-byte character set (DBCS)

A set of characters in which each character is represented by 2 bytes. Languages such as Japanese, Chinese, and Korean, which contain more symbols than can be represented by 256 code points, require double-byte character sets. Because each character requires 2 bytes, the typing, displaying, and printing of DBCS characters requires hardware and programs that support DBCS. Four double-byte character sets are supported by the system: Japanese, Korean, Simplified Chinese, and Traditional Chinese. Contrast with single-byte character set (SBCS).

double-byte coded font

In AFP support, a font in which the characters are defined by 2 bytes: the first defining a coded font section, the second defining a code point. Synonymous with double-byte font. Contrast with single-byte coded font.

double-click

To perform an operation by moving the pointer to an item on the display, and then quickly pressing the mouse button twice.

double precision

The specification that causes a floating-point value to be stored (internally) in the long format (two computer words). Contrast with single precision.

downline

Pertaining to devices that are below a controller, and controllers that are below a communications line in a communications configuration. Contrast with upline.

download

To send programming instructions and files from a host system to an attached device or to another system. For example, transmitting a type style over a communications line to a 6670 printer.

downstream

(1) In the direction of data flow or toward the destination of transmission.

(2) From the processor toward an attached unit or end user. Contrast with upstream.

DPI

See Distributed Protocol Interface (DPI).

DPL

See distributed program link (DPL).

DR

See definite response.

draft

A printed copy of a document that is not yet completed.

draft spacing

In the OfficeVision program, a print option that doubles the line spacing value for printed documents.

drag

To use a pointing device to move or to copy an object. For example, a user can drag a window border to make it larger by holding a button pointing device while moving the pointing device.

drag and drop

To directly manipulate an object by moving it and placing it somewhere else using a pointing device.

drawdown lock

In the Application Development Manager feature of the Application Development ToolSet licensed program, a group name that shows the group to which a part is checked out.

drawing character

In Client Access, a keyboard character that is placed in the cursor position after the cursor is moved with the cursor movement key.

DRDA

See Distributed Relational Database Architecture (DRDA).

DRDA1

The first stage of Distributed Relational Database Architecture (DRDA). In this stage, an application or user on one system can, within a single unit of work, read update data on a single DBMS.

DRDA2

The second stage of Distributed Relational Database Architecture (DRDA). See distributed unit of work (DUW).

drift

In the DCE Distributed Time Service, the change in a clock's error rate over a specified period of time.

driver

(1) A program (and possibly data files) that contain information needed to run a particular unit, such as a plotter, printer, port, or mouse.

(2) A circuit that increases the signal current for sending data over long cables or to many other circuits.

(3) A circuit that sends small electronic signals to a device.

drop-down list

A single selection field in which only the current choice is visible. Other choices are hidden until the user explicitly acts to display the list box that contains the other choices.

DSA

See directory system agent (DSA).

DSAP

See destination service access point (DSAP).

DSC

3270 Information Display System data-stream compatibility.

DSD

See Dedicated Server for Domino (DSD).

DSNX

See distributed systems node executive (DSNX).

DST

See dedicated service tools (DST).

DST-restricted state

The status of the system before an initial program load (IPL) of the operating system is performed. Only dedicated service tools functions are allowed when the system is in the DST-restricted state.

DSU

See data service unit (DSU) or Data Description Specifications Design Utility (DSU).

DTE

See data terminal equipment (DTE).

DTE address

An address that identifies a specific line attached to a given node on an X.25 network. DTE addresses are assigned by the network supplier.

DTE attributes

In OSI, a set of attributes specified by the local node to regulate connection requests with an adjacent node on an X.25 subnetwork. See also inbound DTE attributes and outbound DTE attributes.

DTP

See distributed transaction processing (DTP).

DTS

See Distributed Time Service (DTS).

DTSE in

See detected access transmission error (DTSE) in.

DTS entity

In the DCE Distributed Time Service, the server or clerk software on a system.

DTSE out

See detected access transmission error (DTSE) out.

DUA

See directory user agent (DUA)

Dual Cluster feature

A feature that provides eight cable connections and allows the attachment of up to eight work stations to a 5251 Model 12 Display Station. See Cluster feature.

dummy device

In the GDDM function, an imaginary output device for which the program does all the normal processing but for which no actual output is received.

dump

(1) In problem analysis and resolution, to write, at a particular instant, all or part of the contents of main or auxiliary storage onto another data medium for the purpose of protecting the data or collecting error information.

(2) To copy data from main or auxiliary storage onto an external medium, such as tape, diskette, or printer.

(3) Data copied in a readable format from main or auxiliary storage to an external medium such as tape, diskette, or printer.

dump media

The diskette or the tape to which the user writes the storage dumps.

duplex

(1) Pertaining to communications in which data can be sent and received at the same time. Contrast with half-duplex.

(2) In AFP support, pertaining to printing on both sides of a sheet of paper. Contrast with simplex.

duplicate key value

The occurrence of the same value in a key field or in a composite key in more than one record in a file.

duration

(1) In LAN Server, the time specified for an alias to exist. An alias can be of either permanent or temporary duration. Temporary duration indicates the alias exists only as long as the network server is active. Permanent duration indicates the alias exists until the administrator deletes it.

(2) In DB2 UDB for AS/400, a number that represents an interval of time. See also labeled duration, date duration, time duration, and timestamp duration.

(3) In Backup Recovery and Media Services, the length of time that the designated media is to reside at a location before moving to the next location or returning to the home location. A duration is specified in the move policy.

DUW (distributed unit of work)

See distributed unit of work (DUW).

DVD

See digital video disc (DVD).

DWE

See deferred work element (DWE).

dynamic

Pertaining to events occurring at run time, or during processing.

dynamic access

In COBOL, an access method in which specific logical records can be obtained from or placed into a mass storage file in a nonsequential manner and obtained from a file in a sequential manner during the scope of the same OPEN statement.

dynamic bind

In DB2 UDB for AS/400, when SQL statements are entered interactively, binding is done automatically (that is, as the SQL statements are entered). See also bind and automatic bind.

dynamic connection

A Virtual Private Network (VPN) connection that automatically refreshes the keys that keep your data secure. A dynamic connection also contains proposals that allow your key server to negotiate which parameters to use with the remote key server. Contrast with manual connection.

dynamic data exchange (DDE)

(1) A function of the OS/2 operating system and of the Microsoft Windows program that allows changes made in one application program to be copied to other application programs.

(2) The exchange of data between programs or between a program and a data-file object. Any change the user makes to information in one program or session is applied to the identical data created by the other program. For example, with the DDE feature enabled, the user can select the copy of a spreadsheet that is embedded in a report. If the user makes changes to the copy of the spreadsheet in the report, the changes are made to the original spreadsheet file.

dynamic endpoint

In DCE Remote Procedure Call (RPC), an endpoint that is generated by the RPC runtime for an RPC server when the server registers its protocol sequences. See endpoint and well-known endpoint.

Dynamic Host Configuration Protocol (DHCP)

In the Internet suite of protocols, a client/server protocol that is used to centrally locate and distribute configuration information.

dynamic IP connection

A Virtual Private Network (VPN) connection between a local endpoint and a host with a dynamically assigned Internet Protocol (IP) address.

Dynamic Link Library (DLL)

In the OS/2 operating system, a library containing data and code objects that can be used by programs or applications during loading or at run time, but are not part of the program's executable (.EXE) file.

dynamic naming

In System Manager, the attribute of an application option that specifies whether the option can be stored in libraries and folders named at the time the installation is performed. This attribute allows an application program to be stored even if a library or folder with the same name as one of the application program's primary libraries or folders is already on the customer's system, but is used by an application program with a different registration identifier.

dynamic print management

The use of the PrintManager program to make changes to a print operation without interrupting system functions.

dynamic processing

A method of reading from or writing to a file in a nonsequential order (see random processing) and reading from a file in a sequential order (see sequential processing) with the same OPEN statement.

dynamic program call

A transfer of control from one program or procedure to another program (*PGM) at run time. A dynamic program call is the only way that an original program model (OPM) program can connect to another OPM program.

dynamic retrieval

A storage management operation where selected data is restored back to disk. The retrieval can be either from tape to disk or from disk to disk.

dynamic route

A path that can be automatically located from a peer (locally attached) gateway.

dynamic select/omit

Selection and omission of logical file records performed during processing, instead of when the access path (if any) is maintained. Dynamic select/omit may also be used when no keyed access path exists.

dynamic SQL

Statements that are prepared and processed within a program while the program is running. The SQL source statements are contained in host-language variables rather than being coded directly into the application program. The SQL statement might change several times while the program is running.

dynamic storage

An area of storage that is explicitly allocated by a program or procedure while it is running. Contrast with automatic storage and static storage.

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