D
Return to Glossary.
-
DAA
- See designated
approving authority.
-
daemon
- A program that runs unattended
to perform continuous or periodic functions, such as network control.
-
DAF
- See destination
address field.
-
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.
-
DARPA
- See Defense Advanced Research Projects Agency.
-
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.
-
database (DB)
- A collection of interrelated
or independent data items that are stored together to serve one or more applications.
-
database administrator (DBA)
- A person
who is responsible for the design, development, operation, security, maintenance,
and use of a database.
-
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.
-
database management system (DBMS)
- See database manager.
-
database manager
- A program that manages
data by providing the services of centralized control, data independence,
and complex physical structures for efficient access, integrity, recovery,
concurrency control, privacy, and security.
-
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 cache unit (DC, DCU)
- A high-speed
buffer storage that contains frequently accessed instructions and data to
reduce access time.
-
data character set
- See character set.
-
data circuit-terminating equipment (DCE)
- The equipment that provides signal conversion and coding between the
data terminal equipment (DTE) and the line. The DCE provides all the functions
required to establish, maintain, and end a connection. A DCE may be either
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.
-
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 communication
- Transfer of data
among functional units by means of data transmission protocols.
-
data compression
- The reduction of
data volume on the media when performing save operations.
-
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 or region, that specifies the X.21 call format
used by a network in its International Data Number to call another station.
See also data network identification code.
-
data decompression
- Reconstruction
of data from a compressed format when performing a restore operation.
-
data definition (DD)
- (1) In IDDU, information
that describes the contents and characteristics of a field, record, or file.
- (2) In the C and C++ languages, 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. IBM®.
-
Data Definition Language (DDL)
- A
language for describing data and its relationships in a database.
-
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 division
- 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)
- A
cryptographic algorithm designed to encrypt and decrypt data using a private
key.
-
data file
- (1) In RJE, a remote job input
stream that can contain host system commands and job control language as well
as data.
- (2) 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. See also command file, source 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 (DFC 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
- A form of asynchronous messaging
in which an application sends a message, but does not require a response.
-
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 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
- The condition that
exists as long as accidental or intentional destruction, alteration, or loss
of data does not occur.
-
data interchange
- The use of data
by systems of different manufacture.
-
data interchange format (DIF)
- In iSeries™ Access, a format that presents data in rows and columns.
-
data item
- (1) 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.
- (2) A unit of information
to be processed.
-
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 line
- (1) In the GDDM function, a
line drawn parallel to a chart axis, through a specified value along the other
axis.
- (2) In Business Graphics Utility, a straight line drawn from
either axis that shows the exact data values on the chart.
-
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 layer (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. See also data flow control layer.
-
data link control protocol (DLC)
- The protocol layer used by nodes on a data link to accomplish an orderly exchange
of information.
-
data link escape character (DLE, DLE character)
- In binary synchronous communication (BSC), a 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 the Open Systems
Interconnection reference model, the layer that provides services to transfer
data between entities in the network layer over a communication link. The
data link layer detects and possibly corrects errors that may occur in the
physical layer.
-
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. See also 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 migration
- The movement of data
when the software is upgraded or the data is transferred to a different hardware
server or model.
-
data mode
- In data communications,
a time during which BSC is sending or receiving characters on the communications
line.
-
data multiplexer
- See multiplexed device.
-
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 also 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 or region code, and the last number is the country
or region network identifier. See also data country
code.
-
data object
- (1) An object that conveys
information, such as text, graphics, audio, or video. See also machine object.
- (2) A program variable that provides operational
and possibly representational characteristics to byte strings in spaces.
-
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) In OSI, the syntactic
structure of symbolic expressions and their storage allocation characteristics.
In OSI Communications Subsystem, data structures are created by the Abstract
Syntax Checker.
- (2) An area of storage that defines the layout of
the fields, called subfields, within the area. A data structure is program
described.
-
data terminal equipment (DTE)
- (1) A device
on a data link that sends and receives data, and provides data communications
control functions according to protocols.
- (2) In OSI, a physical node
on a network.
-
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) In programming languages,
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.
- (2) In SQL, an attribute of columns, literals, host variables, special
registers, and the results of functions and expressions.
- (3) An attribute
used for defining data as either numeric or character.
- (4) In OSI,
a category of data clearly defined using a data declaration method, such as
ASN.1 or Pascal.
-
data value
- In Business Graphics Utility,
a single, numeric data item entered as a value for a horizontal line or vertical
line. See also 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 that designates
a day, month, and year. For example, YYYY-MM-DD.
-
date duration
- A DECIMAL(8,0) value
that represents a number of years, months, and days.
-
datetime value
- A value of the data
type DATE, TIME, or TIMESTAMP.
-
DB
- See database.
-
dB
- See decibel.
-
DB2® Query Manager (Query Manager)
- Part of the DB2 Query Manager and SQL Development Kit licensed program that is a
collection of tools used to obtain information from the DB2 UDB for iSeries database. DB2 Query Manager can also be used to create query definitions,
to run new or existing query definitions, or to format query information.
-
DB2 UDB for iSeries
- See DB2 Universal Database™ for iSeries.
-
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 iSeries (DB2 UDB for iSeries)
- The integrated relational database manager on the server.
It provides access to and protection for data. It also provides advanced functions
such as referential integrity and parallel database processing.
-
DBA
- See database
administrator.
-
DBCS
- See double-byte
character set.
-
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.
-
DBCS data
- In DB2 UDB for iSeries, 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. See also DBCS-graphic, DBCS-open, DBCS-only.
-
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. See also DBCS-either, DBCS-open, DBCS-only.
-
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. See also DBCS-either, DBCS-graphic, DBCS-open, graphic data type.
-
DBCS-open
- Pertaining to a character
string that can be a mixture of SBCS and bracketed DBCS. See also DBCS-either, DBCS-graphic, 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.
-
DBMS
- See database
management system.
-
DC
- See data
cache unit.
-
DCA
- See Document
Content Architecture.
-
DCC
- See data
country code.
-
DCE
- See data
circuit-terminating equipment.
-
D-channel
- See delta channel.
-
DCM
- See Digital
Certificate Manager.
-
DCT
- See destination
control table.
-
DCU
- See data
cache unit.
-
DD
- (1) See data
definition.
- (2) See device driver.
-
DDE client
- In VisualAge® RPG, a
part that provides the function of receiving dynamic data exchange (DDE) data
from another DDE-enabled application.
-
DDE server
- In VisualAge RPG, a
program entity that provides dynamic data exchange (DDE) data to another DDE-enabled
application. In VisualAge RPG, all components have DDE server functionality.
-
DDI
- See distributed
data interface.
-
DDL
- See Data
Definition Language.
-
DDM
- See distributed
data management.
-
DDM Architecture
- See Distributed Data Management Architecture.
-
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.
-
DDS
- (1) See data
description specifications.
- (2) See Dataphone
digital service.
-
DDSA
- See digital
data service adapter.
-
DEA
- See Data
Encryption Algorithm.
-
dead-letter queue
- A queue to which
a queue manager or application sends messages that cannot be delivered to
their correct destination.
-
deadlock
- Unresolved contention for
the use of a resource.
-
deallocate
- To release a resource
that is assigned to a specific task.
-
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, filename, or procedure-name
is encountered in the Procedure Division.
-
debug mode
- (1) An environment in which
programs can be tested.
- (2) 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.
-
decibel (dB)
- A unit of signal strength
or loudness, such as the signal on a data communications channel.
-
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 and C++ languages,
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.
-
decrypt
- (1) To decipher data.
- (2) In Cryptographic Support, to convert ciphertext into plaintext. See
also encrypt.
-
decryption
- In computer security,
the process of transforming encoded text or ciphertext into plaintext.
-
dedicated line
- A connection not requiring
dialing to establish communication.
-
dedicated save operation
- An operation
that the user runs to save objects when no other jobs are running. See also save-while-active operation.
-
Dedicated Server for Domino® (DSD)
- An iSeries server that
is specially designed to run Lotus® Domino servers and applications.
-
dedicated service tools (DST)
- (1) Service
functions that are available only from the console and can run when the operating
system is not available, as well as when the operating system is available.
- (2) 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-editing
- 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
- Pertaining to an attribute,
value, or option that is assumed when none is explicitly specified.
-
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 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.
See also 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 password
- A password that
is the same as the service tools user ID. For example, the IBM-supplied QSECOFR
service tools user ID is shipped with a default password of QSECOFR.
-
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
- The profile that
is assigned ownership of an object if the original owning profile is deleted
or damaged.
-
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.
-
Defense Advanced Research Projects Agency (DARPA)
- The United States Department of Defense agency responsible for
creating ARPANET, a large TCP/IP network. This agency was formerly called
the Advanced Research Projects Agency (ARPA).
-
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 (DR)
- In SNA, a
value in the response-requested field of the request header that directs the
receiver of the request to return a response unconditionally, whether positive
or negative, to that request. See also exception response, no 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.
-
defragmentation
- The process of running
a software utility to rewrite fragmented data to contiguous sectors of a computer
storage medium to improve access and retrieval time. See also fragmentation.
-
delay characteristic
- The average
amount of time required for an operation (such as 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. See also immediate maintenance, rebuild 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. See also add authority.
-
delete trigger
- A trigger that is
associated with a delete operation.
-
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
- A flag that is formed by
a character or a sequence of characters in order to group or separate items
of data by marking the beginning and end of a unit of data. The delimiter
is not a part of the flagged unit of data.
-
delimiter token
- In SQL, a string
constant, a delimited identifier, a symbol (for example, ||, /, *, +, or -),
or other special characters.
-
delta channel (D-channel)
- In ISDN,
a common channel used for signaling and management of the network. In a basic
rate interface, the D-channel operates at 16 kilobits per second. In a primary
rate interface, the D-channel operates at 64 kilobits per second. See also bearer channel.
-
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. See also parent file.
-
dependent logical unit (DLU)
- A logical
unit that requires assistance from a system services control point (SSCP)
to instantiate an LU-to-LU session. See also independent
logical unit, 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 row
- A row that contains
a foreign key that matches the value of a parent key in the parent row. The
foreign key value represents a reference from the dependent row to the parent
row. See also parent row.
-
dependent table
- A table that is a
dependent in at least one referential constraint. See also descendent table, parent table.
-
dequeue
- To remove items from a queue.
See also enqueue.
-
dereferencing
- In VisualAge RPG, the
action of removing iSeries-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.
-
descendent row
- A row that is a dependent
of another row or a descendent of a dependent row.
-
descendent table
- A table that is
in a dependent relationship to a parent table, or to another descendent table.
See also dependent table.
-
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. See also 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. See also 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. See also ascending sequence.
-
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
- The location
to which information is to be sent. See also 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'). See
also origin address field.
-
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. A destination node may or may not
be an adjacent node.
-
destination NSAP address
- In OSI,
an NSAP address that identifies a destination node.
-
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. See also source service access point.
-
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.
-
detach
- (1) 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.
- (2) In cross-site mirroring, to disassociate a mirror copy from the
production copy to use the mirror copy for a separate operation, such as to
save data, to run reports, or to perform data mining. Detaching a mirror copy
suspends geographic mirroring.
-
detached copy
- The mirror copy of
an independent disk pool that is disassociated from the production copy in
a cross-site mirroring (XSM) environment.
-
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) In RPG, an output record
produced during the detail output operation of the RPG program cycle. See
also total record.
- (2) 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. See also header record.
-
detail report
- In Query, a report
that contains all the information produced by a query. See also 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. See also total time.
-
detected access transmission error in (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 out (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
- 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. Devices can be workstations,
printers, disk drives, tape units, or remote systems.
-
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. See also device type.
-
device cluster resource group
- A cluster
resource group that contains a list of switchable devices, such as independent
disk pools which reside on a switchable entity. See also switchable entity.
-
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.
-
device dependence
- The reliance on
the characteristics of particular types of devices used in writing and running
programs or in performing functions. See also device
independence.
-
device-dependent
- Pertaining to a
function that can be accomplished, or a program that can be run, only if particular
types of devices are available. See also device-independent.
-
device description (DEVD)
- 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).
-
device domain
- A collection of cluster
nodes that share device resources, such as independent disk pools. For independent
disk pools, the resources are: virtual addresses, disk pool numbers and disk
unit numbers. An independent disk pool can only be accessed by the nodes in
one device domain.
-
device driver (DD)
- A program that
provides an interface between a specific device and the application program
that uses the device.
-
device emulation
- The programming
that allows one device to appear to the user or to a system as another device.
-
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. See also device dependence.
-
device-independent
- Pertaining to
a function that can be accomplished, or a program that can be executed, without
regard for the characteristics of particular types of devices. See also device-dependent.
-
device name
- The symbolic name of
an individual device.
-
device object
- An object that provides
a means of communication between a computer and another piece of equipment,
such as a printer or disk drive.
-
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 subsystem. When a disk-unit subsystem
has device parity protection and one of the disk units in the subsystem fails,
the subsystem continues to run. The disk-unit subsystem reconstructs the data
after the disk unit is repaired or replaced. See also checksum protection, mirrored protection, Redundant Array of Independent Disks.
-
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 a server 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. See also device class.
-
DFC layer
- See data flow control layer.
-
DFHAID
- A COBOL copybook containing
the symbolic names for all the AID keys in CICS.
-
DFU
- See data
file utility.
-
DHCF
- See distributed
host command facility.
-
DHCP
- See Dynamic
Host Configuration Protocol.
-
DIA
- See Document
Interchange Architecture.
-
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 service
- A service that allows 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.
-
dialog
- A series of related inquiries
and responses between a user and an application, similar to a conversation
between two people.
-
dialog box
- A secondary window that
solicits user input for a specific task or subtask. Common examples are the
Print and Save As dialog boxes. Dialog boxes are modal; that is, they must
be closed before the user can continue working in the window that launched
the dialog box.
-
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.
-
Dial-Up Networking
- Microsoft® software
for Windows® 95 and Windows 98 personal computers that allows
a modem to dial into a server.
-
DIB
- See directory
information base.
-
DIF
- See data
interchange format.
-
Differentiated Services
- A quality-of-service
standard between two networks that allows hosts to manage data by traffic
flow.
-
Differentiated Services domain
- A
contiguous portion of the Internet over which a consistent set of Differentiated
Services policies are administered. A Differentiated Services domain can represent
different trust regions, different network technologies (such as cells or
frames), different hosts, or even different routers.
-
Differentiated Services field
- A six-bit
field in the Internet Protocol (IP) header of a data packet that encodes the
Differentiated Services code point. The field replaces the IPv4 IP header
field, which is called type of service (ToS).
-
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 to analog. See also analog.
-
digital certificate
- An electronic
document used to identify an individual, server, company, or some other entity,
and to associate a public key with the entity. A digital certificate is issued
by a certification authority and is digitally signed by that authority.
-
Digital Certificate Manager (DCM)
- (1) An i5/OS™ component that allows i5/OS to be a local Certificate Authority (CA),
to create digital certificates for use by servers or users.
- (2) An i5/OS option that registers certificates that are created on the server when
it is acting as a certificate authority (CA). DCM can also be used to register
certificates that other certificate authorities issue. DCM allows you to choose
to associate a user's certificate with its user profile. DCM is also used
to associate digital certificates with various applications so that these
applications can use the Secure Sockets Layer (SSL) for secure communications.
-
digital data service adapter (DDSA)
- In data communications, a device used when sending and receiving data using
a nonswitched digital data service.
-
digital envelope
- In the context of
SET programs, a package of encrypted data and the encryption key.
-
digital signature
- Information that
is encrypted with a 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 or shared secret symmetric key.
-
digital versatile disc
- See digital video disc.
-
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.
-
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. Defined interfaces exist
between each of dimension.
-
DIMM
- See dual
inline memory module.
-
direct access
- A file access method
allowing reading and writing of records in an arbitrary order.
-
directive
- (1) 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.
- (2) A statement that is used in the
configuration file for a web server to define a particular setting for the
server.
-
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 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) In a hierarchical file
system, a grouping of related files and directories. A directory may hold
zero or more entries, which refer to other directories and files.
- (2) A type of file that contains the names and controlling information for other
objects or other directories.
- (3) 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 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.
-
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 directory information on behalf of a client.
See also Directory Server.
-
Directory Server
- A set of i5/OS services that
support Lightweight Directory Access Protocol (LDAP). These services consist
of client application programming interfaces (for i5/OS Integrated Language Environment® and Microsoft Windows applications) and an LDAP-enabled
server (directory server). See also directory server.
-
directory service
- 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.
-
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.
-
DISC
- See disconnect.
-
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 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 timeout
- 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.
-
disk
- A storage device that includes
one or more flat, circular plates with magnetic or optical surfaces on which
information is stored.
-
disk drive
- The mechanism used to
read and write information on a disk.
-
disk enclosure
- (1) The part of a disk
unit that contains the read and write heads, the magnetic disks, and the actuators.
- (2) A sealed container that holds the read/write head and disk assembly
within a disk unit.
-
diskette
- A thin, flexible magnetic
plate that is permanently sealed in a protective cover. It can be used to
store information copies from the disk or another diskette.
-
diskette file
- A device file created
by the user for a diskette unit.
-
diskette unit
- A physical enclosure
containing one or more diskette drives.
-
disk operating system (DOS)
- An operating
system for computer systems that use disks and diskettes for auxiliary storage
of programs and data.
-
disk pool
- An auxiliary storage pool
that contains only disk units.
-
disk pool group
- Made up of a primary
disk pool and zero or more secondary disk pools, each of which are independent
in regard to data storage, but combine to act as one entity.
-
disk unit
- A sealed container that
holds the read and write heads, the magnetic disks, and the actuators. See
also random access memory.
-
disk unit enclosure
- A physical enclosure
containing one or more disk units.
-
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
- See screen.
-
display session
- A PC program that
allows a personal computer to emulate a display station.
-
display station
- A device, usually
equipped with a keyboard and a display device, capable of sending and receiving
information over a communications line.
-
display station pass-through
- A communications
function that allows a user to sign on to one system (either an iSeries server, System/38™, or System/36™) from another system (either an iSeries server, System/38, or System/36) and use that system's programs and data.
-
distinguished name
- (1) A set of name-value
pairs (such as CN=person's name and C=country or region) that uniquely identify
an entity in a digital certificate.
- (2) In OSI, a multipart hierarchical
name that can be used to identify OSI objects globally. The distinguished
name of an object is formed from the sequence of its relative distinguished
names (RDNs) and the name of its superior object.
-
distributed application
- In 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
- See network 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 data
- Data that is stored
on more than one system and is available to remote users and application programs.
-
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 iSeries servers, a distributed database is always a distributed relational
database. See also 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. 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 Architecture (DDM
Architecture)
- A connection protocol that enables communication
between a system that uses distributed file management and a system that uses
distributed relational database architecture.
-
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. See also distributed
database.
-
distributed host command facility (DHCF)
- A function of the operating system that supports the data link between
a System/370™ terminal using an iSeries 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
function of CICS intersystem communication that enables an application program to
ship LINK requests to another application program on a different instance
of CICS.
-
Distributed Protocol Interface (DPI®)
- An extension to the Simple Network Management Protocol (SNMP) agent 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. The distributed protocol interface is defined in Request for Comments
(RFC) 1592.
-
distributed queue management
- In message
queuing, the setup and control of message channels to queue managers on other
systems.
-
distributed relational database
- A database whose tables are stored on different but interconnected computing
systems.
-
Distributed Relational
Database Architecture™ (DRDA®)
- The architecture that defines
formats and protocols for providing transparent access to remote data. Distributed Relational Database Architecture defines
two types of functions, the application requester function and the application
server function.
-
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 transaction processing (DTP)
- A process that enables a CICS transaction to communicate synchronously
with a transaction running in another instance of CICS.
-
distributed unit of work (DUW)
- In DB2 UDB
for iSeries, 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 catalog
- A list of objects,
with references to their locations and associated object characteristics.
-
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 medium on
which the operating system software, a licensed program, or an application
program is distributed to the user. The distribution medium can be any of
several different media supported by the hardware, such as streaming cartridge
tape, 9-track tape, or 3.5-inch diskette.
- (2) The media that a central
site creates and distributes to target systems. See also 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 Managed
System Services, 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 fix
- 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 fix either before the PTF that needs it, with the PTF that needs
it, or after the PTF that needs it. See also corequisite
fix, prerequisite fix.
-
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 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
- See data
link control protocol.
-
DLCI
- See data
link connection identifier.
-
DLC layer
- See data link control layer.
-
DLE
- See data
link escape character.
-
DLE character
- See data link escape character.
-
DLL
- See dynamic
link library.
-
DLO
- See document
library object.
-
DLU
- See dependent
logical unit.
-
DLUR
- See dependent
logical unit requester.
-
DM
- See disconnected
mode.
-
DNIC
- See data
network identification code.
-
DNIS
- See dialed
number identification service.
-
DNS
- See Domain
Name System.
-
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 iSeries Access shared folders function can store any data that could
otherwise be stored in a PC file; a server 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 Content Architecture (DCA)
- An architecture that guarantees information integrity for a document being
interchanged in an office system network. DCA provides the rule for specifying
form and meaning of a document. It defines revisable form text (changeable)
and final form text (unchangeable).
-
document description
- The 1- through
44-character description of a document, assigned by the user when creating
or filing the document.
-
document detail
- Data that describes
a characteristic of a document. For example, a detail can be document type,
subject, author, or date created.
-
document format
- The selected arrangement
of text for a specific document.
-
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 iSeries 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. See also document.
-
document library services
- The services
defined by the Document Interchange Architecture (DIA) to work with objects
filed in the DIA document library. On the system, it is the support that lets
users work with the contents of the document library.
-
document name
- The 1- through 12-character
name for documents in folders, assigned by the user when creating the document.
See also 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.
See also document name.
-
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) 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.
- (2) 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.
-
DOI
- See Domain
of Interpretation.
-
DO loop
- A range of statements run
repetitively by a DO statement.
-
domain
- (1) In TCP/IP, a named set of
hosts. Each domain has authority for the machines within that domain, but
not for machines in other domains.
- (2) In a database, all the possible
values of an attribute or a data element.
- (3) An organization of Notes
servers and workstations that use a common Public Address Book; for example,
a company or a group within a company.
- (4) A logical grouping of resources
in a network for the purpose of common management and administration.
- (5) In communications, the network resources under control of a particular
system services control point (SSCP).
- (6) A set of servers that allocate
shared network resources within a single logical system.
- (7) A characteristic
of an object that controls which programs can access the object. See also domain name, system domain object, user domain object.
-
domain-defined attribute
- In OSI X.400,
an attribute of the X.400 originator/recipient name that permits the iSeries system to
keep existing addressing conventions. The iSeries 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.
See also domain.
- (2) In Internet communications,
a name of a host system. A domain name consists of a sequence of subnames
that are separated by a delimiter character, for example, www.ibm.com.
-
domain name server
- In Internet communications,
a server program that supplies name-to-address conversion by mapping domain
names to IP addresses.
-
domain name space
- All of the names
in the Domain Name System (DNS).
-
Domain Name System (DNS)
- The distributed
database system used to map domain names to IP addresses. See also domain name.
-
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 iSeries 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 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.
-
Domino for iSeries
- See Lotus Domino for iSeries.
-
dormant state
- In DB2 UDB for iSeries, 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. See also current state.
-
DOS
- See disk
operating system.
-
dot matrix
- (1) In word processing, a
pattern of dots used to form characters.
- (2) In computer graphics,
a two-dimensional pattern of dots that are used for designing an image on
the display.
-
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. See also octet.
-
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 two bytes. These
character sets are commonly used by national languages, such as Japanese and
Chinese, that have more symbols than can be represented by a single byte.
See also single-byte character set, multibyte character set.
-
double-byte coded font (double-byte font)
- A font in which the characters are defined by 2 bytes. The first byte
defines the coded font section; the second byte defines the code point in
the code page specified for that section.
-
double-byte font
- See double-byte coded font.
-
double-click
- To press and release
a mouse button twice in rapid succession in order to perform an operation.
-
double precision
- The specification
that causes a floating-point value to be stored (internally) in the long format
(two computer words). See also single precision.
-
downline
- Pertaining to devices that
are below a controller, and controllers that are below a communications line
in a communications configuration. See also upline.
-
download
- To transfer data from a
computer to a connected device, such as a workstation or microcomputer. Typically,
users download from a larger computer to a diskette or fixed disk on a smaller
computer or from a system unit to an adapter.
-
downstream
- Pertaining to the direction
of data flow, which is toward the destination of a transmission. See also upstream.
-
DPI
- See Distributed Protocol Interface.
-
DPL
- See distributed
program link.
-
DR
- See definite
response.
-
drag
- To use a pointing device to
move 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.
-
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 iSeries 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.
-
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).
-
driver
- (1) A circuit that increases the
signal current for sending data over long cables or to many other circuits.
- (2) A program (and possibly data files) that contain information
needed to run a particular unit, such as a plotter, printer, port, or mouse.
- (3) A circuit that sends small electronic signals to a device.
-
dropping
- In QoS, the simplest form
of traffic conditioning where noncompliant packets are discarded.
-
DSA
- See directory
system agent.
-
DSAP
- See destination
service access point.
-
DSD
- See Dedicated
Server for Domino.
-
DSNX
- See distributed
systems node executive.
-
DST
- See dedicated
service tools.
-
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
- (1) See Data
Description Specifications Design Utility.
- (2) See data service unit.
-
DTE
- See data
terminal equipment.
-
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 attribute
- In OSI, an attribute
specified by the local node to regulate connection requests with an adjacent
node on an X.25 subnetwork.
-
DTP
- See distributed
transaction processing.
-
DTSE in
- See detected access transmission error in.
-
DTS entity
- In the DCE Distributed
Time Service, the server or clerk software on a system.
-
DTSE out
- See detected access transmission error out.
-
DUA
- See directory
user agent.
-
dual-homed host
- See multihomed host.
-
dual inline memory module (DIMM)
- A small circuit board with memory-integrated circuits containing signal and
power pins on both sides of the board. See also single
inline memory module.
-
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) Data that is copied in a readable
format from main or auxiliary storage to an external medium such as tape,
diskette, or printer.
- (2) To record or copy, at a particular instant,
data from one storage device onto another storage device in order to protect
the data and debug the program.
-
dump media
- The diskette or the tape
to which the user writes the storage dumps.
-
duplex
- (1) Pertaining to printing on
both sides of a sheet of paper.
- (2) Pertaining to communications in
which data can be sent and received at the same time. See also half-duplex.
-
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 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.
- (3) In SQL, a number that represents
an interval of time.
-
DUW
- See distributed
unit of work.
-
DVD
- See digital
video disc.
-
DWE
- See deferred
work element.
-
dynamic
- Pertaining to events that
occur 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
- A process by which SQL
statements are bound as they are entered. See also static 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.
See also manual connection.
-
dynamic data exchange
- 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 Host Configuration Protocol (DHCP)
- A communications protocol that is used to centrally manage configuration
information. For example, DHCP automatically assigns IP addresses to computers
in a network. The Dynamic Host Configuration Protocol is defined by the Internet
Engineering Task Force (IETF).
-
dynamic IP
- A method of Internet Protocol
(IP) address management in which Dynamic Host Configuration Protocol (DHCP)
assigns IP addresses to hosts and updates the host IP records in the Domain
Name System (DNS). This method keeps DNS records current as IP address assignments
change.
-
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)
- A file
containing executable code and data bound to a program at load time or run
time, rather than during linking. The code and data in a dynamic link library
can be shared by several applications simultaneously.
-
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. See also static program call.
-
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
- SQL statements that are
prepared and executed at run time. In dynamic SQL, the SQL statement is contained
as a character string in a host variable and is not precompiled. See also static SQL.
-
dynamic storage
- An area of storage
that is explicitly allocated by a program or procedure while it is running.
See also automatic storage, static storage.
-
dynamic string
- See string.