This glossary contains definitions of those terms and abbreviations that
relate specifically to the contents of this book. It also contains terms and
definitions from the IBM® Dictionary of Computing, published
by McGraw-Hill.
If you do not find the term you are looking for, refer to the Index or to the IBM Dictionary of Computing.
- ACB
- Access method control block (VTAM®).
- ACF/NCP/VS
- Advanced Communication Facilities/Network
Control Program/Virtual Storage.
- ACF/VTAM
- Advanced Communication Facilities,
Virtual Telecommunications Access Method. A set of programs that control
communication between terminals and application programs running under VSE,
OS/VS1, and MVS™.
- Advanced Program-to-Program Communication (APPC)
- The general term chosen for the LUTYPE6.2 protocol under Systems Network Architecture
(SNA).
- alternate facility
- An IRC or SNA session that is
obtained by a transaction by means of an ALLOCATE command. Contrast with
principal facility.
- APPC
- Advanced Program-to-Program Communication.
- ATI
- Automatic transaction initiation.
- attach header
- In SNA, a function management header
that causes a remote process or transaction to be attached.
- back-end transaction
- In synchronous transaction-to-transaction
communication, a transaction that is started by a front-end transaction.
- backout
- See dynamic transaction backout.
- bind
- In SNA products, a request to activate a session
between two logical units.
- CDB
- Conversation data block.
- central processing complex (CPC)
- A single physical
processing system, such as the whole of an ES/9000 9021 Model 820, or one physical partition
of such a machine. A physical processing system consists of main storage,
and one or more central processing units (CPUs), time-of-day (TOD) clocks,
and channels, which are in a single configuration. A CPC also includes channel
subsystems, service processors, and expanded storage, where installed.
- CICSplex
- (1) A CICS® complex. A CICSplex consists of two or
more regions that are linked using CICS intercommunication facilities. The
links can be either intersystem communication (ISC) or multiregion operation
(MRO) links, but within a CICSplex are more usually MRO. Typically, a CICSplex
has at least one terminal-owning region (TOR), more than one application-owning
region (AOR), and may have one or more regions that own the resources that
are accessed by the AORs. (2) The largest set of CICS regions or systems to
be manipulated by a single CICSplex SM entity.
- CICSPlex® System Manager (CICSPlex SM)
- An IBM
CICS system-management product that provides a single-system image and a single
point of control for one or more CICSplexes.
- class of service (COS)
- An ACF/VTAM facility that
allows APPC sessions to have different characteristics to provide a user with
alternate routing, mixed traffic, and trunking. Based on their class of service,
sessions can take different virtual routes, use different physical links,
and be of high or low priority to suit the traffic carried on them.
- Common Programming Interface (CPI)
- An SAA standard specifying
the languages, commands, and calls that can be used in an SAA application
program.
- conversation
- A sequence of exchanges between two
transactions over a session, delimited by SNA brackets.
- conversation data block
- An area used by a program
to obtain information about the outcome of a DTP command on an APPC basic
conversation.
- COS
- Class of service.
- CPC
- Central processing complex.
- CPI
- Common Programming Interface.
- conversation
- A sequence of exchanges between transactions
over a session, delimited by SNA brackets.
- cross-system coupling facility (XCF)
- The MVS/ESA cross-system
coupling facility provides the services that are needed to join multiple MVS
images into a sysplex. XCF services allow authorized programs in a multisystem
environment to communicate (send and receive data) with programs in the same,
or another, MVS image. Multisystem applications can use the services of XCF,
including MVS components and application subsystems (such as CICS), to communicate
across a sysplex. See the MVS/ESA Planning: Sysplex Management manual,
GC28-1620, for more information about the use of XCF in a sysplex.
- data link protocol
- A set of rules for data communication
over a data link in terms of a transmission code, a transmission mode, and
control and recovery procedures.
- data security
- Prevention of access to or use of
stored information without authorization.
- distributed transaction processing (DTP)
- The distribution
of processing between transactions that communicate synchronously with one
another over intersystem or interregion links.
- DL/I
- Data Language/I. An IBM database management
facility.
- DTP
- Distributed transaction processing.
- dynamic transaction backout
- The process of canceling
changes made to stored data by a transaction following the failure of that
transaction for whatever reason.
- EIB
- EXEC interface block.
- FMH
- Function management header.
- front-end transaction
- In synchronous transaction-to-transaction
communication, the transaction that acquires the session to another system
and initiates a transaction on that system. Contrast with back-end transaction.
- function management header (FMH)
- In SNA, one or
more headers optionally present in the leading request unit (RU) of an RU
chain. It allows one session partner in a LU-LU session to send function
management information to the other.
- function shipping
- The process, transparent to the
application program, by which CICS accesses resources when those resources
are actually held on another CICS system.
- GDS
- Generalized data stream.
- generalized data stream (GDS)
- The data stream used
for conversations on APPC sessions.
- host computer
- The primary or controlling computer
in a data communication system.
- IMS/VS
- Information Management System/Virtual Storage.
- inquiry
- A request for information from storage.
- intercommunication facilities
- A generic term covering
intersystem communication (ISC) and multiregion operation (MRO).
- interregion communication (IRC)
- The method by which
CICS implements multiregion operation (MRO).
- intersystem communication (ISC)
- Communication between
separate systems by means of SNA networking facilities or by means of the
application-to-application facilities of VTAM.
- IRC
- Interregion communication.
- ISC
- Intersystem communication.
- local resource
- In CICS intercommunication, a resource
that is owned by the local system.
- local system
- In CICS intercommunication, the CICS
system from whose point of view intercommunication is being discussed.
- logical unit (LU)
- A port through which a user gains
access to the services of a network.
- LU
- Logical unit.
- LU-LU session
- A session between two logical units
in an SNA network.
- modegroup
- A VTAM LOGMODE entry which can specify
(among other things) the class of service required for a group of APPC sessions.
- modename
- The name of a modeset.
- modeset
- A group of APPC sessions specified in CICS.
- MRO
- Multiregion operation.
- multiregion operation (MRO)
- Communication between
CICS systems without the use of SNA networking facilities. The systems must
be in the same operating system; or, if the XCF access method is used, in
the same MVS sysplex.
- multitasking
- Concurrent execution of application
programs within a CICS partition or region.
- multithreading
- Use, by several transactions, of
a single copy of an application program.
- MVS
- Multiple Virtual Storage. An alternative name
for OS/VS2 Release 3, or MVS/ESA.
- MVS image
- A single occurrence of the MVS/ESA operating
system that has the ability to process a workload. One MVS image can occupy
the whole of a CPC, or one physical partition of a CPC, or one logical partition
of a CPC that is operating in PR/SM™ mode.
- MVS sysplex
- See sysplex.
- network
- A configuration connecting two or more
terminal installations.
- network configuration
- In SNA, the group of links,
nodes, machine features, devices, and programs that make up a data processing
system, a network, or a communication system.
- Operating System/Virtual Storage (OS/VS)
- A compatible
extension of the IBM System/360 Operating System that supports relocation
hardware and the extended control facilities of System/360.
- OS/VS
- Operating System/Virtual Storage.
- PIP
- Program initialization parameters.
- principal facility
- The terminal or logical unit
that is connected to a transaction at its initiation. Contrast with alternate
facility.
- program initialization parameters (PIP)
- Specially
formatted data passed to a back-end transaction with the CONNECT PROCESS command.
- queue
- A line or list formed by items in a system
waiting for service; for example, tasks to be performed or messages to be
transmitted in a message-switching system.
- RACF®
- The Resource Access Control Facility program
product. An external security management facility.
- region
- A section of the dynamic area that is allocated
to a job step or system task. In this manual, the term is used to cover partitions
and address spaces in addition to regions.
- remote resource
- In CICS intercommunication, a resource
that is owned by a remote system.
- remote system
- In CICS intercommunication, a system
that the local CICS system accesses via intersystem communication or multiregion
operation.
- resource
- Any facility of the computing system or
operating system required by a job or task, and including main storage, input/output
devices, the processing unit, data sets, and control or processing programs.
- rollback
- A programmed return to a prior checkpoint.
In CICS, the cancelation by an application program of the changes it has
made to all recoverable resources during the current unit of work.
- RU
- Request/response unit. In SNA, the basic unit
of information entering or leaving the transmission subsystem. It may contain
data, acknowledgements, control commands, or responses to commands.
- SAA
- Systems Application Architecture®.
- security
- Prevention of access to or use of data
or programs without authorization.
- session
- In CICS intersystem communication, an SNA
LU-LU session.
- SNA
- Systems Network Architecture.
- subsystem
- A secondary or subordinate system.
- synchronization level
- The level of synchronization
(0, 1, or 2) established for an APPC session.
- syncpoint
- Synchronization point. During transaction
processing, a reference point to which protected resources can be restored
if a failure occurs.
- sync level
- synchronization level.
- sysplex
- A systems complex, consisting of multiple
MVS images coupled together by hardware elements and software services. When
multiple MVS images are coupled using XCF, which provides the services to
form a sysplex, they can be viewed as a single entity.
- system
- In CICS, an assembly of hardware and software
capable of providing the facilities of CICS for a particular installation.
- Systems Application Architecture (SAA)
- A set of
common standards and procedures for working with IBM systems and data.
- Systems Network Architecture (SNA)
- The description
of the logical structure, formats, protocols, and operational sequences for
transmitting information units through, and controlling the configuration
and operation of, networks. The structure of SNA allows the end users to
be independent of, and unaffected by, the specific facilities used for information
exchange.
- task
- (1) A unit of work for the processor; therefore
the basic multiprogramming unit under the control program. (CICS runs as
a task under VSE, OS/VS, MVS, or MVS/ESA.) (2) Under CICS, the execution of
a transaction for a particular user. Contrast with transaction.
- TCT
- Terminal control table.
- temporary storage control
- The CICS element that
provides temporary data storage facilities.
- temporary storage table
- A table describing temporary
storage queues and queue prefixes for which CICS is to provide recovery.
- terminal
- In CICS, a device equipped with a keyboard
and some kind of display, capable of sending and receiving information over
a communication channel.
- terminal control
- The CICS element that controls
all CICS terminal activity.
- terminal control table (TCT)
- A table describing
a configuration of terminals, logical units, or other CICS systems in a CICS
network with which the CICS system can communicate.
- terminal operator
- The user of a terminal.
- transaction
- A transaction can be regarded as a
unit of processing (consisting of one or more application programs) initiated
by a single request, often from a terminal. A transaction may require the
initiation of one or more tasks for its execution. Contrast with task.
- transaction backout
- The cancelation, as a result
of a transaction failure, of all updates performed by a task.
- transaction identifier
- Synonym for transaction
name. For example, a group of up to four characters entered by an operator
when selecting a transaction.
- transaction restart
- The restart of a task after
a transaction backout.
- transaction routing
- A CICS facility that allows
terminals or logical units connected to one CICS region to initiate and to
communicate with transactions in another CICS region within the same processor
system or in another CICS system connected by an APPC link.
- transient data control
- The CICS element that controls
sequential data files and intrapartition data.
- unit of work (UOW)
- A sequence of actions that can be
regarded as logically-related for the purposes of CICS error recovery mechanisms.
- UOW
- Unit of work.
- VTAM
- See ACF/VTAM.
- XCF
- Cross-system coupling facility.
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