gtpd3m0dLibrary Guide with Master Index and Glossary

A

AAA
Agent assembly area.

absolute address
In IBM ESA modes, an address that exists after translation and prefixing but before configuration occurs. See also logical address, physical address, real address, and virtual address.

absolute path name
The name of a directory or file expressed as a sequence of directories followed by a file name, beginning from the root directory. Absolute path names begin with a slash (/). (POSIX.1) See also relative path name, path name.

absolute time
The total elapsed time since 00:00 a.m. January 1, 1900 coordinated time (UTC). UTC differs from Absolute Time by the accumulated number of leap seconds since 00:00 a.m. January 1, 1900 UTC.

abstract class
A class that has no objects belonging to it that do not also belong to an additional subclass.

accept
The process by which the base or allocated versions of programs get permanently replaced (updated) with the newly loaded E-type loader versions of these programs.

accept function
The E-type loader function that replaces the programs at the allocated addresses with the programs contained in a specified loadset.

accepted status
The condition where a central processor complex's (CPC) time-of-day clock is synchronous with a synchronization source that is not compatible with the master synchronization source in the complex.

access
To obtain the use of a computer resource. (T) The way in which files are referred to by the computer. The ability to obtain the use of a protected resource. (OSF) To obtain data from or to put data in storage. In computer security, a specific type of interaction between a subject and an object that results in the flow of information from one to the other.

access list
A list that directs the TPF Internet mail server to selectively accept or reject mail from or to specific hosts, domains, networks, host addresses, or mail addresses.

access control
In computer security, ensuring that the resources of a computer system can be accessed only by authorized users in authorized ways.

access control list (ACL)
In TPF Internet mail server support, a list that specifies the users and their access rights for mailboxes.

access mode
A form of access permitted to a file. (POSIX.1)

access permissions
A group of designations that determine whether and how a user can access a file. Types of access permission are read, write, and search.

ACF
Advanced Communications Function.

ACF/VTAM
Advanced Communications Function for Virtual Telecommunications Access Method.

acknowledge message label (AML)
A type of link control block (LCB) that is sent across an SLC link to indicate that all blocks of a multiblock message have been correctly received and acknowledged.

ACL
Access control list.

ACP
Airlines Control Program.

action code
One or more characters at the beginning of a message that identify the type of message to follow.

activate function
The E-type loader function that makes the programs in specified loadsets available for use by new ECBs.

activation level
See activation number.

activation number
A number assigned to every ECB in the system. When entering a program, the activation number determines which version of the program is to be entered. An activation number is also assigned to all programs in a loadset. This allows a user to determine which version of a program is entered.

active entry
The ECB currently in control of the CPU or I-stream engine.

active queue
A mail queue of mail items that have been accepted for delivery, but for which delivery has not yet been attempted.

active user
A user that has been identified to MPIF.

adaptive rate-based (ARB) pacing
A flow control protocol that regulates the flow of data over a high-performance routing (HPR) rapid transport protocol (RTP) connection by adjusting the send rate based on feedback from the receiver. This protocol allows for high link utilization and prevents congestion before it occurs.

address space
A collection of storage that is allocated, and in many ways managed, as a single entity by the TPF system. Each byte in an address space is identified by a unique address. An address space represents an extent of storage available to a program.

adjacent link station (ALS)
The hardware and software that establish a connection between the TPF system and a channel-attached network controller. The adjacent link station is a type 2.1 low-entry node that uses an exchange identification format 3 (XID3) exchange to establish a connection, and sends FID2 PIUs across the connection.

adjunct area
An area in a list entry that is used to hold as many as 64 bytes of data with coupling facility (CF) support. You can use this area to maintain control information about the contents of a data entry. See also data entry and list entry.

Advanced Communications Function (ACF)
A function that allows the TPF system to communicate with other systems, including other TPF systems with the ACF function, using either the SNA Multisystem Networking Facility (MSNF) or the Network Extension Facility (NEF) licensed program.

Advanced Communications Function for Virtual Telecommunications Access Method (ACF/VTAM). An IBM licensed program that controls communications and flow of data in an SNA network. It provides single-domain, multiple-domain, and interconnected network capabilities.

Advanced Program-to-Program Communications (APPC)
See TPF Advanced Program-to-Program Communications (TPF/APPC).

Advanced Program-to-Program Communications (APPC) macro
An assembler macro in an application or program that uses the APPC communications protocol.

AET
Asynchronous event table.

agent
A terminal or workstation user in an airline system; can also indicate any terminal or workstation user.

agent assembly area (AAA)
The terminal control block used to pass information among related messages of a transaction. The AAA was created before SNA support as a terminal control block in an airlines line control (ALC) network.

aggregate
(1) In programming languages, a structured collection of data objects that form a data type. (2) An array, a structure, or a union.

Airlines Control Program (ACP)
The name for earlier versions of the Transaction Processing Facility (TPF).

airlines line control (ALC)
The synchronous line protocol used to control transmission from or to a cluster of terminals attached to terminal interchange units. ALC is also known as SABRE line control.

ALC
Airlines line control.

alias queue object
An MQSeries object, the name of which is an alias for a base queue defined to the local queue manager. When an application or a queue manager uses an alias queue, the alias name is resolved and the requested operation is performed on the associated base queue.

alive timer
A timer used by the TPF system to detect failures for idle rapid transport protocol (RTP) connections in a high-performance routing (HPR) network.

allocator
The program deck that is used as input to the SALO program which, in turn, creates a system allocator table (SAL) and a program allocation table (IPAT). These tables define where each real-time program will reside on DASD.

ALS
Adjacent link station.

ALT
The symbolic name for an alternate tape. See alternate (ALT) tape.

alternate CRAS
A terminal other than the prime or R/O computer room agent set (CRAS) that is designated to direct and monitor system operations.

alternate dispense mode
In a migration stage in which the FACE table supports 2 different FARF modes, the FARF address type that is not currently being dispensed.

alternate key path
An additional key path other than the primary key path that can be used for searching and accessing data. See also primary key path.

alternate routing
A communications procedure where a message is routed to a substitute receiver when the normal receiver is inoperative or busy.

alternate (ALT) tape
A logical tape to which any currently active output tape may be switched. An alternate tape is also known as an ALT tape.

ALU
Arithmetic and logic unit.

American National Standard Code for Information Interchange (ASCII)
The code developed by ANSI for information interchange among data processing systems, data communications systems, and associated equipment. The ASCII character set consists of 7-bit control characters and symbolic characters.

AML
Acknowledge message label.

AMQ
Application message queue.

AMSG
Application message format.

ANR
Automatic network routing

ANR labels
Automatic network routing labels.

ANR node
Automatic network routing node.

ANSI
American National Standards Institute.

answerback
The input message that acknowledges the successful receipt of a message segment sent to an ALC device.

ANT
Application name table.

API
Application programming interface.

APPC
Advanced Program-to-Program Communications. See TPF Advanced Program-to-Program Communications (TPF/APPC).

application
A function to which a network user may log on. Each application is represented by an application name. Every input message is directed to a particular application. In coupling facility (CF) support, any subsystem, system product, or authorized application running on a TPF system in a multisystem environment or processor configuration. Typically, multiple instances of the application, distributed across the processor configuration, work together to perform a set of functions. For example, a database product could be installed on several systems in the processor configuration. On each system, an instance of the application accesses and manages the data that it shares with the other instances of the application.

application I-stream engine
Any instruction stream engine other than the main I-stream engine in a tightly coupled processor complex. Contrast with main I-stream engine.

application macros
Macros that generate a sequence of inline machine instructions or imbedded macros to perform generalized functions. Contrast with control program macros.

application message format (AMSG)
The prescribed format for messages input to and output from TPF systems.

application message queue (AMQ)
The data structure on which SENDCK macro processing places message blocks that are to be transmitted across an SLC link.

application name table (ANT)
The system table consulted by the communication control program to find the routing control application table (RCAT) pointer for a particular application name.

application program work area
The entry control block (ECB) area reserved for exclusive use by application programs.

application programming interface (API)
The formally defined programming language interface between an IBM system control program or licensed program and its user.

application recovery package (ARP)
A facility that enables users to add additional or different message recovery facilities other than those built into TPF.

application recovery table (ART)
A table used by the application recovery programs that permits users to add additional or different message recovery facilities than those built into TPF systems.

application requester (AR)
A Distributed Relational Database Architecture (DRDA) component that transforms a database request into communication protocols for a distributed relational database system.

application server (AS)
A Distributed Relational Database Architecture (DRDA) component that receives and processes database requests from an application requester.

application set
A collection of programs associated with a particular ECB in that ECB's virtual memory.

Application Support Class Library
A set of C++ classes. The TPF system supports the following subset of Application Support Class Library classes: IBinaryCodedDecimal, IDate, IException, IString, ITime, ITimeStamp, and I0String.

application time-out switch
The switch that is reset every 500 milliseconds by the control program to ensure that ECB-controlled programs are not caught in a tight loop. (Also called the loop protection switch.)

AR
Application requester.

ARB pacing
Adaptive rate-based pacing.

argument
In a function call, an expression that represents a value the calling function passes to the function specified in the call.

arithmetic and logic unit
A part of a computer that performs arithmetic operations, logic operations, and related operations.

arithmetic object
An integral object, a bit field, or objects having the type float, double, or long double.

ARP
Application recovery package.

array
A variable that contains an ordered group of data objects. All objects in an array have the same data type.

array collection
A type of collection with ordered, nonunique elements that are not accessible by key. Elements are ordered by ascending position (index). Elements cannot be inserted or deleted before an existing element.

ART
Application recovery table.

AS
Application server.

ASCII
American National Standard Code for Information Interchange.

assembler language
A symbolic programming language in which the set of instructions includes the instructions of the machine and whose data structures correspond directly to the storage and registers of the machine.

assignment conversion
A change to the form of the right operand that makes the right operand have the same data type as the left operand.

assignment expression
An operation that stores the value of the right operand in the storage location specified by the left operand.

associativity
The order for grouping operands with an operator (either left-to-right or right-to-left).

asynchronous event table (AET)
A record cache subsystem (RCS) control table used to monitor I/O operations that request asynchronous completion notification.

asynchronous messaging
A method of communication between programs in which programs place messages on message queues. With asynchronous messaging, the sending program proceeds with its own processing without waiting for a reply to its message. Contrast with synchronous messaging.

ATA-IATA
Air Transport Association and International Air Transport Association.

attention message
An asynchronous notification mechanism used by DASD caching control units to present the status of an operation requested with the Set Subsystem Mode or Perform Subsystem Function CCWs. A message buffer can be read with the Prepare to Read Subsystem Data order and a Read Subsystem Data command that contains the status of the operation.

attribute
(1) A named property of an entity. A characteristic or property of one or more objects. For example, the attribute for a displayed field could be blinking (OSF). (2) In Extensible Markup Language (XML), additional data included with an element. An attribute must be defined in the schema and can be used with empty elements as well as with elements that contain data. For example, countryCode, areaCode, and pNumber are all attributes of the element PhoneNumber:

<PhoneNumber countryCode="44" areaCode="340" pNumber="635 3343" />
	

automatic network routing (ANR)
In high-performance routing (HPR), a highly effective routing protocol that minimizes cycles and storage requirements for routing network layer packets (NLPs) through intermediate nodes on the route.

automatic network routing (ANR) labels
Labels contained in the network layer header (NHDR) of a network layer packet (NLP) that identify the path of the NLP through the high-performance routing (HPR) network. ANR labels are assigned during the exchange identifier (XID).

automatic network routing (ANR) node
An intermediate node in a high-performance routing (HPR) network that has ANR support applied.

automatic tape mounting
The ability of the tape control program to load and mount alternate (ALT) tapes on devices or convert ALT tapes to active tapes without operator intervention.

auxiliary loader
A program that loads TPF components to a disabled image. The auxiliary loader is capable of loading a complete set of the TPF system software (full load) or selected components (short load). It consists of an offline and online portion. See also E-type loader and general file loader.

available state
The state a coupling facility (CF) is in when all CF commands are processed normally. Contrast with nonavailable state. See coupling facility (CF).