BEA eLink for Mainframe TCP 3.1 Information Center: Glossary

BEA eLink for Mainframe TCP 3.1 Information Center

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Click a letter in the BEA eLink TCP for IMS glossary index. Or use the Page Down key, the Page Up key, the arrow keys, or the scroll bar to navigate. Please contact us if you encounter a relevant term that was not defined in this glossary.

A 1-8 character name that is exchanged between BEA eLink gateways as part of an authentication mechanism during CONNECT processing.

alternate PCB

A Program Control Block that allows an IMS transaction (MPP) or BMP to write output messages to a destination other than that from which input was received.

See application programming interface.

application programming interface (API)

A set of well-defined programming interfaces (entry points, calling parameters, and return values) by which one software program utilizes the services of another.

-B-

batch message processing (BMP) program

A user-written application program that performs transaction processing in a batch mode in an IMS system. BMPs can obtain input messages from the IMS message queue, can insert output messages into the IMS message queue, and have access to most OS/390 services.

See batch message processing program.

-C-

CHKP (Checkpoint)

An IMS API call that retrieves the first (or only segment) of the next message from the IMS message queue and commits any previous processing (get/put) against the message queue.

CHNG (Change)

An IMS API call that changes (i.e., sets) the destination associated with a program control block (PCB). Subsequent messages inserted into the IMS message queue using the PCB are directed to the specified destination.

See Customer Information Control System.

A software program that makes a request for a service in a client/server architecture.

client request

A request by an IMS client request transaction (MPP) to BEA eLink TCP for IMS for a service provided by remote system.

client request transaction

A user-written IMS application transaction (MPP) that requests a service via BEA eLink TCP for IMS that is offered by a remote system.

client response

The response to a previously issued IMS client request, processed by an IMS client response transaction (MPP).

client response transaction

A user-written IMS application transaction (MPP) that processes the response to an IMS client request for a service offered by a remote system.

client/server model

A systems or application programming model in which servers provide architected services and clients request those services. Some components in the client/server model can function only as servers; others may function only as clients; still others can function both as clients and servers.

CLIENTSHUTDOWN

An option that can be specified in the BEA eLink TCP for IMS configuration file that allows shutdown processing to be initiated by a remote client request, or as a response to a remote client request.

A standard programming language widely used for business applications, especially on IBM mainframe systems.

configuration file

A text file used by BEA eLink TCP for IMS to define the network configuration of BEA eLink gateways and services.

cross-system coupling facility (XCF)

A component of the OS/390 operating system that provides functions to support cooperation between authorized programs running within a sysplex.

Customer Information Control System (CICS)

An IBM transaction processing monitor that runs on IBM mainframe systems.

-D-

See direct access storage device.

direct access storage device (DASD)

Any storage device, such as a hard disk, that offers random access or direct access to the stored data.

See domain name server.

dotted decimal notation

A convention for expressing IP addresses, consisting of a series of 4 decimal numbers (0-255), separated by periods. Example: 123.205.23.99.

domain name server (DNS)

A program that runs on an Internet-connected computer system (called a DNS server) and provides an automatic translation between domain names and IP addresses.

-E-

(No terms starting with the letter "E")

-F-

(No terms starting with the letter "F")

-G-

A software program that allows dissimilar systems to communicate and exchange information. A gateway normally handles communication between systems and performs all necessary protocol translation such that the end applications communicate transparently.

gateway message

A BEA eLink architected data structure used to exchange requests and responses over a TCP/IP link connecting two BEA eLink gateways.

GN (Get Next)

An IMS API call that retrieves the next segment of a multisegment message from the IMS message queue.

GU (Get Unique)

An IMS API call that retrieves the first (or only segment) of a message from the IMS message queue.

-H-

(No terms starting with the letter "H")

-I-

See Information Management System.

IMS message

An IMS-architected data structure used to implement communications between components in an IMS system.

Information Management System (IMS)

An IBM high-performance, high-volume transaction processing monitor that runs on IBM mainframe systems.

inbound session

A logical communications path between BEA eLink TCP for IMS and another (remote) BEA eLink gateway. An inbound session is used by the remote gateway to send client requests to the local (IMS) gateway for processing.

input/output program control block

An API control block used by an IMS transaction to retrieve its input and write output back to the input source (e.g., a terminal).

Interactive System Productivity Facility (ISPF)

An IBM program product used by system and application programmers to manipulate data (edit, browse, copy, etc.) on an IBM mainframe system.

Internet protocol address (IP address)

A numeric value that uniquely identifies a node in a TCP/IP network. IP addresses are usually expressed in "dotted decimal notation", a series of 4 decimal numbers (0-255), separated by periods. Example: 123.205.23.99.

See Internet protocol address.

See input/output program control block.

See Interactive System Productivity Facility.

ISRT (Insert)

An IMS API call used to insert a message segment into the IMS message queue.

-J-

See job control language.

job control language (JCL)

A language used to define and submit batch jobs on an IBM mainframe system.

-K-

(No terms starting with the letter "K")

-L-

Language Environment /370 (LE/370)

An IBM program product which provides common runtime support for a variety of high-level IBM mainframe programming languages, including COBOL, C/C++, and PL/I.

See Language Environment / 370.

A special TCP/IP socket that is dedicated to "listening" for incoming TCP/IP connection requests at a specific port number.

See logical machine ID.

local gateway

The BEA eLink TCP for IMS gateway.

local service name

A 1-16 character name that identifies a service that can be requested by an IMS client transaction.

logical machine ID (LMID)

A symbolic name for a BEA eLink gateway (corresponding to a specific IP address and port combination).

logical terminal (LTERM)

A terminal attached to an IMS system, used by end users to enter transactions and receive responses.

See logical terminal.

-M-

message level

An attribute associated with messages issued by BEA eLink TCP for IMS that classifies each message as informational, error-related, etc.

message log

A dataset (usually allocated on disk) to which BEA eLink TCP for IMS logs all messages issued.

message processing program (MPP)

A user-written application program that processes transactions in an IMS system. MPPs typically confine their I/O operations to the IMS message queue (e.g., retrieving terminal input and writing terminal output) and a database (such as DB2).

message queue

The message storage and retrieval mechanism used by IMS components to exchange messages. For example, end-user input at a terminal causes a message to be placed into the message queue. A transaction retrieves the message (containing the user input) from the message queue.

message segment

IMS messages are made up of "pieces" called message segments. A message can consist of a single segment, or multiple segments. A message segment is the basic unit of I/O when inserting messages into and retrieving messages from the IMS message queue.

See message processing program.

MVS (Multiple Virtual Storage)

An IBM operating system used by IBM mainframe computers.

MVS Console

A terminal device used by the MVS operating system and other software components to display informational and error messages for the system operator. MVS consoles can also be used by the system operator to enter commands or to inquire on and modify system status.

-N-

(No terms starting with the letter "N")

-O-

online transaction processing

A form of data processing in which users at terminals or workstations send messages to application programs that update databases in real time.

An IBM operating system used by IBM mainframe computers.

outbound session

A logical communications path between BEA eLink TCP for IMS and another (remote) BEA eLink gateway. An outbound session is used by the local (IMS) gateway to send client requests to the remote gateway for processing.

-P-

A 1-8 character name that is exchanged between BEA eLink gateways as part of an authentication mechanism during CONNECT processing.

See program control block.

port number

The entity on a TCP/IP host that identifies a logical communications channel and distinguishes one connection from another. A TCP/IP server application "listens" for incoming connection requests at a designated port. A TCP/IP client application initiates a connection with the server by specifying the host's IP address and the server's designated port number.

program control block (PCB)

An IMS API control block used in conjunction with application program I/O (e.g., inserting messages into and retrieving messages from the IMS message queue).

program specification block (PSB)

A control block that defines a transaction processing program (MPP or BMP) to IMS.

The set of "rules" followed by two systems to communicate and exchange information.

See program specification block.

PURG (Purge)

An IMS API call that indicates that insertion of a message into the IMS message queue is complete (that is, there are no additional message segments).

-Q-

(No terms starting with the letter "Q")

-R-

remote gateway

A BEA eLink gateway (TUX, CICS, or IMS) to which a local BEA eLink TCP for IMS gateway is connected.

remote service name

A 1-16 character name that identifies a service offered by a remote system and which can be accessed through a remote gateway.

request phase

The request phase of an IMS client request. IMS client requests are processed in two "phases" - a request phase (in which transaction T1 issues an IMS client request), and a corresponding response phase (in which transaction T2 processes the response to the request).

response phase

The response phase of an IMS client request. IMS client requests are processed in two "phases" - a request phase (in which transaction T1 issues an IMS client request), and a corresponding response phase (in which transaction T2 processes the response to the request).

-S-

A software program that provides a service in a client/server architecture.

server request

A request (issued by a client located on a remote system) for a service provided by an IMS server transaction.

server response

The response to a request (issued by a client located on a remote system) for a service provided by an IMS server transaction.

server response log

A dataset to which BEA eLink TCP for IMS logs all IMS server responses not correlated with a pending IMS server request.

server transaction

A user-written IMS application transaction (MPP) that provides a service that can be requested by a remote client through BEA eLink.

The process of terminating (or "shutting down") a BEA eLink gateway.

The amount of time that BEA eLink TCP for IMS "waits" before polling the IMS message Queue for new work.

The logical end point of a TCP/IP connection. An application accesses a TCP/IP connection through a socket.

socket descriptor

A TCP/IP-assigned number that uniquely identifies a socket and TCP/IP connection. An application must specify the socket descriptor in TCP/IP API calls to identify the socket/connection.

See socket descriptor.

socket number

See socket descriptor.

-T-

See Transmission Control Protocol Internet Protocol.

When a request is sent to a remote system or to an IMS server transaction and no response is received within a specified period of time, the request "times out" and an error is recognized.

See transaction code.

transaction code (TRANCODE)

A name that uniquely identifies a transaction in an IMS environment.

Transmission Control Protocol Internet Protocol (TCP/IP)

An open communications protocol supported by most systems, including UNIX, personal computers, and IBM mainframes. TCP/IP can be used to exchange information between dissimilar computing platforms.

-U-

(No terms starting with the letter "U")

-V-

(No terms starting with the letter "V")

-W-

Write-To-Operator-with-Reply (WTOR)

A persistent message displayed on an OS/390 console which solicits operator input. A system operator replies to the message by entering the associated reply ID and the text of the reply.

See Write-To-Operator-with-Reply.

-X-

See cross-system coupling facility.

-Y-

(No terms starting with the letter "Y")

(No terms starting with the letter "Z")

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Last update: April 13, 1999.