Dump control program

Facility

Output TCA atCSA

Output Transaction Areas

Output CICS Programs

Output System and Control Tables

Dequeue Dump Facility

Dump Control Exit

1"igure

11.

Closed Routines

Ir---- :;-,

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^Prepare

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Identification

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^Record

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I _I t ^I

I I I

I

Prepare for

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Area Output

I I

I I

I I

I

^{Common Output}

^I

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^Routine

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L ____ :J

Dump control program

~F.RMINAL MANAGEMENT

Terminal Management provides for communication between terminals and user-written application programs through the Terminal Control program. The user selects only the CICS device-dependent submodules wbich pertain to the terminals on his system. Each of the submodules contains the linkage to an access metbod.

The Basic Telecommunications Access Method (BTAM) is used for most terminal data management. The Graphics Access Method (GAM) is used for the support of locally attached 2260's in the ClCS/OS-STANDARD system. The Telecommunications Access Method (TCAM) can be optionally chosen where consolidation of functions is a system requirement or where sharing of devices is desired in the CICS/OS-STANDARD system.

gee the section "System Configuration" for supported devices and features. table entries contain terminal request indicators, status, statistics, identification, and addresses of IIO and related areas.

Reading data from terminals is a function of Terminal Control.

~he user specifies the terminal device characteristics and desired polling interval so that CICS is generated to satisfy his requirements. terminal, processing programs execute a CICS Terminal Control write macro instruction. The translation of output data from EBCDIC to the appr.opriate terminal code is performed if required.

The communication serviceability facilities, which are an optional feature of BTAM, are used in CICS to increase data processing system

transmission facility control functions (those functions which are nermally related to the control of the communication lines) or terminal device-dependent control functions (those terminal functions which are dependent upon device type and access method). Figure 12 shows the functional flow of the Terminal Control program.

~hen TCAM controls communication lines under CICS/OS, those lines are no longer dedicated to the CICS partition/region. The user thus

~as the capability for a single terminal to access multiple programs in separate partitions/regions which are supported by TeAM. TCAM facilities available within the partition/region supported by TCAM include message switching, broadcasting, disk queuing,

checkpoint/restart of the communication network, and TCAM terminal

support~

The following functions ar~ performed

by,

or in conjunction with, Terminal Management in response to CICS macro instructions issued in user-written application programs.

GET TER~INAL STORAGE: Obtains storage for polling activity and for requested read operations.

FRFE TERMINAL STORAGE: Releases unused terminal storage after the completion of output events.

DETERMINE INPUT DATA LENGTH: Computes the length of input data.

EVENT TBRMINA~ION: Provides a "reset poll" for certain terminal devices to service write requests.

I/O ERROR TEST: Provides 1/0 error detection. See the discussion of "Terminal Error Recovery" below.

AUTOMATIC TASK INITIATION: Services requests for automatic task (transaction) initiation from the Transient Data intrapartition data set.

TASK INI~IATION: Requests the initiation of a transaction upon request from a terminal. When an input message is accepted, a task is created to do th~ processing.

~RANSLATION: Translates received data from transmission code to EBCDIC and data to be sent from EBCDIC to the correct transmission code.

LTNE ADVANCE: Scans the Terminal Control Table to make line control information available for analysis.

LINE ANALYSIS: Analyzes the Terminal Control Table line control information to determine which terminal facilities require further action. For example, an indication that a communication line is free could indicate that a polling operation should begin.

ACCESS METHOD SELECTION: Passes control to the appropriate access method-dependent sub module based on the access method specified in the D?HTCT TYPE=LINE macro instruction. For example, when a

ccmmunication line on which there are 2740 Communication Terminals

is found to require action, control is transferred to a Terminal Control submodule which contains the BTAM control logic.

WAIT: Synchronizes the Terminal Control task with all other tasks in the system. When all terminal read and write operations are begun that can be started, and Terminal Control processing is complete, control is returned to the Task Control program to allow dispatching of other tasks.

For purposes of data handling, transactions are considered to be either synchronous or asynchronous. Synchronous transactions entered

~rom a terminal are bandIed directly by the user¹s application program.

Asynchronous transactions entered from a terminal are handled first by a CICS- or user-provided Asynchronous Transaction Input Processing program, which places them bn a direct access queue as a batch. When all data has been received for a batch, the appropriate user-written application program(s) are initiated to process the data asynchronously with other activity on the terminal. Any output to be sent back to the terminal by the application is placed on a direct access queue

The Asynchronous Transaction Input Processor, Asynchronous

Transaction output ProGessor, and supporting functions are optionally generated as the Asynchronous Transaction Processing facility.

Optional user exits are provided:

1. Just prior to initiation of a transaction.

2. Just prior to starting an output event.

3. Following completion of an input event.

For terminal device-dependent control, there is a module for each access method associated with the device type supported by CICS.

Figure 12 shows the functional flow that is common to all terminal device-dependent modules~

INPUT EVENT TREATMENT: Processes a completed input event, including error checking, storage management, translation, and task initiation.

OUTPUT EVENT TREATMENT: Processes a completed output event, including error checking and storage management.

ACTIVITY CONTROL: Examines the control information for each terminal, checking for requested writes, reads, waits, and other Terminal Control macro requests.

INPUT EVENT PREPARATION: Prepares the line for an input event, including storage management.

OUTPUT EVENT PREPARATION: Prepares the line for an output event, including translation.

EVENT INITIATION: Prepares the terminal data event control block and prepares the linkage of terminal device-dependent control to 'the appropriate access method.

The resolution of permanent transmission errors involves both CICS and additional user coding.; CICS cannot arbitrarily take all action with regard to these errors. User application logic may be necessary to properly resolve the problem.

The following sequence of events takes place when a permanent error occurs for a terminal:

1. The terminal is placed in an "out of service" status.

2. The Terminal Abnormal Condition program is attached to the system.

3. The Terminal Abnormal Condition program writes the error data to a destination in Transient Data Control. This destination is to be defined by the user and may be intrapartition,

extrapartition, or not in existence. If the destination is not in existence, the error data is not sent as output by CICS.

4. The Terminal Abnormal Condition program then links to the user-written program (DFHTEP) to allow further terminal-oriented analysis of the error. ~n the Terminal Error program, the user may decide to have the terminal placed in service, have the

line placed in or out of service, have the transaction in process

Dans le document J Program Product (Page 35-39)