Defining and initializing a CICS BAC control file

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Each CICS® region that uses CICS BAC support requires its own unique CICS BAC control file. You define this as a VSAM key-sequenced data set (KSDS) and initialize it using the sample JCL shown in Figure 1. This sample job is also supplied as member CBKDIFIL in the SCBKSAMP data set.

Figure 1. Sample JCL to define and initialize a CICS BAC control file
//CBKDIFIL JOB (accounting informaton)
//* Define a control file as a VSAM KSDS
//*
//DEFINE    EXEC PGM=IDCAMS,REGION=1M 
/* 
//SYSPRINT DD SYSOUT=*
//SYSIN    DD * 
 DEFINE CLUSTER (NAME(hlq.control.file) -
         UNIQUE                 -
         INDEXED                –
         CYL(3 1)               -
         SHR(1)                 -
         RECORDSIZE(2048 32760) -
         KEYS(96 0)             –
         FREESPACE(20 20)       -
         VOLUMES(volume) )      -
        DATA                    -
         (NAME(hlq.control.file.data)  –
         CISZ(32768) )          –
        INDEX                   -
         (NAME(hlq.control.file.index) -
          NOIMBED               -
          NOREPLICATE)
//*
//*  Initialize the newly created data set
//*                                               
//INITFILE EXEC PGM=CBKIFILE,PARM='applid'
//STEPLIB  DD  DISP=SHR,DSN=hlq.SCBKLOAD
//CBKCNTL  DD  DISP=SHR,DSN=hlq.control.file
//SYSPRINT DD  SYSOUT=*
//SYSABEND DD  SYSOUT=*
Note: Edit the sample CBKDIFIL job shown in Figure 1 by substituting your own values for the names shown in bold italic characters. Specify your own names for:
  • The control file KSDS
  • The volume ID, unless you are using SMS-managed volumes, in which case you can omit the volume parameter
  • The applid of the CICS region for which you are defining the data set.
  • The high-level qualifier of the CICS BAC load library.
When a CICS region KSDS has been defined by IDCAMS in the first job step shown in Figure 1, the CICS BAC control file initialization program, CBKIFILE, then initializes the data set in job step 2. This program creates one default CICS region properties object record and one default object record for each of the resource types:
  • File
  • Program
  • TD queue
  • Transaction ID
All these default records have the same identifier, namely $DEFAULT, and they provide default values when object records are being created in the following circumstances:
  • When you are running the file maintenance utility to add records to the CICS region control file and you omit some parameters from an ADD resource_type command. The missing parameter values are taken from the appropriate $DEFAULT record.
  • When the CICS BAC request server is creating a control file record as a result of processing a command from the batch request utility, or the callable API, for an undefined object.
  • When the CICS BAC CICS state monitor detects an undefined object and the CICS region properties record specifies that a control file record is to be created in this situation.
For information about undefined object processing, see the description of the CREATERECORD parameter on the UPDATE REGION command on page CREATERECORD({YES|NO}).

You can update these default object records to set your own default values, using either the file maintenance utility UPDATE commands, or the workstation administration client. To see what parameter values are set in these $DEFAULT records, you can use the file maintenance utility LIST command to get a listing of each record or view the records using the workstation administration client. For information about using the file maintenance utility to maintain a CICS region control file after you have defined and initialized it, see CICS BAC file maintenance utility.


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Timestamp icon Last updated: Monday, 2 December 2013


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