SYSIDMS Overview

SYSIDMS Parameter File › SYSIDMS Overview

SYSIDMS Overview

You can use SYSIDMS parameters to specify the following:

Physical requirements of the environment, such as the DMCL and database to use at runtime
Runtime directives that assist in application execution
Operating system-dependent file information

For a complete list of the parameters that can be specified, see Parameter Descriptions.

Establishing Site Defaults

Site-specific defaults can be established for all SYSIDMS parameters by assembling a SYSIDMS defaults load module. If it exists, this load module is used at runtime to determine the default values for all SYSIDMS parameters. Defaults may then be overridden in an individual job step by including a SYSIDMS parameter file in the execution JCL.

Creating a SYSIDMS Defaults Load Module

The following example illustrates how to code a SYSIDMS defaults load module. It is a table of 80-character constants, each of which may contain one or more SYSIDMS parameters, as described in Parameter Descriptions. A parameter and its value must be contained within a single 80-character constant, but more than one parameter may appear within a constant. The last constant must have a value of "END SYSIDMS DEFAULTS."

TITLE 'SYSIDMS - Build load module for SYSIDMS defaults'
SYSIDMS START 0
**************************************************************
* Code any SYSIDMS parms that you want to be part of this SYSIDMS
* defaults load module.  This SYSIDMS defaults load module will be
* processed first before trying to process any SYSIDMS parms defined
* in the JCL for any IDMS batch job.
***************************************************************
          SPACE
          DC  CL80'ECHO=ON DMCL=GLBLDMCL'
          DC  CL80'JOURNAL=OFF'
          SPACE
* The following statement is mandatory and must be the last statement
* in the SYSIDMS defaults load module.
          DC  CL80'END SYSIDMS DEFAULTS'
          END

Linking a SYSIDMS Defaults Load Module

The load module must have both a name and an entry point of SYSIDMS. For operating systems that support XA storage, the load module can be linked as AMODE 31, RMODE ANY.

Overriding SYSIDMS Parameter Defaults

SYSIDMS default values can be overridden for an individual job step by including a SYSIDMS parameter file in the execution JCL.

In the following example, the SYSIDMS parameters included in the job stream instruct CA IDMS/DB to use the DMCL LOCLDMCL to execute a job. DBNAME identifies EMPDB as the database to access at runtime, and the QSAM parameters instruct CA IDMS/DB to use the IDMSQSAM look-ahead read facility when accessing EMPSEG.EMPAREA:

//SYSIDMS  DD *
DMCL=LOCLDMCL DBNAME=EMPDB
IDMSQSAM=ON  QSAMAREA=EMPSEG.EMPAREA

In the following example, the SYSIDMS parameters used are typical for a batch job running under the central version:

//SYSIDMS  DD *
DBNAME=EMPDB  NODENAME=SYSTEM90