Configuration Best Practices › Practices for Improved Productivity and System Availability › Use a Single Startup Module

Use a Single Startup Module

Use a single startup module for all CA IDMS central versions and specify the runtime parameters for an individual central version as keyword/value pairs in the PARM field on the EXEC statement in the startup JCL.

Business Value:

This practice simplifies maintenance and eliminates the effort involved in creating and applying maintenance to multiple startup modules. Use of keyword/value pairs makes it easy to specify options and see those in effect for a central version simply by looking at the JCL.

Additional Considerations:

You must use startup parameters to identify the CA IDMS central version to be started and the DMCL to be used. You can specify values for these parameters in one of two ways:

• Assembling a #DCPARM macro and linking the resulting module with the CA-supplied startup module (RHDCOMVS)
• Specifying the parameter values in the central version's startup JCL

We strongly recommend using the second approach because it eliminates the need for creating and maintaining a separate startup module for each central version.

To provide startup parameters through JCL, specify them in the PARM field of the central version's EXEC statement. You can specify parameter values either as keyword/value pairs or as positional parameters in specific locations within the PARM field. Not only are keyword/value pairs easier to specify and understand than positional parameters, but only keyword/value pairs support all startup parameters. As an example, the name of the DMCL to use can be specified only as a keyword/value pair and not as a positional parameter.

The following EXEC statement starts CA IDMS system 73 with zIIP enabled, a DMCL of CUSTCV, and a WTO exit of CUSTWTO.

//CVSTART  EXEC PGM=RHDCOMVS,
//      PARM='S=73,ZIIP=Y,WTO=DEVWTOX,DMCL=CVDMCL'

A further means for eliminating tailored startup modules is to avoid linking Write-to-Operator (WTO) and Write-to-Operator-Reply (WTOR) exit routines with the CA-supplied startup module. This can be done either by linking them as stand-alone modules under the names of WTOEXIT and WTOREXIT respectively, or by specifying their load module names as startup parameters as shown in the previous example.

More Information:

For more information about the alternatives for specifying runtime parameters at startup, see System Startup in the CA IDMS System Operations Guide.