Using more than one version of the CICS Type 3 SVC

You might have to use more than one version of the CICS® Type 3 SVC; for example, to test service applied to the DFHCSVC module while using the current version in a production system.

You can run several CICS regions, at different release levels, in the same MVS™ image, with each region using its own version of the CICS SVC. However, if some of those regions use MRO, all regions that use MRO must use the latest CICS Type 3 SVC (DFHCSVC module) and the latest DFHIRP module. For information about using the latest SVC with earlier releases of CICS, see MRO between different CICS releases with a changed SVC number.

To use more than one version of the CICS SVC, either use the DFHCSVCU utility program, or rename the new SVC module in the LPA, and then respecify the SVC in the SVCPARM statements.

You must have authorization to use the DFHCSVCU utility program. For more information about this program, see Installing the CICS SVCs.

To rename the new CICS SVC module, use the renaming facility of ISPF or IEBCOPY, or the TSO command RENAME, renaming the module to a unique name of your choice. Use SMP/E to rename the CICS SVC module in the SDFHLPA library. Use the SMP/E RENAME command to inform SMP/E of the change to the name of the CICS SVC module. Therefore, if you later use SMP/E to apply service to that module, the service is applied to the renamed module in the LPA, and not the DFHCSVC module.

For example, you might want to use an SVC number 255 for a test CICS region, and the default CICS SVC number 216 for your production system:
  1. Create and apply an SMP/E USERMOD to rename the new CICS SVC module: 
    ++USERMOD (umod1).
++VER(C150) FMID(HCI7000).
++RENAME (DFHCSVC) TONAME(newname).
  2. Specify the number 255 for the new CICS SVC version by adding an appropriate statement to the list of SVCPARM statements. That list then reads: 
    SVCPARM 216,REPLACE,TYPE(3),EPNAME(DFHCSVC)
SVCPARM 215,REPLACE,TYPE(6),EPNAME(DFHHPSVC)  [Only required for HPO]
SVCPARM 255,REPLACE,TYPE(3),EPNAME(newname)   [New CICS SVC version]
    The EPNAME parameter for the new CICS SVC specifies the module name, not the CSECT name, for the new CICS SVC module.

    All the SVCPARM statements apply to the same IEASVCxx member of the SYS1.PARMLIB library.

  3. Perform another IPL of MVS to enable all the SVC versions specified in the SVCPARM statements. After you perform another IPL of MVS, you can use both versions of the CICS SVC, provided that both regions do not use MRO concurrently. If both systems use MRO, only the new, latest version of the SVC and the latest DFHIRP module are used by both regions.
  4. In your production system, specify the number of the current CICS SVC in the CICSSVC system initialization parameter. Similarly, in the test system, specify the number of the new CICS SVC version.