The CLOCKxx parmlib member contains values that do the following for each system in a sysplex:

• Specify that the system is to prompt the operator to initialize the time of day (TOD) clock during system initialization.
• Specify the difference between the local time and Greenwich Mean Time (GMT).
• Control the use of the IBM® Sysplex Timer (9037), which ensures accurate sequencing and serialization of events.

The values for CLOCKxx are described in z/OS MVS Initialization and Tuning Reference. When assigning values for a susplex configuration, keep in mind:

• Code ETRMODE YES for each system in the multisystem sysplex that is to use the 9037 Sysplex Timer. Configurations that support ETRMODE NO are XCF-Local mode and Monoplex mode.
• ETRMODE YES causes the system to ignore the OPERATOR parameter.
• If all members of your sysplex will run in LPARs or under VM on the same side of a single physical processor, and you are using a simulated Sysplex Timer, specify SIMETRID (nn) instead of or along with ETRMODE YES. In no case, specify SIMETRID (nn) with ETRMODE NO. The system will assume that the installation does not have any type of Sysplex Timer.

  SIMETRID and OPERATOR PROMPT are mutually exclusive. Specifying both causes the system to reject the CLOCKxx member.

For more information about STPMODE settings, also see Server Time Protocol Planning Guide, which is available at the following URL:

http://www.redbooks.ibm.com/redbooks/pdfs/sg247280.pdf