XMEMOPT parameter

Cross-memory PC options

Summary

Default value: X'02' if M204XSVC is linked into the nucleus; X'00' if M204XSVC is not linked into the nucleus
Parameter type: System
Where set: On User 0's parameter line
Related products: All
Introduced: Model 204 V6.1 or earlier

This parameter sets the Model 204 cross-memory services options that can be invoked during execution of Model 204.

This parameter applies only to z/OS.

The XMEMSVC parameter is used with any of the nonzero settings.

Valid settings of XMEMOPT are:

Setting	Meaning
`X'80'`	Activates CRAM-XDM.
`X'20'`	Use SUSPEND/RESUME instead of WAIT/POST for communication between `Model 204` real subtasks. This option may reduce operating system overhead slightly.
`X'04'`	Forces initialization of cross-memory environment.
`X'03'`	Invokes both Timer PC and IOS Branch Entry.
`X'02'`	Invokes IOS Branch Entry (recommended for z/OS) to handle all database and CCATEMP I/O. If the load module is not APF authorized, the X'02' bit is turned off. As of Model 204 version 7.6, the X'02' setting is required for zIIP processing.
`X'01'`	Invokes Timer PC. Note: As described in the Timer PC section, this bit is automatically turned off as of version 7.4 of Model 204 if your system supports the ECTG instruction.
`X'00'`	Disables Timer PC and IOS Branch Entry.

Note: VIO is incompatible with IOS Branch Entry and EXCPVR.