XMEMOPT parameter

Cross-memory PC options

Summary

Default value

4 if M204XSVC is 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

Description

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). 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
X'00'	Disables Timer PC and IOS BRANCH ENTRY.

Note: VIO is incompatible with IOSBE and EXCPVR.