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).
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.