XMEMOPT parameter: Difference between revisions
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<li>If the Online load module is not APF authorized, the X'02' bit is turned off. </li> | <li>If the Online load module is not APF authorized, the X'02' bit is turned off. </li> | ||
<li>As of Model 204 version 7.6, the X'02' setting is required for [[Performance monitoring and tuning#Offloading Model 204 work to zIIP processors|zIIP processing]]. </li> | <li>As of Model 204 version 7.6, the X'02' setting is required for [[Performance monitoring and tuning#Offloading Model 204 work to zIIP processors|zIIP processing]] and for [[Defining the runtime environment (CCAIN)#Disk buffers and Model 204 storage|allocating Model 204 buffer pool buffers above the bar]]. </li> | ||
</ul></td></tr> | </ul></td></tr> | ||
Revision as of 00:42, 2 February 2017
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
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.
If the Online and CRAM-XDM load modules are not APF authorized, the X'80' bit is turned off. |
| 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 (M204XSVC). |
| 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.
|
| 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 Model 204 cross-memory services. |
Note: VIO is incompatible with IOS Branch Entry and EXCPVR.