How to Change the SYSPROF EXEC

z/VM® provides a default SYSPROF EXEC that can reside in a saved segment or on the system disk or system disk extension. If it resides on a system disk, it must have a file mode number of 2. For better performance, the SYSPROF EXEC should reside in a saved segment. However, if it resides in a saved segment and a user IPLs with INSTSEG NO, the SYSPROF EXEC is not invoked unless a copy also resides on the system disk or system disk extension.

The system profile is shipped as file SYSPROF $EXEC. To change SYSPROF $EXEC you should use the VMSES/E Local Modification procedure. For more information on the VMSES/E Local Modification procedure, see either the z/VM: Installation Guide or the z/VM: Service Guide. This procedure uses the XEDIT command with the CTL option, the VMFEXUPD command and the VMFBLD command to apply an update to the SYSPROF $EXEC file to generate the updated SYSPROF EXEC.

Notes:
  1. The SYSPROF $EXEC is a packed file (1024) on MAINTvrm’s 3B2 disk.
  2. IBM® recommends that you do not compile the SYSPROF EXEC. If you compile the SYSPROF EXEC, your CMS session will be initialized to use the REXX/370 runtime library instead of the CMS REXX runtime library. You must decide if this acceptable.
If the exec resides on a system disk, it can be changed by anyone who has write access to that disk. After the exec has been modified, if the system is to be IPLed as a named system, or if the S-STAT or Y-STAT capability is to be available, the system must be resaved. If the exec resides in a saved segment, the administrator must follow documented procedures for rebuilding and saving the saved segment after making changes to the exec. In any case, all users currently logged on must re-IPL the system or unpredictable results occur. It is recommended, therefore, that any logic in SYSPROF EXEC that changes frequently should be:
  • Put in another exec that is called by the system profile.
  • Placed on a disk other than file mode S or file mode Y.

Modifications to execs that reside on other disks do not necessitate the re-saving of the system and re-IPL by all users. In SYSPROF EXEC, however, you must remember to access the disks these execs reside on.