Verifying that a valid checkpoint ID is supplied for restart

The IMS Program Restart Facility checkpoint ID verification exit, IRTUX001, can be used to verify that a valid checkpoint ID has been supplied for a restart.

About this task

Using this exit is optional. If you choose to create it, it must be linked as load module IRTUX001, and it must be available in the STEPLIB of any IMS jobs that should use the exit.

IRTUX001 is only called when IMS Program Restart Facility determines that a job should be restarted, and when AUTOXRST=NO is not specified for the job step. At the point when the exit is called, IMS Program Restart Facility has already determined the checkpoint ID that will be used for restart.

Procedure

Create and run exit IRTUX001.
This exit uses the following input registers:
  • The module must be linked as member IRTUX001 and be present in the STEPLIB of the IMS job.
  • IRTUX001 must be coded to be entered and run in AMODE 31.
  • Registers at entry to the exit are:
    R1
    The address of a standard format parameter list with one parameter. The first parameter is the address of the checkpoint ID that IMS Program Restart Facility plans to use for restart.
    R13
    The address of a save area that should be used by the exit routine.
    R14
    The return address that should be used by the exit routine.
    R15
    The entry point address of the exit routine.
  • Registers at completion of the exit routine must be:
    R13
    The address of the save area that was passed to the exit.
    R14
    The return address that is used to return to IMS Program Restart Facility.