JCL Requirements and Restrictions on Automatic Restart
To allow an automatic step restart or an automatic checkpoint/restart, you must observe the following rules when preparing the job used in the original execution:
- If a step restart is desired, the RD parameter must be coded to request the restart.
- If a checkpoint/restart is desired, a DD statement for the checkpoint data set must be included in the step that executes the CHKPT macro instruction.
- The EXEC statements in the job must have unique names. (Upon restart, the system searches for the named step.)
- If commands are in the original job, the commands are not reexecuted when restart occurs.
- The DD statement VOL=REF parameter is ignored if restart is attempted from a checkpoint taken when the DD statements are opened out of order and the referenced DD statement requested nonspecific tape volumes.
- When using passed data sets, the same temporary data set name should not be reused after the temporary data set has been deleted.
- If the checkpoint data set is SMS-managed, the automatic class selection (ACS) routine must not override the unit or volume selection.