When your program writes SYSOUT data, the system stores it in spool data sets. During an automatic step restart, JES3 releases the output spool space that the original execution used. After automatic step restart JES allocates new spool spaces.

If a checkpoint/restart occurs, the data sets used during the original execution are kept. If a SYSOUT data set was open when the last checkpoint was taken, it is repositioned to its position at the time the checkpoint was taken.

The checkpoint routine waits until all requested input/output operations are complete, then requests that the job entry subsystem save positioning information. Data written during the restart execution overlays only the data written between the time the last checkpoint was taken and the time the job step terminated abnormally. If a SYSOUT data set is closed at the checkpoint, the data set is not repositioned. If the restart step opens the same data set again, the data written during the restart follows the data originally written. The data set has an implied disposition of MOD.