Tape Volume DEQ at Demount

Tape volume DEQ at demount is not affected by restarts. If restart is from a checkpoint, all volumes that are dequeued during the processing of the job are enqueued when the restart job is initiated. This includes all volumes referenced in the JFCB at the time of checkpoint. Subsequent restart processing tests each tape data set open at the time of checkpoint to determine if:

the data set was open for OUTPUT, OUTIN, EXTEND, OUTINX, or INOUT when the checkpoint was taken.
JFCDQDSP was set to 1 in the JFCB at the time of checkpoint.
the program restarting is APF authorized.

If these conditions are satisfied, the DEQ at demount is reestablished so that the data set's current volume is dequeued when it is demounted. All volume serials in the JFCB and JFCB extensions prior to the current volume are dequeued during the restart process for that data set.

Because all volumes, including those dequeued through the DEQ at demount, are enqueued at restart, if only for a short time, automatic checkpoint/restart may result in a “waiting for volumes” condition if any of the dequeued volumes are allocated to another job. A deferred checkpoint/restart can be timed to avoid such a delay.