Forked address spaces are perceived to be batch jobs by MVS™ allocation. If a forked address space attempts to allocate a data set on a volume that is not mounted, the request either waits (with or without an operator prompt) or it fails. The ALLOCxx parmlib member controls the behavior of allocation requests of this type. If you do not want the request to wait, specify ALLOCxx statements as follows:

VOLUME_ENQ POLICY (CANCEL)
VOLUME_MNT POLICY (CANCEL)

Use this policy so that forked addresses do not go into allocation waits. Be aware that using this policy can disrupt your system, because it will cause a failure rather than a wait.