Explanation: JES2 and JES3 are mutually
exclusive, optional parameters specifying the job entry subsystem
that is used with DFSMShsm.
If you want to use JES3, you must specify the JES3 parameter before
you specify the first ADDVOL command. If you do not, DFSMShsm defaults
to JES2. When DFSMShsm is started in an operating system that has
JES3 and when you do not specify JES3 during DFSMShsm initialization,
an error message is written when DFSMShsm receives the first request
from the JES3 converter (interpreter). If you specify JES3, but the
operating system uses JES2, DFSMShsm is not notified of the error.
DFSMShsm, however, uses the rules that govern pool configuration
for JES3 and one or both of the following situations can occur:
- Some ADDVOL, SETSYS, and DEFINE commands fail if they are issued
when it is unacceptable in a JES3 system.
- Volumes eligible for recall in a JES2 system might not qualify
for the DFSMShsm general pool and, in some cases, are not available
for recall in the JES3 system.
SMS relationship: Parameter has the same
meaning when applied to SMS-managed or non-SMS-managed DASD volumes
or data sets.
SETSYS default: None.
DFSMShsm default: If you do not specify either
parameter on any SETSYS command, the DFSMShsm default is JES2.