Restricting tape device selection

When processing tapes, you can restrict device selection to certain devices as discussed in Table 1.

Table 1. Restricting Device Selection
Tape Environment	How to Restrict Device Selection
SMS-managed Tape Library	Restrict device allocation to a particular group of devices by associating them with a data class. For an example of a data class for an SMS-managed tape library, see Define a data class, and also refer to z/OS DFSMS Implementing System-Managed Storage. For general information about defining storage groups, refer to z/OS DFSMSdfp Storage Administration.
Nonlibrary	Restrict allocation to a particular group of tape devices by defining an esoteric unit name for them. An esoteric unit name, specified in the SETSYS USERUNITTABLE command, associates a group of similar devices with a name you define to MVS™. An esoteric group for 3590-1 tape devices must contain all 3590-1 tape devices of the same recording technology; for example, 128-track, 256-track, or 384-track recording capability. An esoteric group for 3490 tape devices must contain all 3490 tape devices of the same recording technology. Emulated tape devices on different hardware must belong to the same category: 3590 Model B, 3590 Model E, 3590 Model H, VTS, or other. An esoteric group for 3480 and 3480X devices can mix devices, but the esoteric group will not use improved data recording capability (IDRC). All devices associated with the esoteric unit name are required to have the 3480X feature if IDRC support is desired. A cartridge mounted at end-of-volume is assigned the esoteric unit name and compaction characteristics of the previous tape. Restrict allocation to a particular group of tape devices by specifying the unittype parameter of the following DFSMShsm tape output commands. ABACKUP agname UNIT(unittype) ARECOVER agname TARGETUNIT(unittype) DEFINE DUMPCLASS(name…UNIT(unittype)) SETSYS ARECOVERML2UNIT(unittype) ABARSUNIT(unittype) ARECOVERUNITNAME(unittype) BACKUP(TAPE(unittype)) CDSVERSIONBACKUP (BACKUPDEVICECATEGORY(TAPE (UNITNAME(unittype)))) RECYCLEOUTPUT(BACKUP(unittype)) RECYCLEOUTPUT(MIGRATION(unittype)) SPILL(TAPE(unittype)) TAPEMIGRATION (DIRECT(TAPE(unittype))) (ML2TAPE(TAPE(unittype))) (NONE(ROUTETOTAPE(unittype))) TAPECOPY ALTERNATEUNITNAME(unittype1, unittype2) TAPECOPY ALTERNATE3590UNITNAME (unittype1, unittype2) You can optionally substitute an esoteric unit name for the unittype parameter in the preceding list to restrict certain tape devices to DFSMShsm’s use.

Note: The distinction in Table 1 between SMS-managed and non-SMS-managed becomes apparent when your storage class ACS routine (based on inputs of data set name, unit type, and jobname) provides DFSMShsm with either a storage class name or null. When a storage class is provided (the request is for SMS-managed storage), the storage group ACS routine determines a storage group, and the data class ACS routine restricts selection within that storage group.

When the storage class ACS routine indicates "no storage class," the request is treated like the "Nonlibrary" case in Table 1.