UNIT: Specifying the type of device

Explanation: UNIT(unittype) is a required parameter specifying the type of unit where the volume can be allocated.

For unittype, substitute the type of DASD or tape unit on which the volume can be allocated.

The following are valid types of DASD units:

3380
3390
9345

The BACKUP, DUMP, and MIGRATE functions use the same types of tape units.

The following are valid types of tape units:

3480
3480X
3490
3590-1

You can substitute an esoteric tape unit defined with the SETSYS USERUNITTABLE command. If you specify an esoteric tape unit name that does not exist in the user unit table, the command fails. If you specify:

3480 or 3480X, you use all the functions of the 3480 Magnetic Tape Subsystem.
3490, you use all the functions of the 3490 Magnetic Tape Subsystem.
3590-1, you use all the functions of the 3590 Magnetic Tape Subsystem.

When you want to add a tape volume to DFSMShsm’s control while using the Improved Data Recording Capability (IDRC) of the 3480X, specify 3480X. If output is restricted to 3480X, this may change the unit name. It will not allow an incompatible change, such as an attempt to change a tape volume from 3480X to 3480, when that tape volume already contains compacted data. See the SETSYS TAPEHARDWARECOMPACT parameter for more information.

When you specify esoteric unit names and when you deal with units that can use the 3480X IDRC, all devices associated with an esoteric name must have the IDRC or none of them can.

Defaults: None.

Note:

If you specify a tape unit for a primary or migration level 1 volume, the ADDVOL command fails.
If you specify a DASD unit for a dump volume, the ADDVOL command fails.
If a DASD volume record already exists for the specified volser, you cannot change the unittype.
You can re-ADDVOL a tape with a different unit type as long as the new one is compatible with the existing device type and the unit type (such as an esoteric) is defined to MVS™ and known to DFSMShsm. To make the unit type known to DFSMShsm, use the SETSYS USERUNITTABLE command.