UNIT: Designating the output device

Explanation: UNIT(unittype) is an optional parameter specifying the type of tape unit where aggregate backup output files can be allocated. For unittype, substitute the type of tape unit. If this parameter is not specified on the ABACKUP command, the UNIT defaults to the UNIT specified in the ABARSUNITNAME parameter of the SETSYS command.

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.

If you define both 3592-E05 and 3592-J1A to the same esoteric group, the E05 must use the EFMT1 recording format.

You can define a 3592-E05 or 3592-J1A to the 3590-1 generic group. If so, you must ensure drive compatibility or segregation when using the 3590-1 in a non-SMS environment.

When you are specifying esoteric names and dealing with units that can use the 3480X or 3490 Improved Data Recording Capability (IDRC), all devices (or none of them) associated with an esoteric name are required to have the 3480X or 3490 IDRC.

Note: In a tape library environment, SMS ACS routines override this parameter at allocation time.

Defaults: None.