TAPEHARDWARECOMPACT and NOTAPEHARDWARECOMPACT: Specifying the data format used when writing to a 3480X tape device

Explanation: TAPEHARDWARECOMPACT | NOTAPEHARDWARECOMPACT are mutually exclusive, optional parameters that specify whether the Improved Data Recording Capability (IDRC) should be used when a 3480X is used as the output device.

IDRC is a form of data compaction that can improve storage capacity for most data sets. The amount of improvement depends upon the data contained within the data set.

TAPEHARDWARECOMPACT specifies that DFSMShsm will request that IDRC be used on eligible 3480 tape cartridges. NOTAPEHARDWARECOMPACT specifies that DFSMShsm will not use IDRC.

The compaction status assigned to a 3480 tape volume occurs at the time the volume is first used for output. This status is determined by the tape unit being used for output and the current specification of SETSYS TAPEHARDWARECOMPACT. DFSMShsm can be directed to use the 3480X device, but not the IDRC feature by specifying the SETSYS NOTAPEHARDWARECOMPACT command. The following table summarizes how the compaction status is assigned to an empty 3480 tape volume:

SETSYS Parameter	Output Unit (3480)	Output Unit (3480X)	Output Unit (3490)	Output Unit (3590-1)
TAPEHWC	No compaction	Compaction	Compaction	Compaction
NOTAPEHWC	No compaction	No compaction	Compaction	Compaction

When output is restricted to a specific unit, the DFSMShsm unit name may change. An empty 3480 cartridge can become a 3480X or 3490 cartridge containing compacted data. An empty 3480 or 3480X cartridge can become a 3490 cartridge containing compacted data.

When output is not restricted to a specific unit, DFSMShsm selects the first available volume. There is no preference between a 3480, 3480X, or 3490 unit. The compaction status assigned to an empty tape volume is based on the following:

The tape unit associated with the tape volume
Whether or not 3480X or 3490 tape units are installed on the system
The SETSYS command parameters TAPEHARDWARECOMPACT or NOTAPEHARDWARECOMPACT

The TAPEHARDWARECOMPACT parameter used with the following unit-restriction parameters causes control unit compaction to be requested:

ABACKUP UNIT(unittype)
ARECOVER TARGETUNIT(unittype)
DEFINE DUMPCLASS(class UNIT(unittype))
SETSYS ARECOVERUNITNAME(unittype)
SETSYS ARECOVERML2UNIT(unittype)
SETSYS ABARSUNITNAME(unittype)
SETSYS BACKUP(TAPE(unittype))
SETSYS CDSVERSIONBACKUP (BACKUPDEVICECATEGORY (TAPE(UNITNAME(unittype)))
SETSYS MIGUNITNAME(unittype)
SETSYS RECYCLEOUT(BACKUP(unittype))
SETSYS SPILL(TAPE(unittype))
SETSYS TAPEMIGRATION(DIRECT(TAPE(unittype)))
SETSYS TAPEMIGRATION(ML2TAPE(TAPE(unittype)))
SETSYS TAPEMIGRATION(NONE(ROUTETOTAPE(unittype)))
SETSYS UNITNAME(unittype)

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 TAPEHARDWARECOMPACT or NOTAPEHARDWARECOMPACT, the DFSMShsm default is NOTAPEHARDWARECOMPACT.