z/VM: CP Commands and Utilities Reference - z/VM - IBM

DDR
initial designation. On 3480, 3490 (including 3490Es), and 3590 tape devices,
you can change the recording format (the MODE) each time you choose to
write to a tape volume. After you write to a volume, the MODE value returns to
the default value for that particular tape device. If you wish to write to the tape
in a different recording format next time, you must again specify the MODE
value.
The table below specifies the valid and default mode option values for
supported tape devices:
Device Type Valid Device-
Dependent (MODE
nnnn) Option Values
1800 z/VM: CP Commands and Utilities Reference
Valid Device-
Independent (MODE
nnnn) Option Values
3422 1600, 6250 n/a 1600
3480 38K NOCOMP 38K
3480 w/IDRC XF, 38K COMP, NOCOMP 38K
3490 3490C, 3490B COMP, NOCOMP 3490C
3590 n/a COMP, NOCOMP COMP
Device (MODE nnnn)
Default Value
Notes:
1. If you specify a density mode that the tape cannot handle, the control unit
may not return an error condition. In this case, the mode setting is ignored,
and the default control unit setting is used.
2. The 3490 tape devices, models A01, A02, B02, B04, D31, and D32, should
be treated as type 3480 devices. All other 3490 device models should be
treated as type 3490 devices. For a complete breakdown of 3480 and 3490
device types by model number, see ″Chapter 17. Defining I/O Devices″ in
z/VM: CP Planning and Administration.
3. COMP and NOCOMP are device-independent MODE options for
compaction and non-compaction, respectively, for use with either 3480,
3490, or 3590 tape subsystems.
4. On 3480 tape drives only, if you specify both hardware (MODE XF or
COMP) and software (COMPACT) compaction options, the hardware
support takes precedence.
For 3490s, where hardware compaction is the default (MODE 3490C or
MODE COMP), software compaction will take precedence, if specified.
It is recommended that both software compaction and hardware compaction
not be specified for any tape device.
5. Data is always translated into non-compacted form when read from tape.
6. All other tape related commands view a file as a CMS file located on a
minidisk. However, DDR’s definition of a file is anything that is dumped,
restored, or copied by one DDR command. There could be hundreds of
CMS files in just one DDR file.
REWind
rewinds the tape when a function completes.
UNload
rewinds and unloads the tape when a function completes. This is the default.
LEave
leaves the tape positioned at the end of the file when a function completes.
EMSG
allows the user to determine whether to continue after an I/O error on the
INPUT device. The user must respond to the prompt 'DO YOU WISH TO