HP OpenVMS Systems Documentation

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HP OpenVMS DCL Dictionary

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Defines the default characteristics associated with a specific magnetic tape device for subsequent file operations.

The SET MAGTAPE command is valid for magnetic tape devices mounted with foreign volumes.


SET MAGTAPE device-name[:]



Specifies the name of the magnetic tape device for which the characteristics are to be set. The device must not be currently allocated to any other user.



Specifies the default density for all write operations on the magnetic tape device when the volume is mounted as a foreign tape or as an unlabeled tape.

Valid density values are:

Keyword Meaning
DEFAULT Default density
800 NRZI 800 bits per inch (BPI)
1600 PE 1600 BPI
6250 GRC 6250 BPI
3480 IBM 3480 HPC 39872 BPI
3490E IBM 3480 compressed
833 DLT TK50: 833 BPI
TK50 DLT TK50: 833 BPI
TK70 DLT TK70: 1250 BPI
NOTE: Only the keywords above are understood by TMSCP/TUDRIVER code prior to OpenVMS Version 7.2. The remaining keywords in this table are supported only on Alpha and I64 systems.
TK85 DLT Tx85: 10625 BPI - Cmpt III - Alpha/I64 only
TK86 DLT Tx86: 10626 BPI - Cmpt III - Alpha/I64 only
TK87 DLT Tx87: 62500 BPI - Cmpt III - Alpha/I64 only
TK88 DLT Tx88: (Quantum 4000) - Cmpt IV - Alpha/I64 only
TK89 DLT Tx89: (Quantum 7000) - Cmpt IV - Alpha/I64 only
QIC All QIC drives are drive-settable only - Alpha/I64 only
8200 Exa-Byte 8200 - Alpha/I64 only
8500 Exa-Byte 8500 - Alpha/I64 only
DDS1 Digital Data Storage 1 - 2G - Alpha/I64 only
DDS2 Digital Data Storage 2 - 4G - Alpha/I64 only
DDS3 Digital Data Storage 3 - 8-10G - Alpha/I64 only
DDS4 Digital Data Storage 4 - Alpha/I64 only
AIT1 Sony Advanced Intelligent Tape 1 - Alpha/I64 only
AIT2 Sony Advanced Intelligent Tape 2 - Alpha/I64 only
AIT3 Sony Advanced Intelligent Tape 3 - Alpha/I64 only
AIT4 Sony Advanced Intelligent Tape 4 - Alpha/I64 only
DLT8000 DLT 8000 - Alpha/I64 only
8900 Exabyte 8900 - Alpha/I64 only
SDLT SuperDLT1 - Alpha/I64 only
SDLT320 SuperDLT320 - Alpha/I64 only

Note that tape density keywords cannot be abbreviated.


Writes a tape mark at the current position on the magnetic tape volume.


Requires PHY_IO privilege.

Allows you to skip by file mark or by record.


This tape positioning qualifier is for use on local SCSI tape drives only.
PER_IO (default) Allows a local MK device to use the skip-by-filemarks function. The tape drive must be able to do a SCSI READ POSITION command and report blank check at end-of-data. The IO$M_ALLOWFAST function modifier must be supplied with IO$_SKIPFILE. Otherwise, the tape will skip files using the skip-by-records function.
ALWAYS Allows a local MK device to use the skip-by-filemarks function. The tape drive must be able to support the skip-by-filemarks function, and no modifications should be needed to the IO$_SKIPFILE function.
NEVER Specifies that a local MK device skip only by records. If you use a utility that depends on the semantics of skipping with skip-records, you may also need to use this option because it causes BACKUP or COPY to use the previous positioning.



Displays information about the operations performed on the magnetic tape volume.

/LOGSOFT (default)


Controls whether soft errors on the specified device are to be logged in the error log file. Soft errors are errors corrected by the hardware without software intervention. This qualifier affects only devices that support hardware error correction, such as the TU78 magnetic tape drive. When used with other devices, this qualifier has no effect.


Controls whether data records are automatically compacted and blocked together on a TA90E tape drive. Data compaction and record blocking increase the amount of data that can be stored on a single tape cartridge.

Note that once data compaction or noncompaction has been selected for a given cartridge, that same status applies to the entire cartridge.


Moves a TZK10 tape cartridge to the end of the tape, and then back to the beginning of the tape. Use the /RETENSION qualifier on a regular basis to help maintain the integrity of TZK10 tape cartridges.

The /RETENSION qualifier must be used in conjunction with the /REWIND or /UNLOAD qualifier. The /RETENSION qualifier completes its action before /REWIND or /UNLOAD. Use /RETENSION/REWIND when you want the tape cartridge to remain loaded in the drive. Use /RETENSION/UNLOAD when you want to unload the tape cartridge after the retension operation.

This qualifier only affects TZK10 tape cartridge drives and has no effect on non-SCSI drives.


Requests that the volume on the specified device be rewound to the beginning of the magnetic tape.


Requests that the magnetic tape volume be positioned according to any of the following options:
BLOCK: n Skips the specified number of blocks.
END_OF_TAPE Positions the volume at the end-of-tape (EOT) mark.
FILES: n Skips the specified number of tape marks (not files).

The tape is positioned just past the nth tape mark. If n is negative, the tape is still positioned after the nth tape mark, not before it. If the tape is already positioned immediately after a tape mark, a skip of -1 results in no net movement. (The tape moves to the preceding mark, but is then repositioned to the end of the mark, where it began.) For more information on tape marks and files, see the HP OpenVMS System Manager's Manual.

RECORD: n Skips the specified number of records up to 32767.


Requests that the volume on the specified device be rewound and unloaded.




The MOUNT command in this example mounts a foreign tape on the device MTB1. The SET MAGTAPE command defines the density for writing the magnetic tape at 800 bpi.



The MOUNT command in this example mounts a foreign tape on the device MTA0; the SET MAGTAPE command directs the magnetic tape position to skip four files.

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