Write count end-of-file marks at the current position on the tape.
smk
Write count setmarks at the current position on the tape.
fsf
Forward space count files.
fsr
Forward space count records.
fss
Forward space count setmarks.
bsf
Backward space count files.
bsr
Backward space count records.
bss
Backward space count setmarks.
rdhpos
Read Hardware block position. Some drives do not support this. The block number reported is specific for that hardware only. The count argument is ignored.
rdspos
Read SCSI logical block position. Some drives do not support this. The count argument is ignored.
sethpos
Set Hardware block position. Some drives do not support this. The count argument is interpreted as a hardware block to which to position the tape.
setspos
Set SCSI logical block position. Some drives do not support this. The count argument is interpreted as a SCSI logical block to which to position the tape.
rewind
Rewind the tape (Count is ignored).
offline, rewoffl
Rewind the tape and place the tape unit off-line (Count is ignored).
erase
Erase the tape. A count of 0 disables long erase, which is on by default.
retension
Re-tension the tape (one full wind forth and back, Count is ignored).
status
Print status information about the tape unit. For SCSI magnetic tape devices, the current operating modes of density, blocksize, and whether compression is enabled is reported. The current state of the driver (what it thinks that it is doing with the device) is reported. If the driver knows the relative position from BOT (in terms of filemarks and records), it prints that. Note that this information is not definitive (only BOT, End of Recorded Media, and hardware or SCSI logical block position (if the drive supports such) are considered definitive tape positions).
errstat
Print (and clear) error status information about this device. For every normal operation (e.g., a read or a write) and every control operation (e.g,, a rewind), the driver stores up the last command executed and it is associated status and any residual counts (if any). This command retrieves and prints this information. If possible, this also clears any latched error information.
blocksize
Set the block size for the tape unit. Zero means variable-length blocks.
density
Set the density for the tape unit. For the density codes, see below. The density value could be given either numerically, or as a string, corresponding to the "Reference" field. If the string is abbreviated, it will be resolved in the order shown in the table, and the first matching entry will be used. If the given string and the resulting canonical density name do not match exactly, an informational message is printed about what the given string has been taken for.
geteotmodel
Fetch and print out the current EOT filemark model. The model states how many filemarks will be written at close if a tape was being written.
seteotmodel
Set (from the count argument) and print out the current and EOT filemark model. Typically this will be 2 filemarks, but some devices (typically QIC cartridge drives) can only write 1 filemark. Currently you can only choose a value of 1 or 2.
eom
Forward space to end of recorded medium (Count is ignored).
eod
Forward space to end of data, identical to eom.
comp
Set compression mode. There are currently several possible values for the compression mode:
off
Turn compression off.
on
Turn compression on.
none
Same as off.
enable
Same as on.
IDRC
IBM Improved Data Recording Capability compression (0x10).
DCLZ
DCLZ compression algorithm (0x20).
In addition to the above recognized compression keywords, the user can supply a numeric compression algorithm for the tape drive to use. In most cases, simply turning the compression 'on' will have the desired effect of enabling the default compression algorithm supported by the drive. If this is not the case (see the status display to see which compression algorithm is currently in use), the user can manually specify one of the supported compression keywords (above), or supply a numeric compression value.
If a tape name is not specified, and the environment variable TAPE does not exist; mt uses the device /dev/nsa0.
The mt utility returns a 0 exit status when the operation(s) were successful, 1 if the command was unrecognized, and 2 if an operation failed.
The following density table was taken from the 'Historical sequential access density codes' table (A-1) in Revision 11 of the SCSI-3 Stream Device Commands (SSC) working draft, dated November 11, 1997.
Code DescriptionType Description
--------------------------------
NRZI Non return to zero, change on ones R Reel-to-reel
GCRGroup code recording C Cartridge
PE Phase encodedCS Cassette
IMFM Inverted modified frequency modulation
MFMModified frequency modulation
DDSDAT data storage
RLLRun length limited
PRML Partial Response Maximum Likelihood
NOTES
1. Serial recorded.
2. Parallel recorded.
3. Old format known as QIC-11.
5. Helical scan.
6. This is not an American National Standard. The reference is based on
an industry standard definition of the media format.
7. DLT recording: serially recorded track pairs (DLTapeIII and
DLTapeIV(20)), or track quads (DLTapeIV(35) and DLTapeIV(40)).
8. Super DLT (SDLT) recording: 56 serially recorded logical tracks with
8 physical tracks each.
