Computer Science
MT(1) MT(1)
NAME
mt - control magnetic tape drive operation
SYNOPSIS
mt [-h] [-f device] operation [count] [arguments...]
DESCRIPTION
This manual page documents the tape control program mt.
mt performs the given operation, which must be one of the
tape operations listed below, on a tape drive. The com-
mands can also be listed by running the program with the
-h option. The version of mt is printed with the -v
option. The path of the tape device to operate on can be
given with the -f or -t option. If neither of those
options is given, and the environment variable TAPE is
set, it is used. Otherwise, a default device defined in
the file /usr/include/sys/mtio.h is used.
Some operations optionally take an argument or repeat
count, which can be given after the operation name and
defaults to 1.
The available operations are listed below. Unique abbre-
viations are accepted. Not all operations are available
on all systems, or work on all types of tape drives.
fsf Forward space count files. The tape is positioned
on the first block of the next file.
fsfm Forward space count files. The tape is positioned
on the last block of the previous file.
bsf Backward space count files. The tape is positioned
on the last block of the previous file.
bsfm Backward space count files. The tape is positioned
on the first block of the next file.
asf The tape is positioned at the beginning of the
count file. Positioning is done by first rewinding
the tape and then spacing forward over count file-
marks.
fsr Forward space count records.
bsr Backward space count records.
fss (SCSI tapes) Forward space count setmarks.
bss (SCSI tapes) Backward space count setmarks.
eod, seod
Space to end of valid data. Used on streamer tape
drives to append data to the logical and of tape.
rewind Rewind the tape.
offline, rewoffl
Rewind the tape and, if applicable, unload the
tape.
retension
Rewind the tape, then wind it to the end of the
reel, then rewind it again.
weof, eof
Write count EOF marks at current position.
wset (SCSI tapes) Write count setmarks at current posi-
tion (only SCSI tape).
erase Erase the tape.
status Print status information about the tape unit.
seek (SCSI tapes) Seek to the count block on the tape.
This operation is available on some Tandberg and
Wangtek streamers and some SCSI-2 tape drives. The
block address should be obtained from a tell call
earlier.
tell (SCSI tapes) Tell the current block on tape. This
operation is available on some Tandberg and Wangtek
streamers and some SCSI-2 tape drives.
setpartition
(SCSI tapes) Switch to the partition determined by
count. The default data partition of the tape is
numbered zero. Switching partition is available
only if enabled for the device, the device supports
multiple partitions, and the tape is formatted with
multiple partitions.
partseek
(SCSI tapes) The tape position is set to block
count in the partition given by the argument after
count. The default partition is zero.
mkpartition
(SCSI tapes) Format the tape with one (count is
zero) or two partitions (count gives the size of
the second partition in megabytes). The tape drive
must be able to format partitioned tapes with ini-
tiator-specified partition size and partition sup-
port must be enabled for the drive.
load (SCSI tapes) Load the tape into the drive.
lock (SCSI tapes) Lock the tape drive door.
unlock (SCSI tapes) Unlock the tape drive door.
setblk (SCSI tapes) Set the block size of the drive to
count bytes per record.
setdensity
(SCSI tapes) Set the tape density code to count.
The proper codes to use with each drive should be
looked up from the drive documentation.
densities
(SCSI tapes) Write explanation of some common den-
sity codes to standard output.
drvbuffer
(SCSI tapes) Set the tape drive buffer code to num-
ber. The proper value for unbuffered operation is
zero and "normal" buffered operation one. The mean-
ings of other values can be found in the drive doc-
umentation or, in case of a SCSI-2 drive, from the
SCSI-2 standard.
compression
(SCSI tapes) The compression within the drive can
be switched on or off using the MTCOMPRESSION
ioctl. Note that this method is not supported by
all drives implementing compression. For instance,
the Exabyte 8 mm drives use density codes to select
compression.
stoptions
(SCSI tapes) Set the driver options bits for the
device to the defined values. Allowed only for the
superuser. The bits can be set either by oring the
option bits from the file /usr/include/linux/mtio.h
to count, or by using the following keywords (as
many keywords can be used on the same line as nec-
essary, unambiguous abbreviations allowed):
buffer-writes buffered writes enabled
async-writes asynchronous writes enabled
read-ahead read-ahead for fixed block size
debug debugging (if compiled into driver)
two-fms write two filemarks when file closed
fast-eod space directly to eod (and lose file
number)
auto-lock automatically lock/unlock drive door
def-writes the block size and density are for
writes
can-bsr drive can space backwards well
no-blklimits drive doesn't support read block
limits
can-partitions drive can handle partitioned tapes
scsi2logical seek and tell use SCSI-2 logical
block addresses instead of device
dependent addresses
sysv enable the System V semantics
stsetoptions
(SCSI tapes) Set selected driver options bits. The
methods to specify the bits to set are given above
in description of stoptions. Allowed only for the
superuser.
stclearoptions
(SCSI tapes) Clear selected driver option bits. The
methods to specify the bits to clear are given
above in description of stoptions. Allowed only
for the superuser.
stwrthreshold
(SCSI tapes) The write threshold for the tape
device is set to count kilobytes. The value must be
smaller than or equal to the driver buffer size.
Allowed only for the superuser.
defblksize
(SCSI tapes) Set the default block size of the
device to count bytes. The value -1 disables the
default block size. The block size set by setblk
overrides the default until a new tape is inserted.
Allowed only for the superuser.
defdensity
(SCSI tapes) Set the default density code. The
value -1 disables the default density. The density
set by setdensity overrides the default until a new
tape is inserted. Allowed only for the superuser.
defdrvbuffer
(SCSI tapes) Set the default drive buffer code. The
value -1 disables the default drive buffer code.
The drive buffer code set by drvbuffer overrides
the default until a new tape is inserted. Allowed
only for the superuser.
defcompression
(SCSI tapes) Set the default compression state. The
value -1 disables the default compression. The com-
pression state set by compression overrides the
default until a new tape is inserted. Allowed only
for the superuser.
sttimeout
sets the normal timeout for the device. The value
is given in seconds. Allowed only for the supe-
ruser.
stlongtimeout
sets the long timeout for the device. The value is
given in seconds. Allowed only for the superuser.
datcompression
(some SCSI-2 tapes) Inquire or set the compression
status (on/off) using SCSI commands sent by mt. If
the count is omitted the compression status is
printed. If the count is zero or "off", compression
is disabled. If the count is anything else, com-
pression is enabled. The command uses the SCSI
ioctl to read and write the Data Compression Char-
acteristics mode page (15). ONLY ROOT CAN USE THIS
COMMAND. The compression can be controlled with the
mt command compression with kernels above 1.3.84.
This command is not currently included in the
default configuration of mt.
mt exits with a status of 0 if the operation succeeded, 1
if the operation or device name given was invalid, or 2 if
the operation failed.
AUTHOR
The program is written by Kai Makisara <Kai.Mak-
isara@metla.fi>.
COPYRIGHT
The program and the manual page are copyrighted by Kai
Makisara, 1998. They can be distributed according to the
GNU Copyleft.
SEE ALSO
st(4)
August 1998 1
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