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 commands can also be listed by running the
program with the -h option. The version of mt is printed with the -v or
--version option. The path of the tape device on which to operate 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 postfix k , M
, or G can be used to give counts in units of 1024, 1024 * 1024, or
1024 * 1024 * 1024, respectively.
The available operations are listed below. Unique abbreviations 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 filemarks.
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 end of tape.
rewind Rewind the tape.
offline, rewoffl, eject
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 position (only SCSI
tape).
erase Erase the tape.
status Print status information about the tape unit. (If the density
code is "no translation" in the status output, this does not
affect working of the tape drive.)
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 initiator-specified partition size and partition
support must be enabled for the drive.
load (SCSI tapes) Send the load command to the tape drive. The drives
usually load the tape when a new cartridge is inserted. The
argument count can usually be omitted. Some HP changers load
tape n if the count 10000 + n is given (a special funtion in the
Linux st driver).
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 density codes to
standard output.
drvbuffer
(SCSI tapes) Set the tape drive buffer code to number. The
proper value for unbuffered operation is zero and "normal"
buffered operation one. The meanings of other values can be
found in the drive documentation or, in the 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
necessary, 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)
no-wait don’t wait until rewind, etc. complete
auto-lock automatically lock/unlock drive door
def-writes the block size and density are for writes
can-bsr drive can space backwards as 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
sili Set the SILI bit is when reading in variable
block mode. This may speed up reading blocks
shorter than the read byte count. Set this option
only if you know that the drive supports SILI and
the HBA reliably returns transfer residual byte
counts. Requires kernel version >= 2.6.26.
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 the 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.
stshowoptions
(SCSI tapes) Print the currently enabled options for the device.
Requires kernel version >= 2.6.26 and sysfs must be mounted at
/sys.
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 compression 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 superuser.
stlongtimeout
sets the long timeout for the device. The value is given in
seconds. Allowed only for the superuser.
stsetcln
set the cleaning request interpretation parameters.
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.Makisara@kolumbus.fi>.
COPYRIGHT
The program and the manual page are copyrighted by Kai Makisara,
1998-2008. They can be distributed according to the GNU Copyleft.
SEE ALSO
st(4)
April 2008 MT(1)