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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 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 environ-
       ment 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  avail-
       able 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  past  count file marks, then backward space one file record.  This leaves the tape posi-
              tioned on the last block of the file that is count-1 files past the current file.

       bsf    Backward space count files.  The tape is positioned on the last block of the previous file.

       bsfm   Backward space past count file marks, then forward space one file record.  This leaves  the  tape  posi-
              tioned on the first block of the file that is count-1 files before the current 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 mul-
              tiple 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 car-
              tridge 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 docu-
              mentation 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  neces-
              sary, 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  sup-
                             ports  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 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 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.MakisaraATkolumbus.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)