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 or
       --version 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.


       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. (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  ini­
              tiator-specified  partition size and partition sup­
              port must be enabled for 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


              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 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.

       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, 1998-2000.  They can be distributed according to
       the GNU Copyleft.


SEE ALSO

       st(4)


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