mt



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  environment variable TAPE is set, it is used.  Other-
       wise, 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  past  count  file marks, then backward space one
              file record.  This leaves the tape positioned 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 positioned 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. Posi-
              tioning  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 opera-
              tion 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 par-
              tition  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 sup-
              port 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  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)

              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

              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.

       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 supe-
              ruser.

       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 sec-
              onds. 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 opera-
       tion 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,
       1998-2005.  They can be distributed according to the GNU Copyleft.


SEE ALSO

       st(4)



                                  August 2005                            MT(1)

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