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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 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  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 previ-
	      ous 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. 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  transla-
	      tion" 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  parti-
	      tion 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 imple-
	      menting 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 key-
	      words (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 ver-
			     sion >= 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 supe-
	      ruser.

       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  den-
	      sity.  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)
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