MT(1)							      General Commands Manual							     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 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 parti-
	      tion 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  argu-
	      ment  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  docu-
	      mentation.

       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 key-
	      words 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  stop-
	      tions.  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 stop-
	      tions.  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 compres-
	      sion 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)