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 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 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 and 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 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 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  stop-
	      tions.  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 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@metla.fi>.

COPYRIGHT

       The program and the manual page are copyrighted by Kai Makisara, 1998-2001.  They can be distributed according to the GNU Copyleft.

SEE ALSO

       st(4)

								   November 2001							     MT(1)