MT

NAME
SYNOPSIS
DESCRIPTION
AUTHOR
COPYRIGHT
SEE ALSO

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 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

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.

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 initiator-specified partition size and partition support must be enabled for the drive.

load

(SCSI tapes) Load the tape into 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 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 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)

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 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.

datcompression

(some SCSI-2 tapes) Inquire or set the compression status (on/off) using SCSI commands sent by mt. If the count is omitted the compression status is printed. If the count is zero or "off", compression is disabled. If the count is anything else, compression is enabled. The command uses the SCSI ioctl to read and write the Data Compression Characteristics mode page (15). ONLY ROOT CAN USE THIS COMMAND. The compression can be controlled with the mt command compression with kernels above 1.3.84. This command is not currently included in the default configuration of mt.

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. They can be distributed according to the GNU Copyleft.

SEE ALSO

st(4)