MT(1) User Commands MT(1)

NAME

mt - magnetic tape control

SYNOPSIS

mt [-f tapename] command... [count]

DESCRIPTION

The mt utility sends commands to a magnetic tape drive. If -f
tapename is not specified, the environment variable TAPE is used. If
TAPE does not exist, mt uses the device /dev/rmt/0n.

OPTIONS

The following options are supported:

-f tapename
Specifies the raw tape device.

OPERANDS

The following operands are supported:

count
The number of times that the requested operation is to be
performed. By default, mt performs command once. Multiple
operations of command can be performed by specifying
count.


command
The following available commands that can be sent to a
magnetic tape drive are supported. Only as many characters
as are required to uniquely identify a command need be
specified.

asf
Specifies absolute space to count file number.
This is equivalent to a rewind followed by a fsf
count.


bsf
Back spaces over count EOF marks. The tape is
positioned on the beginning-of-tape side of the
EOF mark.


bsr
Back spaces count records.


bssf
Back spaces over the requested number of
sequential file marks. Sequential file marks are
where the file marks are one right after the
other with no other blocks of any kind between
the file marks. The number argument specifies
how many sequential file marks to which to
space. For example, bssf 4 searches backwards to
the first place where there are 4 sequential
file marks and positions to the BOP side of the
4th file mark.

This command is not supported by all drives.


eof
weof
Writes count EOF marks at the current position
on the tape.


fsf
Forward spaces over count EOF marks. The tape is
positioned on the first block of the file.


fsr
Forward spaces count records.


fssf
Forward spaces the over requested number of
sequential file marks. Sequential file marks are
where the file marks are one right after the
other with no other blocks of any kind between
the file marks. The number argument specifies
how many sequential file marks to which to
space. For example, fssf 4 searches forwards to
the first place where there are 4 sequential
file marks and positions after the 4th file
mark.

This command is not supported by all drives.


load
Requests drive load and thread current media.
Not supported by all drives.


lock
Prevents media removal.


nbsf
Back spaces count files. The tape is positioned
on the first block of the file. This is
equivalent to count+1 bsfs followed by one fsf.


seek
Positions to requested logical tape position.


tell
Gets and prints current logical tape position.


unlock
Allows media removal.

If count is specified with any of the following commands,
the count is ignored and the command is performed only
once.

config
Reads the drives current configuration
from the driver and displays it in st.conf
format. See st(4D) for definition of
fields and there meanings.


eom
Spaces to the end of recorded media on the
tape. This is useful for appending files
onto previously written tapes.


erase
Erases the entire tape.

Some tape drives have option settings
where only portions of the tape can be
erased. Be sure to select the correct
setting to erase the whole tape. Erasing a
tape can take a long time depending on the
device and/or tape. Refer to the device
specific manual for time details.


forcereserve
Attempts to break a SCSI II reserve issued
by another initiator. When this command
completes, the drive is not reserved for
the current initiator, but is available
for use. This command can be only be
executed by those with super-user
privileges.


offline
rewoffl
Rewinds the tape and, if appropriate,
takes the drive unit off-line by unloading
the tape.


release
Re-establishes the default behavior of
releasing at close.


reserve
Allows the tape drive to remain reserved
after closing the device. The drive must
then be explicitly released.


retension
Rewinds the cartridge tape completely,
then winds it forward to the end of the
reel and back to beginning-of-tape to
smooth out tape tension.


rewind
Rewinds the tape.


status
Prints status information about the tape
unit.

Status information can include the sense
key reported by the drive, the residual
and retries for the last operation, the
current tape position reported in file
number, and the number of blocks from the
beginning of that file. It might also
report that WORM media is loaded in that
drive.

EXIT STATUS

0
All operations were successful.


1
Command was unrecognized or mt was unable to open the specified
tape drive.


2
An operation failed.

FILES

/dev/rmt/*
magnetic tape interface

SEE ALSO

tar(1), tcopy(1), ar.h(3HEAD), st(4D), mtio(4I), attributes(7)

BUGS

Not all devices support all options. Some options are hardware-
dependent. Refer to the corresponding device manual page.


mt is architecture sensitive. Heterogeneous operation (that is, SPARC
to x86 or the reverse) is not supported.

June 21, 2007 MT(1)