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mt - magnetic tape positioning and control
mt { -f | -t } tapedevice command count
[ command [ count ] ... ]
mt is used to position or control the specified magnetic
tape drive supporting the commands listed below. Commands
that support a count field allow multiple operations to be
performed (the rewind, status and offline commands do not
support a count field). mt will output failure messages if
the specified tape drive cannot be opened or if the operation
fails.
The -f option specifies which tape device to use. Use sysconfig
-t to list all tape devices on the filer. -t has the
same effect as -f.
- eof, weof
- Writes count end-of-filemarks beginning at the
current position on tape.
- fsf
- Forward spaces over count filemarks. Positions
the tape on the end-of-tape side of the filemark.
- bsf
- Backward spaces over count filemarks. Positiones
the tape on the beginning-of-tape side
of the filemark.
- fsr
- Forward spaces count records. Positions the
tape on the end-of-tape side of the record(s).
- bsr
- Backward spaces count records. Positions the
tape on the beginning-of-tape side of the
record(s).
- erase
- Erases the tape beginning at the current tape
position. When the erase completes, the tape
is positioned to beginning-of-tape.
- rewind
- Rewinds the tape, positioning the tape to
beginning-of-tape.
- status
- Displays status information about the tape
unit. If you have a nonqualified tape device,
use the following command syntax to access the
tape device before the filer can register the
tape device as a valid clone of a qualified
device:
mt -f device status
After the filer accesses the tape device, you
can use the sysconfig -t command to display
information about the device emulation.
- offline
- Rewinds the tape and unloads tape media.
- diag
- Enables or disables display of diagnostic messages
from tape driver. Enabling diagnostic
messages can be helpful when attempting to
diagnose a problem with a tape device. Specifying
a count of "1" enables display of diagnostic
messages, a count of "0" disables diagnostic
messages. Diagnostic messages are dis_abled
by default.
- eom
- Positions the tape to end of data (end of media
if tape is full).
The following example uses mt to display status information
for the no-rewind tape device, unit zero, highest format
(density):
toaster> mt -f nrst0a status
Tape drive: Exabyte 8505 8mm
Status: ready, write enabled
Format: EXB-8500C (w/compression)
fileno = 0 blockno = 0 resid = 0
To skip over a previously created dump file to append a dump
onto a no-rewind tape device, use the fsf (forward space
file) command:
toaster> mt -f nrst0a fsf 1
In takeover mode, the failed filer has no access to its tape
devices. If you enter the mt command in partner mode, the
command uses the tape devices on the live filer.
na_partner(1), na_sysconfig(1), na_tape(4).
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