mt -- magnetic tape control

mt magnetic tape control	Command

SYNOPSIS

mt [-f tapename] command [count]

DESCRIPTION

mt issues commands to an SCSI magnetic tape drive.

If you do not specify tapename, mt attempts to use the contents of the TAPE environment variable as a tape device name. If you do not specify tapename or define the TAPE environment variable, mt uses a default device name of /dev/mt (the first tape drive found, in buffered mode, with automatic rewind after a tape operation).

By default, mt performs the requested operation once; by specifying count, mt can perform multiple operations.

Commands

Following is a list of the commands which mt accepts. You must specify only as many characters of a command as necessary to uniquely identify it. The commands in this section accept input from count.

asf

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

bsf

back space over count EOF characters. The tape is positioned on the beginning-of-tape side of the EOF character.

bsr

back space count records.

device

scan the system for SCSI host adapters, and lists the devices. count specifies the type of the device to list:

0        Disk drive
1        Tape drive
2        Printer
3        Processor
4        WORM
5        CD-ROM
6        Scanner
7        Optical
8        Medium changer
9        Communications
99       All devices

The default is 1 (list all tape drives).

eof

write count EOF characters at the current position on the tape.

format

format the tape. Note that not all tape devices support this command.

fsf

forward space over count EOF characters. The tape is positioned on the first block of the file.

fsr

forward space count records.

nbs

back space count files. The tape is positioned on the first block of the file. This is equivalent to count+1 bsf's followed by one fsf.

weof

write count EOF characters at the current position on the tape.

For the following commands, count is ignored:

eom: space to the end of recorded media on the tape. eom is useful for appending files onto previously written tapes.
erase: erase the entire tape.
offline: rewind the tape and, if appropriate, take the drive unit off-line by unloading the tape.
retension: rewind the cartridge tape completely, then wind it forward to the end of the reel and back to beginning-of-tape to smooth out tape tension.
rewind: rewind the tape.
rewoffl: rewind the tape and, if appropriate, take the drive unit off-line by unloading the tape.
status: print status information about the tape unit.
tension: rewind the cartridge tape completely, then wind it forward to the end of the reel and back to beginning-of-tape to smooth out tape tension.

You can abbreviate commands as long as they remain unique. Thus, the command mt rewi is valid, but mt rew is ambiguous and not valid.

EXAMPLES

The following command rewinds the first tape drive and smooths out the tape tension:

mt -f /dev/mt retension

DIAGNOSTICS

Possible exit status values are:

0: Successful completion.
1: An error occurred or mt was unable to open the specified tape drive.
2: Command was unrecognized.

FILES

/dev/*mt* Tape devices (see tape).

NOTES

Not all devices support all options. Some options are hardware dependent.

mt functions with tape drives connected to a SCSI controller which supports the Advanced SCSI Programming Interface (ASPI), as defined by the Adaptec (TM) Corporation, such as the Adaptec (TM) 1542B SCSI adapter. MKS does not supply the ASPI driver, since the implementation of an ASPI driver is hardware dependent.

See tape for a description of the valid SCSI tape device names.