NAME

mt − Tape manipulation program for Archive cartridge tape

SYNOPSIS

mt [ -t tapename] command  [count]

DESCRIPTION

Mt provides a mechanism for the user to give tape positioning and other commands to the Archive cartridge tape.  The -t option introduces the device name of the tape that is to be manipulated.  If the tape name is not specified, mt uses dev/nrar0 (the no-rewind raw cartridge tape device).  If the optional count field is not specified, it is set to 1. 

Here is a list of the commands which apply to the mt command:

infoobtain a list of available commands. 

weofwrite count end-of-file marks. 

fsfspace forward count files. 

eraseerase the tape. 

rewindrewind to beginning of tape (BOT). 

tensiontension the tape. 

statusdisplay the status of the tape (see the example below). 

Note that each time the status command is run, the soft error count and the number of tape stops are reset to zero. 

FILES

/dev/nrar*Raw cartridge tape interface. 

SEE ALSO

archive(4)

EXAMPLE

Suppose you have a tape with three separate tar(1) files on it. Tar does not read to the end-of-file mark, and so a second attempt to tar the tape gives rise to an error message.  You get around this by using mt to skip the file marks, as shown here:

% tar  xvf  /dev/nrar0#  tar the first file off the tape
     . . . messages from tar . . .
% mt  fsf#  skip the file mark
% tar  xvf  /dev/nrar0#  tar the second file off the tape
     . . . messages from tar . . .
% mt  fsf#  skip the file mark
% tar  xvf  /dev/nrar0#  tar the third file off the tape
     . . . messages from tar . . .
% mt  fsf#  skip the file mark
%

The status command to mt displays the status of the tape subsystem, as follows:

% mt status
/dev/nrar0: status = 0xssss, read control reg = 0xrr,
    write control reg = 0xww, soft errors = ee, stops = ss
%

where the numbers in italic are the values from the respective parts of the tape subsystem. 

MESSAGES

usage: mt [ -t device ] command [ count ]
Memory jogger message to remind you how to use mt — you get this message if you type an mt command with no parameters. 

mt: don’t know command cccc
The command cccc was not recognized — type mt  info for a list of the commands it knows about. 

mt: tape didn’t open
Some problem with the tape drive — the driver couldn’t open the tape.

mt: negative repeat count
The count field typed on the command line must be positive. 

mt: ioctl failed, cmd: cccc cnt: nn
The command you typed failed in some way when trying to access the tape drive.  The cccc field is the command you typed, and the nn field is the repeat count for that command. 

mt: ioctl (status) failed
The driver was unable to obtain the status of the tape drive.

7th Edition  —  Revision 1.3 of UniSoft UNIX — 12/15/82