MT(1)                   COMMAND REFERENCE                   MT(1)



NAME
     mt - magnetic tape manipulating program for workstations

SYNOPSIS
     mt [ -f tapename ] command [ count ]
     mt [ -f tapename ] select [ -b block_size | -m mode | -d
     density | -s speed code | -v ]

DESCRIPTION
     mt is used to give commands to a magnetic tape drive.  If a
     tape name is not specified, the environment variable TAPE is
     used; if TAPE does not exist, mt uses the device /dev/ntc.
     Note that tapename must refer to a raw (not block) tape
     device and should usually refer to a no-rewind device.

     By default mt performs the requested operation once.
     Operations may be performed multiple times by specifying
     count.

     The available commands are listed below.  Only as many
     characters as are required to uniquely identify a command
     need be specified.

     eof, weof
             Write count end-of-file marks at the current
             position on the tape.

     fsf     Forward space count files.

     bsf     Back space count files.

     fsr     Forward space count records.

     bsr     Back space count records.

     rewind  Rewind the tape (Count is ignored.)

     offline, rewoffl
             Rewind the tape and place the tape unit off-line
             (Count is ignored.)

     status  Print status information about the tape unit.
             (Count is ignored.)

     select  Used for setting parameters to non-default values
             for SCSI devices only. (Count is ignored.)

             -b block_size
                      A number of bytes is expected when size is
                      specified. A number can end in b or u,
                      specifying multiplication by 512 or 1024.




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             -m mode   mode is either b, buffered, or, u,
                      unbuffered.  In buffered mode the tape does
                      not wait for output to be completed.

             -d density

                      density is either a SCSI tape density code
                      (see the manual for the SCSI device) or a
                      density in bits per inch.  If supplied with
                      an actual density, mt will look up and
                      determine the corresponding SCSI tape
                      density code, or report an error if it does
                      not understand the density.

             -s speed code

                      mt does not translate the speed code; see
                      the manual for the SCSI device.

             -v       Turns on verbose mode. mt will report the
                      device status before and after parameters
                      are changed.

     fss     Forward space until count sequential file marks are
             found.

     bss     Back space until count sequential file marks are
             found.

     erase   Erase from the current position to the end of the
             tape.  Some drivers will only allow this command at
             BOT.  (Count is ignored.)

     end     Forward space to the end of recorded data.  (Count
             is ignored.)

     tension,  retension
             Retension cartridge tapes, leaving the tape at BOT.
             (Count is ignored.)

EXAMPLES
     To rewind a tape to the beginning, enter

          mt -f /dev/tc rewind

     To set a 9-track tape drive device, /dev/mt6250, to 6250
     bpi, enter

          mt -f /dev/mt6250 select -d 6250 -v

FILES
     /dev/ntc* Cartridge tape interface



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DIAGNOSTICS
     command command not valid
        Command wasn't one of the commands listed above or wasn't
        a unique abbreviation.

     count must be positive
        Count cannot be a negative number.

     can't open tapename
        Mt couldn't open the named tape.  The device doesn't
        exist, the tape wasn't mounted, or the tape was write
        protected against a weof or erase command.

     Other messages describe tape errors.

RETURN VALUE
     [NO_ERRS]      Command completed without error.

     [USAGE]        Incorrect command line syntax. Execution
                    terminated.

     [P_ERR]        A system error occurred. Execution
                    terminated.  See intro(2) for more
                    information on system errors.

CAVEATS
     In some cases, the user must be super-user to change SCSI
     parameters using select.

     If a system has multiple users, the tape unit may need to be
     in an offline state. There are two methods to get the tape
     unit back online. They are:

          Recycle the tape. Then manually remove the tape from
          the drive and remount or
          reinsert it.

     Or, type:


          mt -f /dev/retension

SEE ALSO
     dd(1), ioctl(2), tc(4), and environ(7).











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%%index%%
na:192,108;
sy:300,584;
de:884,2414;3562,2087;
ex:5649,326;
fi:5975,110;
di:6349,730;
rv:7079,444;
ca:7523,877;
se:8400,172;
%%index%%000000000158