MT(4)

NAME
mt - TM-78/TU-78 MASSBUS mag tape interface

SYNOPSIS
mt0 at mba? drive ? tape mu0 at mt0 slave 0

DESCRIPTION
The TM-78/TU-78 combination provides a standard tape drive interface as described in mtio(4). Only 1600 and 6250 BPI are supported; the TU-78 runs at 125 IPS and autoloads tapes.

DIAGNOSTICS

mu%d: no write ring. An attempt was made to write on the tape drive when no write ring was present; this message is written on the terminal of the user who tried to access the tape.

mu%d: not online. An attempt was made to access the tape while it was offline; this message is written on the terminal of the user who tried to access the tape.

mu%d: can't change density in mid-tape. An attempt was made to write on a tape at a different density than is already recorded on the tape. This message is written on the terminal of the user who tried to switch the density.

mu%d: hard error bn%d mbsr=%b er=%x ds=%b. A tape error occurred at block bn; the mt error register and drive status register are printed in octal with the bits symbolically decoded. Any error is fatal on non-raw tape; when possible the driver will have retried the operation which failed several times before reporting the error.

mu%d: blank tape. An attempt was made to read a blank tape (a tape without even end-of-file marks).

mu%d: offline. During an i/o operation the device was set offline. If a non-raw tape was used in the access it is closed.

SEE ALSO
mt(1), tar(1), mtio(4), tm(4), ts(4), ut(4)

HISTORY
The mt driver appeared in 4.1BSD.

BUGS
If a physical error (non-data) occurs, mt may hang ungracefully.

Because 800 BPI tapes are not supported, the numbering of minor devices is inconsistent with triple-density tape units. Unit 0 is drive 0, 1600 BPI.