SUMMARY:8mm tape drive will not accept a tape

Date: Tue Apr 21 1992 - 19:05:44 CDT

Sun Managers,

Here is my summary of the 8mm tape drive that will not accept a tape.
The summary is at the end of the original message.

--------------------Original Message--------------------------------
My configuration:

sun 4/470
        64meg-256meg memory
        SunOS 4.1.2
        QIC 24
        Exabyte 8200
        sd0: Sun 1.3G (All OS)
        sd2: Maxtor P1-17S
        sd4: Maxtor P1-17S
        sd6: Maxtor P1-17S

The problem is that the 8mm tape drive gets in a state where it will not
accept a tape, any tape. Each time the tape is loaded into the drive, the
drive ejects it.

This will normally occur on one or two systems after the dump script has
run. /var/adm/messages will sometimes show "SCSI bus reset messages."
We have found two ways to recover from this state, 1) reboot, 2)
power cycle the tape drive.

mt -f /dev/rst0 status returns "no tape loaded or drive off line"

The dump script does nothing special, just mt commands, and dump commands.
The last command if mt -f /dev/rst0 rew. I have not seen the drive fail
in the middle of a dump.

I have seen this on more than one system, so I do not expect hardware.

Below is an extract of messages.

Please send replys to:

I will summarize

---------------------End Original Message---------------------------

Thank you for your quick reply to my question. I recieved numerous suggestions
and ideas including:

        clean the drive
        try new tapes
        try old tapes, because Sony made a change to the leader length on
           newer tapes.
        Check SCSI cable lengths
        Switch from video tapes to data tapes
        Read/Write board may need to be replaced
        tape head may need to be replaced
        mole motor may need to be replaced
        use standard device /dev/rst1
        use the mt "offline" command

The proper answer for my problem was submitted by Jon Mellot, He suggested that I check the PROM levels of my

It seems that when Exabyte sells a drive to a vender, they do not know how
it is going to be used. So they put a generic set of PROMs in the device.
This set of PROMs just does not work well with SunOS, and UNIX in general.

The error that we are seeing is called a "servo system" error. The only way
to clear this is to reboot, or to power cycle the drive. The new level of
PROM will also allow a "soft servo" reset by pressing the eject button
while the tape door is open. Also, the new level of PROM will help prevent
this problem from occuring in the future.

The new PROMs have not arrived yet, but if they function as advertised, they
will solve our problem. If the PROMs do not solve our problem, I will write
another summary.

The old PROM levels were:
        SVPROM B019
        MXPROM 425A

The NEW PROM levels are:

        SVPROM C034
        MXPROM 2618

Again thanks to those who responded:

Tom Haynes
GE Aerospace.

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