XL-400 Tape Problems

[Palter@STONY-BROOK.SCRC.Symbolics.COM (Gary M. Palter)]

    Date: Mon, 21 May 90 08:41 EDT
    From: SUHLER@IBM.COM (Paul Suhler)

    For several months, we've had continual problems with the QIC-100 tape
    drive in our XL-400.  Typical problems include write errors, CRC errors,
    and a SCSI error called "Sense Key 0xA7 Extended".  We've been through
    five or six drives and a couple of I/O boards.  The problem never goes
    away for more than a week.

    The Symbolics SE is unable to any diagnosis and can only swap boards.
    I've talked to a couple of people at Symbolics and they haven't found
    anything yet.  It was a drive person at 3M (who makes the XL-400's
    drive) who told me that "sense key A7" indicates the tape has no bad
    blocks information written on it.  Since this error recurred after a
    tape was tested and reformatted by 3M, I wonder whether the error is
    being correctly reported.

    We've attached an Apple SCSI tape drive to the XL-400; it NEVER has
    problems.

    So, my questions:

    1)  Have you had these sorts of chronic problems?  If so, what were the
    cause and cure?  Could it be loss of adjustment by the drive?

    2)  Does anyone suspect bad tapes from 3M?  We use the Gammamat
    pre-formatted ones, of course.

    3)  Is the 3M drive used by Symbolics more finicky than the Apple drive?
    Does it do more testing of the tape at insertion?

The drive used in the XL400 is the same drive used by Apple.

    Thanks for anything that you can tell me.

    Paul Suhler
    Hybrid Dataflow Systems
    IBM Watson Research Center