Disk ECC error

[Richard Lamson <Lamson@mit-multics.arpa>]

    Date:  9 September 1987 09:27 pdt
    From:  Robert Albano <albano at VAXA.ISI.EDU>

    Does anyone know how to update the bad blocks file in the fep to
    reflect new bad blocks on a 3645's disk.

It's very rare that "new" bad blocks are created on a disk of any type;
the manufacturer's testing is pretty thorough on this count.  Sometimes
disk drivers write blocks with bad ECC and fail to rewrite them then
next time around.  This is what usually causes blocks to go bad.  Thus,
the way to get rid of the blocks is to rewrite them.

There is a LMFS tool to take care of bad blocks in LMFS files, called
LMFS:FIX-FILE.  I believe there is adequate documentation on its use,
and warnings about how not to use it, perhaps in volume 0 of the
Encyclopedia Symbolicorum.  I hope you have a backup copy of the file in
question, since FIX-FILE will sometimes not be able to recover its
contents, and will overwrite the "bad" block with zeroes.

-- Richard

  Mail: Lamson@MIT-Multics.ARPA, Lamson@Multics.MIT.EDU
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