Date   : Wed, 22 Jul 1987 09:36:00 AM
From   : Elliot Mednick <elliot@s34.prime.com>
Subject: Sector crashes on double density driver for Xerox 820

I have a package from Software Publishers Inc. of Arlignton Texas which
converts the 8" floppies of my Xerox 820 from single density to one of seven
formats of double density.  The version I have is dated 15 March 1982.  The
problem is that occasionally and inconsistantly, sectors are wiped out during a
write.  Of course, I don't know this until I try to read them (BIOS error...).
I believe that the hardware headers are wiped out and that the controller
cannot read the sector (DU can't read the bad sectors).  This happens even when
writing one sector at time during a Kermit as well as during extracting and
unsqeezing files.  It seems to happen less often when I use a less dense format
and never when I revert to signle density.  I don't remember this ever working
consistently.

My question, then, is this:  Does anyone know if this can possibly be tied to a
bad release of the BIOS or the controller hardware where an update would fix
the problem (and if so, does this company still exist; there are no sources for
the BIOS - I can't see that software could do this kind of damage)?  Or is
this a media problem (I've been using Sony SSDD, though they may be old). Or
are my drives out of alignment or dirty (I've cleaned the heads; the
freqency of error is apparently the same on both of my drives)?  Is there
anybody out there with this kind of experience?  Should I just give up and
invest in a hard disk (any ST506 controllers out there for the 820)?

Thanks in advance,
Elliot Mednick
Prime Computer, Inc.
617-879-2960 x3608

elliot@s34.prime.com (arpa)
...mit-eddie!primerd!s34.prime.com!elliot (uucp)