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From: jxh@attain.Teradyne.com (Jim Hickstein)
Newsgroups: comp.periphs
Subject: write restore (drive fault) on Xy451 and funny SMD: help!
Keywords: SunOS SMD errors Xylogics 451
Message-ID: <748@attain.Teradyne.com>
Date: 23 Jul 90 19:18:00 GMT
Organization: Teradyne, Inc. San Jose CA
Lines: 29

I have these old, rather odd, 5-inch SMD drives that I recently
dusted off.  (Actually, they're brand-new, in the box, albeit circa 1985.)
They're AIM DART-130's.  100MB SMD.  In their day, not bad. 
I've got a Xylogics 451 (I think) in my Sun 3/150, and I fabbed up some
A and B cable(s) from twist-n-flat (and just plain flat, but more about
that below).  I'm getting "read restore (drive fault)" and "write restore..."
errors on these drives, as well as an "xy0: error 21 bno 0" when I boot.
Sometimes.

I have reformatted one of the drives since I made proper cables.  It didn't
even format completely with ordinary ribbon cable.  One drive found 22
defects, the other only 3.  These errors are all appearing about two-thirds
of the way across the drive: nothing obvious.  They're spread around.
They seem to be dynamic, i.e. format doesn't find them on a spiral write.
Only accessing files in somewhat random order can elicit the errors.

Can some kind soul at Xylogics (you know who you are: you sent me a FAX about
strapping my 472, for which I thank you; it works very nicely now) or at Sun
tell me what these errors indicate?  Is there something I can change about
the controller strapping or filesystem tuning that will eliminate these
errors?  They don't seem harmful, but one partition (*partition*, mind, not
drive) degenerated into hard ecc errors and crashed the machine, but that was
with the flat A cable.  I think I can live with these messages, but I'd
rather not, if you know what I mean.  Thanks very much.
-- 
RF engineer: "It's close.  But, I suppose you don't know about 'close'".
Software engineer: "Well... You have 'close'.  We have *sometimes*."
Jim Hickstein, Teradyne/Attain, San Jose CA, (408) 434-0822 FAX -0252
jxh@teradyne.com   ...!{amdcad,sun}!teda!attain!jxh