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From: jones@fortune.UUCP (Dan Jones)
Newsgroups: net.micro.68k
Subject: Re: Altos 68000 - Random errors on HD1 - Fix
Message-ID: <5579@fortune.UUCP>
Date: Mon, 23-Sep-85 21:07:49 EDT
Article-I.D.: fortune.5579
Posted: Mon Sep 23 21:07:49 1985
Date-Received: Fri, 27-Sep-85 06:58:19 EDT
References: <235@investor.UUCP>
Reply-To: jones@fortune.UUCP (Dan jones)
Distribution: net
Organization: Fortune Systems, Redwood City, CA
Lines: 40
Keywords: Altos 68000 Quantum
Summary: 

Apologies for posting to the net, but my mailer barfed on the address
length.

In article <235@investor.UUCP> you write:
>
>     This problem is random and unpredictable, but it seems to have  a
>     greater  chance  to  appear  as  the  disk  fills.  My drives are
>     running close to 90% of capacity.  Beside the  obvious  HD  error
>     messages  to the console, other signs of the problem are messages
>     from tar that a file has changed size and  lseek  error  messages
>     from the ps command.

First off, there is nothing easy about diagnosing disk related failures. 
Given the above it is possible, but not likely, that you have a termination
problem.  I would try the termination first because it is damn simple.

Since the flux densities are near maximum on the innermost tracks, I would
guess that you have one of the following problems: insufficient shielding
or contrariwise too much sensitivity to radiated noise, improper grounding,
or a controller deficiency in the data recovery circuits.  You should run
a diagnostic program on a reasonable number of blocks (>1000) for a 
reasonable number of iterations (>10) with a random data pattern to verify
the success of any changes you make to the system to correct your problem.
Remember, innermost tracks equate to the highest block numbers on most
systems.  Start with the easy changes, like the termination, and go from
there.  It is quite possible that something as simple as re-seating the
cable connectors may solve your problem.

Good Luck,

Dan Jones	UUCP: {ihnp4,ucbvax!amd70,hpda,sri-unix,harpo}!fortune!jones

"'Tis with our judgments as our watches, none go just alike, yet each
believes his own."  Pope, An Essay on Criticism

-- 
Dan Jones	UUCP: {ihnp4,ucbvax!amd70,hpda,sri-unix,harpo}!fortune!jones

"'Tis with our judgments as our watches, none go just alike, yet each
believes his own."  Pope, An Essay on Criticism