Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!marque!lakesys!macak
From: macak@lakesys.lakesys.com (James Macak)
Newsgroups: comp.sys.mac
Subject: Re: Quantum ROM fix report
Summary: Fix not so dumb?
Message-ID: <1376@lakesys.lakesys.com>
Date: 2 Dec 89 03:46:22 GMT
References: <14618@well.UUCP> <9323@batcomputer.tn.cornell.edu> <20837@mimsy.umd.edu> <27801@dhw68k.cts.com> <32331@auc.UUCP> <89334.141000ALE101@PSUVM.BITNET> <17524@netnews.upenn.edu>
Reply-To: macak@lakesys.UUCP (James Macak)
Distribution: na
Organization: Lake Systems - Milwaukee, Wisconsin
Lines: 43

In article <17524@netnews.upenn.edu> jeff@eniac.seas.upenn.edu.UUCP (Jeffrey M White) writes:
>In article <89334.141000ALE101@PSUVM.BITNET> ALE101@PSUVM.BITNET (Allen Edmiston) writes:
>>In article <32331@auc.UUCP>, rar@auc.UUCP (Rodney Ricks) says:
>>><  Oddly enough, the problem does seem to have "fixed itself" after approx.
>>><1 month of hyperactive, rattling, performance-degrading accesses on my IIcx.

>>>I wonder if it would be a good idea for users who just got the fix to just
>>>let the system sit for a few days and "exercise" itself to get rid of the
>>>performance problem?
>>><-ken
>>>Rodney

(Several lines deleted...)
>  As far as having the drive "exercise" itself and get rid of the problem,
>I would think the exercise would always be run.  I doubt they added a real
>time clock chip and counter to the drive, so that after so many hours
>of operation, it wouldn't do the tests anymore.

Warning: the following is third hand (or worse) info but makes for interesting
reading, if not an explanation of the above observation that the good old
drive rattling stopped a month after the ROM fix was installed...

I recently read a message on FidoNet's EchoMac about the ROM fix.  It implied
that the fix is not as "dumb" as Apple would have us believe.  I thought the
business about the drive "settling down" after a while post fix was a lot of
hokum, but this makes some sense.

The message claimed that the fix checks for abnormal piling up of the
lubricant that is indicated by an off-track error reported by the drive.
Given this indication, the fix causes repeated seeks at that location,
spreading the lubricant.  Eventually, when the lubricant is finally completely
redistibuted uniformly (and stays that way) you get a "settling down" of the
drive.

Again, I am no drive expert and am only passing on some info that I found
interesting.  Take it or leave as as you wish...

Jim

-- 

macak@lakesys.lakesys.com (James Macak)
      << All my own opinions. >>