Subject: Re: SCSI Hard drive problems . . .
From: supertimer@aol.com (Supertimer)
Newsgroups: comp.sys.apple2
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Date: 19 Sep 1999 19:54:20 GMT
References: <7s0vn3$gm6@ds2.acs.ucalgary.ca>
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Message-ID: <19990919155420.01532.00002384@ng-bh1.aol.com>



wbdesnoy@acs2.acs.ucalgary.ca (Byron Desnoyers Winmill) wrote:

>One of the (several) problems which I have with my IIgs configuration is a
>finicky SCSI hard drive.  The problem is that I do not know if it is because
>of the controller, or hard drive, or of even deeper problems.
>
>The issue is this, when the hard drive and computer are first started it
>will always start booting GS/OS, get to a particular point, then dump me into
>the monitor.  It does not matter how long I give the drive to spin up, nor
>anything else that I can think of.  (This is the only device on the chain,
>and there is a terminator on the end, but I would assume that this would
>be a problem in detecting the drive, not loading software from it.)
>
>At that point, I turn both the machine and hard drive off, turn the drive
>back on, give it time to spin up, then power on the computer.  All works
>fine.  If the drive is not turned off then on, it will do the same thing.
>
>Has anybody else experienced this?  Or is it time to go hard drive shopping?
>
>Thanks for the help

Hi Byron, it sounds like a "sticktion" problem.  The first time
I encountered this was when I had a IIe and the hard drive
on it exhibited this problem.  Later, when I got my IIGS, the
hard drive I used to use with it also got the problem.  Most
recently, one of the hard drives on my Windows 95 unit is
beginning to show the problem.

It happens intermittently, but when it does, the drive just
hangs.  It often happens at start time, but eventually, the
drives begins to hang at other times.  That's when you need
to replace the drive.

I'd say you still have a great deal of use out of the drive
before the problem reaches the second stage.  At least a
year or two, maybe several.

I think sticktion happens to all hard disk drives eventually.

The reason the problems shows up at start time first is
because that's when the drive begins to exhibit thermal
expansion due to heating up and it has to adjust to
compensate.  If the motor bearings are "sticky" this
process is disrupted.  Later, at the second stage, this
"stickiness" becomes more severe and can hang the
drive even when it is fully warmed up.