Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!uhccux!munnari.oz.au!murtoa.cs.mu.oz.au!ditmela!diemen!tasis!ben
From: ben@tasis.utas.oz.au@munnari.oz (Ben Lian)
Newsgroups: comp.sys.mac
Subject: Re: Hard Disc Failures
Message-ID: <1008@diemen.cc.utas.oz>
Date: 2 Sep 89 01:53:18 GMT
References: <870284@hpcilzb.HP.COM> <3989@csd4.csd.uwm.edu> <19291@mimsy.UUCP>
Sender: root@diemen.cc.utas.oz
Organization: Elec Eng & Comp Sci, Uni of Tasmania, Australia
Lines: 32

In article <19291@mimsy.UUCP> spector@brillig.umd.edu.UUCP (Lee Spector) writes:
>General Description of Problem: Failure to recognize disk at startup - just
>                   got flashing "?" icon.  Booting from floppy showed no
>                   hard-disk icon on desktop. After several power-down /
>                   power-up cycles (disconnecting power cord in between)
>                   functionality returned.  Sometimes this took > 10 cycles
>                   and over night.  During failure the hard disk's light would
>                   flash periodically.  After functionality had returned
>                   the "Apple HD SC Setup" program's "test" function showed
>                   no problems with the hard disk.

This sounds exactly like the problem I used to have with my Rodime 140+ 
external HD, though the causes and the solutions may not be the same.
Half of my problems had to do with Mac Plus 128K ROMs that would not talk
to SCSI devices correctly at boot-time. The other half is due to the HD
itself. The following description assumes that your SCSI hardware is
functioning properly.

When I turn on my HD 'cold', it will very often not spin the platters up to
speed, leaving the heads unlocked (as should be the case). I then have to
turn the drive off, let the platters come to a halt, and then power-up
again. It usually takes quite a few of these cycles to finally get the drive
going. The number of attempts (for me) varies between 1 and 15!!

However, once the drive is nice and warm, I can turn it off, pack it away
and take it home, and then have it power-up with no difficulty at all. Time
after time. Note that the operative word is 'warm'. Hence, I never turn the
drive off overnight unecessarily. That awful word 'stiction' comes to mind.
This _may_ be a normal condition with HDs, because it appears to happen with
most any make of HD assembly.

-- bl