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From: dw@rocksanne.UUCP (Don Wegeng)
Newsgroups: comp.sys.att
Subject: Re: Hard Disk for PC-6300
Message-ID: <214@rocksanne.UUCP>
Date: Thu, 20-Nov-86 09:13:33 EST
Article-I.D.: rocksann.214
Posted: Thu Nov 20 09:13:33 1986
Date-Received: Thu, 20-Nov-86 23:09:42 EST
References: <8519PAX@PSUVMA> <119@hqda-ai.UUCP> <1504@ihlpl.UUCP>
Organization: Xerox: Webster Research Center, Rochester, NY
Lines: 41

In article <1504@ihlpl.UUCP>, psfales@ihlpl.UUCP (Peter Fales) writes:
> > 	The heads should be moved to the landing area
> > before powering down the drive.  On cheap drives, you
> > must run a program to do this.  More expensive drives do
> > this automatically. 
> > 
> > 	If you opt for a drive without this feature, and
> > forget to run the parking program before shutting down,
> > you *WILL* damage your drive.  It may take several
> > occurrances before you start losing files, but every
> > shutdown without prior parking will decrease the
> > reliability of your drive.
> 
> This is news to me, and if drives with this (mis)feature are commonly in
> use it is probably something that should be more widely known.  Most 
> personal computers I am familiar with have a utility for parking the
> disk heads, but the documentation generally indicates that the heads
> only need to be parked if the computer is going to be moved.

I disagree with Peter Fales. Most inexpensive (and maybe expensive too)
winchester disk drive manufacturers coat their platters with a lubercant
so that when the heads land on the surface of the platter it will not
cause damage. If you were to always power down the drive with the heads
over the exact same cylinder then you might over time wear through the
lubercation, at which point you would start damaging the platter surface
(read "head crash"). Most personal computer usage patterns do not result
in this condition.

In general I believe that it is a good practice to park the heads before you
power down a computer, but I don't consider it an absolute necessity.

One thing that *is* worth considering is that PC component manufacturers
design their products for a five year life time, and in fact have no idea
what failure modes are to be expected after that time period. It probably
makes sense to be nice to your disk drive.

/Don
-- 
"So lie to me, but do it with sincerity."     --M. L. Gore  (Depeche Mode)
						
Don Wegeng	Wegeng.Henr@Xerox.COM	seismo!rochester!rocksanne!dw