Path: utzoo!dciem!nrcaer!scs!spl1!ll1a!cej
From: cej@ll1a.UUCP (Jones)
Newsgroups: comp.sys.mac
Subject: Re: disk squeak
Message-ID: <2757@ll1a.UUCP>
Date: 9 Aug 88 17:33:46 GMT
Article-I.D.: ll1a.2757
References: <5635@batcomputer.tn.cornell.edu> <61185@sun.uucp> <2937@utastro.UUCP> <531@motsj1.UUCP>
Distribution: comp
Organization: AT&T, Lisle, Il.
Lines: 54
Summary: it depends

In article <531@motsj1.UUCP>, rnv@motsj1.UUCP (Ron Voss) writes:

> I read somewhere that in the absence of the brush, the static
> discharges through the bearings, and is not "dangerous" to your
> data.  Anyone know for sure?

	It depends.

	It depends on how much static the platters of *your* drive
will build up.  It depends on just how conductive the lubrication of
*your* drive's bearings is, which can depend on the age of the
drive.  And it depends how much of a charge can be on the platters
of *your* drive before it disturbs the R/W  circuitry.

	From my experience (8 years of hardware support on AT&T, HP,
DEC, and CDC products) on literally hundreds of hard drives of all
sizes and shapes, I can say, that, yes, it is true, you can
*sometimes* remove the spindle ground on some drives and they still
work fine.  And, yes they are *often* the cause of the "squeak"
noise on small hard disks.  (Anything used with a Mac is "small" in
my mind. "Big" drives are always free standing.)

	*HOWEVER*, some drives fail constantly without the ground,
while the exact type and model of drive, two feet away, works fine
without it. 

	And, the fact a drive that works without the ground today
does *NOT* mean that it will continue to in the future.  (Yes, I
have seen several examples of this.)  And while you can "read-only"
test the drive after you remove the ground, once it is in use, it's
first failure could well be on a write.  (Though static is far more
likely to affect a read operation.)

	In short: Don't remove it, it's a bad idea.


[ Two other ways of looking at it:

    1.  If it was just a useless hunk of metal, the
	"bean-counters" would have removed it from at least *some*
	of the drives on the market.  They all ground the spindle in
	some manner.

    2.  You back-up your hard drive, right?  And, if you don't wear
	a ground strap, you at least discharge yourself before you
	play with your memory chips, right?  Think of the spindle
	ground as something in the same class.  You *may* not need
	it, but if you, you *don't* want to find out the hard way. ]



...ll1a! cej		[Just me, not AT&T]		Llewellyn Jones

		HASA Qualified - U.S. Approved