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