Date: Sat, 22 Sep 2001 19:40:56 -0700 From: "Chad R. Larson" <chad@DCFinc.com> To: "Brandon S. Allbery KF8NH" <allbery@ece.cmu.edu> Cc: "Chad R. Larson" <chad@DCFinc.com>, freebsd-stable@FreeBSD.ORG Subject: Re: hw.ata.wc && hw.ata.tags && softupdates short question Message-ID: <20010922194056.F16388@freeway.dcfinc.com> In-Reply-To: <168920000.1001209332@vpn45.ece.cmu.edu>; from allbery@ece.cmu.edu on Sat, Sep 22, 2001 at 09:42:13PM -0400 References: <20010921035414.B75668@dogma.freebsd-uk.eu.org> <XFMail.20010921122607.doconnor@gsoft.com.au> <20010922182052.B16388@freeway.dcfinc.com> <168920000.1001209332@vpn45.ece.cmu.edu>
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On Sat, Sep 22, 2001 at 09:42:13PM -0400, Brandon S. Allbery KF8NH wrote: > On Saturday, September 22, 2001 18:20:52 -0700, "Chad R. Larson" > <chad@DCFinc.com> wrote: >+----- >| Years ago, there was a main-frame drive manufacturer who used the >| spindle motor as a generator in the case of a power failure. The >| kinetic energy in the spinning disk pack was converted to >| electricity, so there would be enough energy to flush the cache to >| disk and then park the heads. I think it was Century. You know, >| those drives that looked like small washing machines and had >| removable disk packs? >| >| I wonder if any of the current PC drive manufacturers do (or have >| considered doing) the same thing? >+--->8 > > I'm thinking that that's dubious because of entropy. It might have been > possible to pull it off with older drives if the flush could use a > low-power mode, but modern disks are likely to be a lost cause. Actually, it was the head parking that was the most important. These had removable packs, and if the heads weren't parked before the spindle slowed down enough for the heads to stop flying you got a head crash and a big repair bill. -crl -- Chad R. Larson (CRL15) 602-953-1392 Brother, can you paradigm? chad@dcfinc.com chad@larsons.org larson1@home.com DCF, Inc. - 14623 North 49th Place, Scottsdale, Arizona 85254-2207 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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