Date: Sun, 23 Sep 2001 12:44:38 +0200 From: Wilko Bulte <wkb@freebie.xs4all.nl> To: Matt Dillon <dillon@earth.backplane.com> Cc: "David W. Chapman Jr." <dwcjr@inethouston.net>, "Chad R. Larson" <chad@DCFinc.com>, "Daniel O'Connor" <doconnor@gsoft.com.au>, j mckitrick <jcm@FreeBSD-uk.eu.org>, freebsd-stable@FreeBSD.ORG, Nuno Teixeira <nuno.mailinglists@pt-quorum.com> Subject: Re: hw.ata.wc && hw.ata.tags && softupdates short question Message-ID: <20010923124438.A9914@freebie.xs4all.nl> In-Reply-To: <200109230246.f8N2k2083827@earth.backplane.com>; from dillon@earth.backplane.com on Sat, Sep 22, 2001 at 07:46:02PM -0700 References: <20010921035414.B75668@dogma.freebsd-uk.eu.org> <XFMail.20010921122607.doconnor@gsoft.com.au> <20010922182052.B16388@freeway.dcfinc.com> <002501c143d0$78fa1b40$fe0c4042@inethouston.net> <200109230246.f8N2k2083827@earth.backplane.com>
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On Sat, Sep 22, 2001 at 07:46:02PM -0700, Matt Dillon wrote: > > : > :As pointed out, its believed that IBM uses capacitors to fix this problem. > > I'm rather skeptical of this. If someone can point out the article > or technical spec then ok, but otherwise it's just rumor. It would take > a fairly large capacitor to hold the input voltages in spec long enough > to write out the cache. > > -Matt A larger cap, absolutely. In days long gone by disk manufacturers used the energy stored in the rotation of the platters to power an emergency head-retract on AC powerfail. Sometimes a small rechargable battery was used. Of course neither of this fits the requirements of a cache flush. The last thing you want to do is write on a disk that is not at nominal rpm. W/ -- | / o / /_ _ email: wilko@FreeBSD.org |/|/ / / /( (_) Bulte Arnhem, The Netherlands To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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