From owner-freebsd-fs Sat Oct 17 11:02:35 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA07550 for freebsd-fs-outgoing; Sat, 17 Oct 1998 11:02:35 -0700 (PDT) (envelope-from owner-freebsd-fs@FreeBSD.ORG) Received: from magicnet.magicnet.net (magicnet.magicnet.net [204.96.116.9]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id LAA07544 for ; Sat, 17 Oct 1998 11:02:34 -0700 (PDT) (envelope-from bill@bilver.magicnet.net) Received: (from uucp@localhost) by magicnet.magicnet.net (8.8.6/8.8.8) with UUCP id NAA20237 for freebsd-fs@freebsd.org; Sat, 17 Oct 1998 13:59:59 -0400 (EDT) Received: (from bill@localhost) by bilver.magicnet.net (8.9.1/8.9.1) id NAA26674 for freebsd-fs@freebsd.org; Sat, 17 Oct 1998 13:48:25 -0400 (EDT) From: Bill Vermillion Message-Id: <199810171748.NAA26674@bilver.magicnet.net> Subject: Re: filesystem safety and SCSI disk write caching In-Reply-To: <19981017191758.A13174@gvr.org> from Guido van Rooij at "Oct 17, 98 07:17:58 pm" To: freebsd-fs@FreeBSD.ORG Date: Sat, 17 Oct 1998 13:48:25 -0400 (EDT) X-Mailer: ELM [version 2.4ME+ PL38 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Guido van Rooij recently said: > On Fri, Oct 16, 1998 at 07:58:17PM +0000, Terry Lambert wrote: > > The errors seen are a result of uncommitted data in the drive cache, > > not power spikes and gremlins. The interaction is well understood, > > and on firm footing unrelated to Stephan King novels. > I always thought a drive will always be able to flush its write cache > to disk, even when power fails. Not all do. The high-end IBM's do/did. They used the inertia of the spinnging platters to generate enough current to flush the buffers to disk. There aren't a lot of drives that do it. With most drives, power off means driving in the dark. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message