Date: Mon, 8 Jul 2002 19:53:16 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: Peter Wemm <peter@wemm.org> Cc: Julian Elischer <julian@elischer.org>, John Nielsen <hackers@jnielsen.net>, <hackers@FreeBSD.ORG> Subject: Re: offtopic: low level format of IDE drive. Message-ID: <20020708195133.K19349-100000@patrocles.silby.com> In-Reply-To: <20020708233721.DC2C33808@overcee.wemm.org>
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On Mon, 8 Jul 2002, Peter Wemm wrote: > The thing is, just about all IDE drives more than a few GB or so do 'track > writing' and have no fixed sectoring or sector positioning. ie: each time > you write a single sector to a track, it does a read-modify-write of *THE > ENTIRE TRACK*. This is why we have to have write caching turned on for IDE > The sad thing is that this makes softdep almost completely useless, because > the basic assumption is that sectors that were not explicitly written to > will not be touched. The problem is that this isn't the case, even with > write caching turned off. Writing a single sector causes the drive to > completely rebuild the track and all the sectors on it... in a different So, this basically means that even a journalling filesystem wouldn't be much safer... how about battery backed up controllers - would those provide protection? (I suspect not, but maybe they're more sophisticated than I thought.) Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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