Date: Mon, 12 Oct 1998 19:10:00 +0200 From: Stefan Eggers <seggers@semyam.dinoco.de> To: Alfred Perlstein <bright@hotjobs.com> Cc: Zach Heilig <zach@gaffaneys.com>, current@FreeBSD.ORG, seggers@semyam.dinoco.de Subject: Re: bitten 3 times already. Message-ID: <199810121710.TAA28992@semyam.dinoco.de> In-Reply-To: Your message of "Mon, 12 Oct 1998 11:23:57 EDT." <Pine.BSF.4.05.9810121113130.13201-100000@porkfriedrice.ny.genx.net>
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> a: 81920 0 4.2BSD 0 0 0 # (Cyl. 0 - 5*) > b: 614400 163840 swap # (Cyl. 10*-48*) > wdc0: unit 0 (wd0): <IBM-DHEA-38451>, LBA, DMA, multi-block-16, sleep-hack > wd0: 8063MB (16514064 sectors), 17475 cyls, 15 heads, 63 S/T, 512 B/S You have 63 sectors/track which makes 945 sectors/cylinder for 15 heads. Taking this into account I'd expect the start cylinder for the swap partition to be somewhere around cylinder 173 and not 10. What I see here is what I'd expect for about 16.000 sectors/cylinder. That's not a reasonable number and I guess the driver thinks it has 16 heads and 1023 sectors/cylinder due to using LBA. It would be interesting to see what disklabel has to say about the geometry. Seeing these numbers I expect them to be totally wrong and not trustworthy. Now when you do a dump the wd driver does *NOT* use LBA but relies on this geometry and uses CHS addressing. Wrong geo- metry and crash dump makes *boom* then. :-( The fix to avoid getting caught by this again (if my theory is right) I think is pretty obvious. During dump use LBA when we use it for the normal disk accesses. And one could put the propper geometry in which would make CHS addressing work in that case unless something forbibs that. And of course in normal use it works as you use LBA all the time and never rely on any geometry. Stefan. -- Stefan Eggers Lu4 yao2 zhi1 ma3 li4, Max-Slevogt-Str. 1 ri4 jiu3 jian4 ren2 xin1. 51109 Koeln Federal Republic of Germany To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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