From owner-freebsd-questions@FreeBSD.ORG Tue Jan 6 01:13:53 2004 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id ACF4616A4CE for ; Tue, 6 Jan 2004 01:13:53 -0800 (PST) Received: from smtp3.adl2.internode.on.net (smtp3.adl2.internode.on.net [203.16.214.203]) by mx1.FreeBSD.org (Postfix) with ESMTP id B825C43D4C for ; Tue, 6 Jan 2004 01:13:51 -0800 (PST) (envelope-from malcolm.kay@internode.on.net) Received: from beta.home (ppp129-234.lns1.adl2.internode.on.net [150.101.129.234])i069Djp5087520; Tue, 6 Jan 2004 19:43:47 +1030 (CST) Content-Type: text/plain; charset="iso-8859-1" From: Malcolm Kay Organization: At home To: "Sergey 'DoubleF' Zaharchenko" Date: Tue, 6 Jan 2004 19:43:44 +1030 User-Agent: KMail/1.4.3 References: <20040106002948.38813.qmail@web41102.mail.yahoo.com> <200401061329.26665.malcolm.kay@internode.on.net> <20040106073519.54620420.doublef@tele-kom.ru> In-Reply-To: <20040106073519.54620420.doublef@tele-kom.ru> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Message-Id: <200401061943.44734.malcolm.kay@internode.on.net> cc: scott@sremick.net cc: FreeBSD Subject: Re: "Cannot find file system superblock" error - how to recover? X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Jan 2004 09:13:53 -0000 On Tue, 6 Jan 2004 15:05, Sergey 'DoubleF' Zaharchenko wrote: > On Tue, 6 Jan 2004 13:29:26 +1030 > > Malcolm Kay probably wrote: > > On Tue, 6 Jan 2004 10:59, Scott I. Remick wrote: > > > Sorry for the delay... holidays had me busy. > > Me too:) > > > > Hopefully you're still around > > > and interested in picking up where we left off. I think we're > > > definitely onto something... > > > > Looking back over some of your e-mails I find: > > QUOTE > > su-2.05b# disklabel -r /dev/ad6s1c > > # /dev/ad6s1c: > > 8 partitions: > > # size offset fstype [fsize bsize bps/cpg] > > c: 156344517 63 unused 0 0 # "raw" part= , > > don't edit > > e: 156344517 63 4.2BSD 2048 16384 89 > > partition c: partition extends past end of unit > > disklabel: partition c doesn't start at 0! > > disklabel: An incorrect partition c may cause problems for standard > > system utilities > > partition e: partition extends past end of unit > > > > That doesn't look good. > > ENDQUOTE > > > > The 63 offset is spurious. I've seen this before somewhere but can't > > remember the details -- i.e the value 63. > > I know where you've seen this. The normal offset for the first *slice* > is 63 sectors, for some historical reasons (those extra sectors were to > be used for bad block replacement or something like that). > Yes, I expect it in the output from fdisk. Ignoring for the moment that the BIOS ideas of geometry has nothing=20 to do with the physical reality; all slices start at sector 1 of a track = so having used sector 1 of the first track (cylinder 0 head 0) for the MBR, the fir= st slice must start at cylinder 0 head 1 sector 1; usually an offset of 63 with th= e assumed virtual geometry. (Nothing to do with bad block replacement which on modern drives is almos= t=20 completely hidden) But I have seen the 63 before in corrupted disklabels, not just slice pos= itions. > Not sure how the 63 made it into the disklabel, though. Neither do I. Malcolm Kay