From owner-freebsd-hackers Mon Feb 17 05:21:38 1997 Return-Path: Received: (from root@localhost) by freefall.freebsd.org (8.8.5/8.8.5) id FAA14518 for hackers-outgoing; Mon, 17 Feb 1997 05:21:38 -0800 (PST) Received: from genesis.atrad.adelaide.edu.au (genesis.atrad.adelaide.edu.au [129.127.96.120]) by freefall.freebsd.org (8.8.5/8.8.5) with ESMTP id FAA14513 for ; Mon, 17 Feb 1997 05:21:33 -0800 (PST) Received: (from msmith@localhost) by genesis.atrad.adelaide.edu.au (8.8.2/8.7.3) id XAA11522; Mon, 17 Feb 1997 23:50:15 +1030 (CST) From: Michael Smith Message-Id: <199702171320.XAA11522@genesis.atrad.adelaide.edu.au> Subject: Re: File system/disk recovery tools ? In-Reply-To: <199702171214.NAA02971@labinfo.iet.unipi.it> from Luigi Rizzo at "Feb 17, 97 01:14:08 pm" To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Date: Mon, 17 Feb 1997 23:50:14 +1030 (CST) Cc: msmith@atrad.adelaide.edu.au, hackers@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL28 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk Luigi Rizzo stands accused of saying: > > dd the whole disk off onto a file and mount it on a vnode? You might > > unfortunately is 1.6GB ... I need to find a bigger unit! dd bits of it at a time? 8) > > have to reconstruct the label and such, and using fsck's '-b' option > > actually an annoying thing with fsck -b is that I never know what > to use as an alternate superblock number. 32, says the manpage, is > an alternate superblock, but what are others ? I guess they depend > upon the geometry of the disk... is there a "magic" number that I > can look for ? You mean you didn't write them down when you made your filesystems? 8) Ok, presumably your disklabel is OK. Have a look in /sys/ufs/ffs/fs.h at the superblock layout; it's 8K long, has a fixed checksum, and contains various predictable fields (eg. the last mountpoint). This should let you hunt a copy of it down. > Luigi Rizzo | Dip. di Ingegneria dell'Informazione -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[