Date: Mon, 17 Feb 1997 23:50:14 +1030 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Cc: msmith@atrad.adelaide.edu.au, hackers@FreeBSD.ORG Subject: Re: File system/disk recovery tools ? Message-ID: <199702171320.XAA11522@genesis.atrad.adelaide.edu.au> In-Reply-To: <199702171214.NAA02971@labinfo.iet.unipi.it> from Luigi Rizzo at "Feb 17, 97 01:14:08 pm"
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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 [[
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