[NTLUG:Discuss] Lost partitions, mount points, data????

[Bobby Sanders]

--On Wed, 13 Mar 2002 16:17:17 -0800, "clayton.c.miller" <clayton.c.miller at worldnet.att.net> said:

  CM> To All, I have been trying to dump 'doz for a while but every

...

  CM> Can't boot.  System starts fsck and states it short reads the
  CM> superblock.  Asks if this is a '0' length parition and wants to
  CM> know if I want to repair it.  When I try to run fsck or e2fsck,
  CM> or fsck.ext2 it tells me the superblock is corrupt and suggests
  CM> I enter the following:

  CM> e2fsck -b 8139 <(i interpret this to mean it wants the mount
  CM> pount or dev designation)>

I think your interpretation is wrong.  Try running the command exactly
as instructed.  (You may have to boot from the emergency floppy to do
this but the emergency boot floppy should contain a copy of e2fsck and
you will need to know the device name of the file system,
e.g. /dev/hda1 or wherever your root partition lives.)  According to
Welsh and Kaufman, Running Linux, First Edition (perhaps others),
"Because of the importance of the superblock, the filesystem keeps
backup copies of it at intervals on the filesystem.  Second Extended
Filesystems are divided into 'block groups,' where each group has by
default 8192 blocks.  Therefore there are backup copies of the
superblock at block offsets 8193, 16385 (that's 8193 x 2 + 1), 24577,
and so on. [Their comments on how to find the size of the block groups
omitted.] The command is

e2fsck -f -b offset device

..."  It appears that what the message is telling you is that your
filesystem' block groups default offset is 8139 (unless you have a typo and
it is really at 8193, the default offset).

I was able, several years ago, to rescue a "corrupted superblock" file
system using this command.   YMMV.

Good luck,

Bobby Sanders