My computer is running ubuntu 5.04, with 2 hard disks. and my /dev/hda4 is mounted as /home

I was uploading some stuff to another computer, and then the system freezed, with the habit given by Microsoft, I rebooted the system and then the nightmare began. When it tried to check the file-system, it gave the following error

-------------------------------------------------------------------
e2fsck 1.35 (28-Feb-2004)
e2fsck: Bad magic number in super-block while trying to open /dev/hda4
The superblock could not be read or does not describe a correct ext2 filesystem. If the device is valid and it really contains an ext2 filesystem (and not ufs or something else), then the superblock is corrupt, and you might try running e2fsck with an alternate superblock:
e2fsck -b 8193 <device>
------------------------------------------------------------------
Then I tried "e2fsck -b 8193 /dev/hda4", it still gave me the same error message above.
Then I found this paragraph
-------------------------------------------------------------
A filesystem can be corrupted so it can't be mounted, the result of damage to
the filesystem's superblock. Any attempt to mount it will fail.
The filesystem keeps backups of the superblock.
THere are backup copies of the superblock at block offsets 8193, 16385 (8192 x
2 + 1), 24577 (8192 x 3 +1)

you can check for the size of superblocks with dumpe2fs <device> | more
if the size is different use that in the formula above.
mine is Blocks per group: 32768

you can run e2fsck using a copy of the superblock

e2fsck -f -b <offset> <device>

eg. e2fsck -f -b 16385 /dev/hda1

(taken from 'running linux' by Matt Welsh and Lar Kaufmann)
---------------------------------------------------------------
I first tried 16385 and 24577 to substitute 8193, it didn't work, and I wondered maybe because I am use ext3 and the error message is meant for ext2, they might have different size of superblocks, so I try to use

"dumpe2fs /dev/hda4 | more"

It give me the following error message

--------------------------
dumpe2fs 1.35 (28-Feb-2004)
dumpe2fs: Filesystem revision too high while trying to open /dev/hda4
Couldn't find valid filesystem superblock
--------------------------
And then I have no idea how to continue.


maybe I need some tools for ext3, or any other good tools to rescue my data? Thanks a lot!

you need to boot up a Live CD like knoppix and run fsck on all partitons affected..( / , /home , /boot , etc......let fsck clean up everything first before re-booting.