I just had a near-death moment when a critical drive failed for me.
BUT I managed to fix it and this is how I did it (under osx):
Drive (external firewire drive) lost it Volume header and would not mount up. All data was still there but the "index" of the drive was bad.
I tried "Repair Disk" under Disk Utility
The disk tool just said "could not reapait because of an error"
Then I connected the drive using esata, and tried again.
Same, but now could I see more info about the drive anyway.
Then I used the command line tool:
> sudo su
> ls /dev/*disk*
Then I got a list of all connected drives to the computer. I had no idea what drive was who, so I disconnected all drived exept the bad one.
The internal drive of the computer is
so the bad drive should be
then I did:
> fsck_hfs -fr /dev/disk1*
This too failed, but going back and forth the "Repair Disk" under Disk Utility and the fsck command a few times it finally FIXED IT!!! :)
Some of the files got moved to a new folder called "lost+found"
Hope this will help :)