Last night I had a serious problem with my netbook. I'm running Ubuntu on a Dell mini with most of the data on an SD card. Anyway, I think the SD card got messed up when the machine went into hibernation, and when I opened the lid I was getting cryptic messages about the drive not being able to mount. I tried the usual tools, fsck, dumpe2fs, gpart, etc. Nothing doing. Everything that was working for other people wasn't working for me... Kept researching the messages I was getting from the various tools:
Block bitmap for group 1 not in group
Bad Magic Number in Superblock
Disk doesn't contain a valid partition table
etc. etc.
The last one ended up being the clue. Found a utility called TestDisk and it had me fixed up in less than 15 minutes.
http://www.cgsecurity.org/wiki/TestDisk_Step_By_Step
It was able to figure out the partitions based on the good data still on the disk. Then it was just a matter of using the tool to rewrite the partition table and I was back in business!
