I'm on Ubuntu Lucid. It looks like the partition table on my trusted backup drive has gotten damaged or corrupted (may have been improperly removed before unmounting, maybe). Because this is my backup ...

I'm planning to clone only the small system partition of a 750G disk, and restoring it to an empty 500G disk. There's a large data partition on the 750G disk I don't care about. The question is, how ...