>PACK in itself may be dangerous here, there is a point during the PACK where the data does not exist on disk, only memory, and if you say the disk overflows and bombs, this may be especially a danger during a PACK.

Really? I thought PACK essentially did a rename of your old table and then copied the non-deleted records to the original name (or at least something similar to that). Hence the need for free space double the size of the original file.

So the data should ALWAYS exist on the disk (being able to find what name it's under may be another story, though).