This was a really frustrating problem which turned out to have a really simple solution, so I'll share it with people who might be having the same struggle.
You plug in a usb hard disk and try and mount it using:
mount /dev/sda1 /media/usb
or similar. And it doesn't work, not even as root. I think it says you need to specify the filesystem type (which means it doesn't know what to do). You try:
to see what is going on with the hard disk and it says something about the partitions not matching the partition table, partitions extending beyond the end of the disk, physical/logical partitions don't match up or something like that.
Don't specify a partition number, just mount the whole hard disk.
For example, instead of:
mount /dev/sda1 /mount/usb
mount /dev/sda /mount/usb
I spent hours - days
- hunting around for the solution! (And felt a bit humiliated when I realised how simple it was!)
PS, There used to be a "Success story" section on LQ, but I couldn't find it; if this is better in another section, please move it.
PPS, I'm on a public computer and won't have Linux access for a looong time
- if anyone can copy the message that fdisk prints out to help people who are searching for it, that would be a big help.