I ran a long erase with the DLT 8000 drive on the DLT 4000 format tapes over
the holiday weekend to determine if it would give me the DLT 8000 capacity
on the tapes. Well, it didn't work. I ran a test backup on the set and i
am only getting 40GB per tape.

Is there any other way to format the tapes to get the DLT 8000 capacity out
of them?