I am having big problems writing to a Quantum DLT4000.
This drive is attached to an Ultra 2 which was running a
set of dump scripts using ufsdump, writing to the `ultra'
compressed device, `/dev/rmt/0ubn', dumping roughly 41Gb,
well within the capacity of the compression device.

This machine has now become a media server, and the
storage unit is this drive, using the same device file,
but NetBackup is exiting after writing something less
than 40Gb. The bptm log file even shows it reads EOM from
the tape (unless I am sorely mistaken). I can't
understand what is happening. As far as I can see this
shouldn't happen. Has anyone any experience with this
problem?