> > Dudes is there any way of saying how much space is left
> > on a particular tape? I have had a look around but am a
> > bit lost.
> 
> Yeah, run bpmedialist and compare with vmquery.

That answer makes no sense.

Dave, a tape holds as much as it holds, period.

In contrast to a disk (has _exactly_ so many cylinders/tracks/sectors
and is usually not compressed); tapes write varying lengths of data,
separated by gaps of different sizes; usually compressing data with
variability in the data, in its fit in the drive buffer, in the firmware
algorithm on that drive; with unpredictable skips over flawed patches of
tape; and to tape length which is not uniform.  The same tape, written
in the same drive with the same source data can vary; the same tape,
same drive, backing up something different will likely be quite
different.  Throw in the variables and and... well, I've seen a range of
4xxGB to 12xxGB on full SDLT600 tapes, for instance.

An available_media listing with a bunch of full tapes will show you the
variability and give you a rough guide of what to expect from a given
pool and retention (more variability if you use one pool for many/all
types of backups, less if you have pools which handle specific clients
and specific, non-volatile data).

When a tape hits EOM (Simon:  End Of Medium to your question; used to be
End Of Tape by detecting a foil sticker) and NetBackup moves on to
another tape, you have zero space left.  Anything else is an
approximation.