I'm trying to determine the number of tapes that are in the convenience I/O
station of a 3494 tape library.  I thought that I had found the answer on
Richard Sims' QuickFacts page:

3494, count of cartridges in    Via Unix command:
Convenience I/O Station         'mtlib -l /dev/lmcp0 -vqK -s ff10'

However, I'm having trouble getting the mtlib command to produce the
results that I was looking for.  When I run this command, I always get a
count of 0 returned, even when we've just ejected tapes and they are still
in the I/O station.  The same is true if we've just inserted tapes into the
I/O station, and they are still in the process of being stored in the cells.

Am I missing something?  Is the category "FF10" correct for cartridges in
the I/O station?  When I query with other categories, I get the results
that I'm expecting.

Is there a master list of the valid categories for the 3494?

Thanks in advance,

Ted