How do I determine how many physical slots my 3494 library has?

mtlib -l /dev/lmcp0 -qL - off the top of my head.  I don't' have
a 3494 in my lab environment here.

How do I determine how many tapes are offsite?

That depends if you are using DRM or not.  If you are using DRM
then issue q drm.  If not then maybe q volume access=offsite

How do I determine how many tapes total I have?

q volume - count 'em up.  Or try
select count(*) from volumes - off the top of my head.

How do I determine the average capacity per tape?

q volume


--
Joshua S. Bassi
Joshua S. Bassi
Senior Technical Consultant
Symatrix Technology, Inc.
jbassi AT gloryworks DOT com