The licensing for Gresham is pretty good. I don't have the details but IIRC
it's per Silo used. We've been using it for about 5 years and it works
great. We interface with Library Station on Z/OS wihout a hitch. As for
Library sharing, it does all the work. No need to go through TSM for that,
just configure the drives to ELM and away you go. For that though you have
to use TSM's device driver because library sharing is not supported with the
GenericTape device class, which is what you use with Gresham' AdvanTAPE
driver. The same goes for LanLess backups. Be sure not to use quickloop on a
brocade switch to connect your drives because you will get alot of IO
errors. I have to TSM servers on the same AIX box and they use the same
drives. This setup has been running for over a year with TSM 4.1.3. I use
the same drives on my test box.

When we started we would define the volumes directly in TSM because ELM had
problems managing scratch Tapes. When I converted to TSM' device driver, I
also deleted all my 'empty' tapes in TSM. Haven't had a problem with
overwritten tapes since. Gresham supplies a script to mark used tapes as
non-scratch which I run a few times a day jsut to be sure. It's also easier
this way because you don't have to define volumes for each storage pool.

Guillaume Gilbert
CGI Canada