Well put, Wanda;  in a nutshell, I would add...
consider LTO, in lieu of DLT (ie, NO COLLOCATION) -- okay for diskpool
migration and non-collocated copypool data;
use 3590/9840/9940 for the heavy duty cycle workloads... onsite copies,
collocated data, any workload generating lots of start/stop actions.

Don France
Technical Architect -- Tivoli Certified Consultant
Tivoli Storage Manager, WinNT/2K, AIX/Unix, OS/390
San Jose, Ca
(408) 257-3037
mailto:don_france AT att DOT net

Professional Association of Contract Employees
(P.A.C.E. -- www.pacepros.com)