About 6 weeks ago, our hardware guy upgraded  the code on the TS3500 and ATape 
to the latest levels and made some hardware upgrades (details on request).  
Within days we began to have assorted tape mount problems.  Supports initial 
response was to upgrade the TSM level to 5.5.4.2 to avoid a known problem with 
SANDISCOVERY.  So we upgrade to the latest V5R5 level, but we still see 
problems.  So we turn off SANDISCOVERY, and things get quiet; the telltale AIX 
message "RESERVATION CONFLICT".  Support asks us to turn on SANDISCOVERY on 
various Library clients, with no effect until last Friday, when the Library 
Manager goes crazy.  So turn off SANDISCOVERY on the LM and all goes quiet.

Yesterday the CE upgraded the TS3500 to the very latest, and within minutes the 
Library begins refusing to mount tapes, with total disregard to the presence or 
absence of SANDISCOVERY and potentially disastrous effect on LANFREE backups.  
As I see it, from my TSM seat, the common thread here is the AIX message of 
"Reservation Conflict", which points to the hardware changes made.

So after hours of looking at logs and mount messages and traces, which has left 
me groggy, the question is "Is anyone out there seen any difficulty  with the 
software combination of latest version of AIX 5, TSM 5.5, and the TS3500.  
Jeremiah, that's me, has been saying for weeks that the problem lies somewhere 
in the combination of hba, switch, port, and whatever, but management always 
blames TSM.

Pardon my incoherence, but I've been reading logs, etc., for the lastin 15 
hours.