I had posted some questions last month regarding problems we encountered
after our upgrade to TSM 4.1 and thought I would pass along what we
found.  We are using AIX 4.3, 3590E's and a 3494.

When issuing the dsmadmc command we received "ANS1033E An invalid TCP/IP
host name was specified".  Resolution was to edit
/usr/tivoli/tsm/client/ba/bin/dsm.sys and add a line for TCPServeraddress
which stated the tsm server name in full.  This was apparently not
necessary under 3.1.

We could not label K tapes.  We had problems with this under 3.1, but it
turned out IBM needed to flick a switch on the drives.  We upgraded the
same day.  We would receive "ANR8750E Volume is incompatible with specified
device type".  IBM had defined the volume range for the K tapes as "K
extended" and should have been defined as just "K".

We also started receiving IO errors on our 3590 tape drives.  This still
persists today, but a microcode fix for the problem is in test at IBM and
is suppose to be released by the end of the month (Hopefully!).  The error
we are receiving is "ANR8302E I/O error on drive RMT1 (/dev/rmt1)
(OP=WRITE, CC=0, KEY=0B, ASC=44, ASCQ=00".