The field size containing the size of the object to be sent to the ADSM
server is 64 bits so the max object size is 2(superscript: 64) bytes.  I
don't know of anyone actually running a testcase to prove that...but we
have    successfully created some very large (>90GB) single objects with
our database agents which use the ADSM API .  (The ADSM server can span
tape volumes to store an object so you are not limited by your media
capacity).

Chris Zaremba
TDP Client (formerly ADSM Agent) Development
internet  zaremba AT us.ibm DOT com