I've only used the TRY/BUY version of the HP ADSM Server,  But I can tell
you one thing.  Most of the Tech Support people can't answer questions
about the software.  The one problem on HP as apposed to AIX is that the HP
server only supports GENERICTAPE in the Devclass. This forces you to rely
on the hardware to control the compression and the system guesses how much
space is left on the drive based on your estimate of the capacity.