Hello David,            

I experienced this as well when I first got 3590's installed here. The tapes 
are storing 10GB of adsm compressed data. You probably have compression turned 
on in your adsm clients. 

Once I implemented a high speed backup solution from my adsm clients to my adsm 
server, I turned compression off in my client and , lo, adsm started reporting 
'true' capacity of the 3590 volumes. So far, the maximum I have seen put onto a 
3590 cart is 58.4 GB. 

Best Regards,

Peter Zutenis
Principal Systems Programmer
Philip Morris Information Services Ltd
Moorabbin, Australia.