What you see depends on the original data.
Aix is an example where you can get very good compression on 9840.
In fact when we were doing our testing on os390 one of my colleagues wrote a
little program just to exercise the tape decks which was just generating
alphabetic patterns across blocks and that got 130 gb on a tape. Unfortunately
in the real world data data does not come like that.

John




"Long, Matt" <Matt.Long AT MARRIOTT DOT COM> on 14/02/2000 14:45:07

Please respond to "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>

To:   ADSM-L AT VM.MARIST DOT EDU
cc:    (bcc: John Naylor/HAV/SSE)
Subject:  Re: ADSM 9840 & Compression



John,

        We are also seeing some bizzare compression rates with the 9840.
Some of our tapes are reporting over 80Gig of data. I don't know if this is
a bug or what. We are using ADSM attached to an AIX RS6000.  Thanks

Matt Long
Systems Administration
Marriott International