We have been using 3480 cartridges on a VM system for over a year now
with about 100 users (with *LOTS* more coming real soon now.)
I've recently gotten access to 3490s and have them working with VMTAPE,
too.

So I changed the NEXTPOOL parms of the 3480s to point to the 3490s and it
immediately started to move (what looked like) all the data to the
the 3490s.   I quickly cancelled that PROCESS because it was not what
I intended.   It did raise the question of what the HI & LOW parms mean
when you're talking about tape media.  (It means nothing when you have no
NEXTPOOL but when one exists then what??? (compared to DASD!)

And, with COLLOCATION ON, will it move *all* a users data to new 3490s when
its moving *any* of it from dasd to tape?

Someone suggested making the 3480s a READ/ONLY group but then I'm confused as
to whether to make the 3490s part of the same STGPOOL or a NEXTPOOL group?

      thanks for your help!

                .. joe.f.