unique identifiers for cdrom drives

[Paul E Condon <pecondon@mesanetworks.net>]

My Squeeze installs on machines that have two cdrom drives seem to
boot sometimes with the upper drive as /media/cdrom0 and lower drive as
/media/cdrom2, and other times with the identities reversed. I'm sure
there must be a way to fix on one assignment and keep with it, but how?

There is nothing about cdrom drives in /etc/fstab. I suppose that 
something added there will fix the problem, but what?

I've googled and see reference to vol_id, but I don't have vol_id, and
can't find it, or even a man page.

TIA
-- 
Paul E Condon           
pecondon@mesanetworks.net