For Windows every machine (compute node) would need a individual license.
I have 200 GRID machines, 400 SMPs of linux clusters, plus a 20ish linux
machines. (each with hundreds of users/applications). And the software
is FREE on most of these (no license required). So for EVERY linux cluster
that does not have SuSE SLES or RedHat ES/AS, it is not counted, since
there are no dollars required.

It should be the number of SMPs installed (so clusters count on a per-node
basis) and not dollars wasted by companies. I grant sometimes it is needed,
but the majority is just lack of knowledge in companies. (like purchasing
windows to run filesharing versus samba, or email or MS SQL server/MS Access
instead of Oracle/MySql/Postgres).

And really a LARGE SMP should count for more computing power and productivity
than a toy PC that was called a 'server'. IBM Pseries or HP etc..

Mark