We are running 120 Oracle 10g servers and 160 SQL 2005 servers. The problem is we want to migrate to Server 2008 R2. The problem is Oracle 10g R1 won't run on the Server R2 so we have to step backa little for those. The result is a mixture of Windows 2008 R1 and R2 machines (as part of our migration) and the older Server 2003 R2 machines for our legacy applications that we can't do without.

The reality is that in large networks with alot of applications, having a single Server OS and service pack installation thoughout the enterprise simply isn't possible.