Anyway, at the moment we all know that Virtual Server is installed on top of Windows 2003. So your install footprint consumes ~2 Gb. Then your Virtual Machines, run on top Virtual Server. As per the diagram to your right. >
So lets fast forward a little bit. Windows 2008 CTP (aka Longhorn) has an install footprint of ~4.4 Gb. But we don’t need most of that install base to run Windows Virtualization.
So Windows 2008 can also be installed in a mode called ’Windows Server Core‘. Windows Core is a lean and mean install of Windows without any of the ’bells and whistles‘. Core has an install footprint of ~1.3 Gb. Then we need to add the hypervisor and Windows Virtualization role.
We will be watching this space with a lot of anticipation. Check out Dugie's blog. Also here.