"Microsoft’s latest release of their server product,
Windows Server 2008, promised something big: a built-in hypervisor.
Yet, this did not ship with the product. In order to finally get
out the door, Windows Server 2008 was released with only a beta
version of this functionality. The release to manufacturing has
only now not long taken place. There will be licensing costs if you
want to use it, however. By contrast, Linux has had hypervisor
technologies available already – and it doesn’t need it
for best results, anyway."