Windows Azure, Microsoft's cloud computing environment, is the foundation of the Azure Services Platform for developing applications extending from the cloud to PCs, datacenters, phones, and the Web unveiled. During the PDC keynote, Microsoft Chief Architect Ray Ozzie mentioned that the company's cloud computing technology was built on top of a hypervisor.

However, Amitabh Srivistava, Microsoft corporate vice president, Windows Azure platform, told in an interview that the hypervisor found in Azure is not Microsoft's Hyper-V virtualization technology:

"No, we have our own hypervisor, which we have designed specifically for the design point. We just call it Windows Azure hypervisor, but a lot of the advancements we are making are moving into Hyper-V, [so] the same thing will be available to the on-premises customer. The virtualization support that you get in hardware like NPT and EPT, the nested page tables that are there. We are taking a lot of advantage of that, so that's what [Microsoft engineer] Dave Cutler has done in really optimizing the thing out, so the overhead of the hypervisor is extremely low. And when the hypervisor overhead is low, then we can get maximum utilization by dividing the machine."