Enterprises are widely adopting open source technologies in order to give their customers access to bleeding-edge features and functionalities. How do you see the proprietary Hyper-V competing with open source Xen-based hypervisors from Citrix and Sun?

O'Rourke: IDC, Gartner, and others also indicate that enterprises are widely adopting proprietary software. We know our customers drive innovation using a mix of open source and proprietary software. As it relates to Windows Server 2008 Hyper-V, we expect IT pros, admins, developers, and others who are familiar and know Windows will be excited by Hyper-V. It's the Windows they know. And for those not familiar with Windows, they know that we have done extensive work with Citrix (initially XenSource) and Novell to ensure hypervisor compatibility and OS support on each others' hypervisors.

Customers running multiple hypervisors (and many will) will benefit from this work, as well as our open interfaces, standards work, and the fact that Microsoft's Virtual Hard Drive image format and Hypercall APIs are available under Open Specification Promise.

Shields: Citrix's Xen-based virtualization solution isn't really open source anymore. Yes, the core of it is. But people will be buying Citrix's proprietary and for-cost management utilities to run it. S, the play there is muted. Also, as far as I know, Xen remains a heavy Linux-based solution, something that won't play well in Microsoft-centric shops. Hence, Microsoft's Windows focus for Hyper-V. This is a product that is friendly to the Windows admin who doesn't know and doesn't want to learn Xen's heavy Linux requirements.

Hyper-V only addresses Windows-based servers despite the fact that most datacenters are incredibly heterogeneous and require support for more than just Windows workloads. Aren't you underestimating the complexity and diversity of your customers' datacenters?

O'Rourke: No we're not. Our customers make sure we know their datacenter needs and provide us input on how we can help. So far they're telling us Windows Server 2008 has been a big help. As for Windows Server 2008 Hyper-V, it allows customers to consolidate applications running Novell SLES 10. As for Red Hat, Microsoft and Red Hat both realize the importance of virtualization and interoperability needs of our joint customers, and we are actively discussing how to support Red Hat Enterprise Linux on Windows Server 2008 Hyper-V.

Shields: Hyper-V doesn't address only Windows-based VMs. It supports SLES as well. Microsoft's support for additional Linux OSes is muted because Microsoft hasn't seen the demand for it. They're demanding a rock-stable virtualization platform that supports some of their workloads. Why do a poor job being all things to everyone when you can do a great job fixing a specific market segment?

Going along this road further, SCVMM [System Center Virtual Machine Manager] includes support for managing the Xens and ESXs of the world. Let those virtualization platforms do the oddball OS virtualizing, and let Microsoft handle its own product stable.