Mike Neil, Microsoft's general manager of virtualisation, is on the big stage with a hot technology. The lights are on him as he prepares for next year's delivery of Windows Server Virtualisation, which first was a feature and now is an add-on to Windows Server 2008.

Neil, who joined Microsoft four years ago as part of the Connectix acquisition, recently talked with Network World senior editor John Fontana about critics, competition, licensing and feature delays.

Q: The prevailing belief among observers is that Microsoft is way behind VMware. What do you say to the WSV-bashers? A: At a high level, I disagree. Server virtualisation is still a developing market and technology. Since, to a great degree, the utilisation of virtualisation has been in relatively confined areas, typically in large enterprises or infrastructure products like [VMware's] ESX Server, Microsoft will be able to have a much broader approach and make virtualisation available to a wider swath of the industry.

Q: Are you on track for a mid-2008 release of WSV? A lot of people are casting doubts after your spring roadmap adjustments. A: We made the adjustments - the deferral of some of the features - so we could maintain our schedule and provide the technology with high quality on the timeline that we articulated: Windows Server 2008 plus 180 days. [The server is set to ship 27 February, 2008.]

Q: Will the delayed WSV features be delivered in some fashion before the next release, which could be as many as four years away, given the server operating-system release cycle? A: Windows Server Virtualisation is coming out off the [server] cycle, and while we do plan to follow up with the deferred features in subsequent releases of the [operating system], we have not talked about specific timing. We are hoping to sync up with the cycle.

Q: Sync with the Windows Server R2 release, slated for late 2009, or the next major server release, in 2011? A: Our goal is to follow up with those features as quickly as possible.

Q: Critics say the delay of the Live Migration feature, which would provide the ability to migrate while virtual machines are running, is a big setback for Microsoft as it tries competing against VMware. What's your take? A: I dispute it to some degree. From a competitive standpoint, it is a sexy feature and sounds really exciting. But, of the Microsoft customers using VMware or other virtualisation technology, few are actually utilising that type of functionality. It is a relatively sophisticated piece of technology to set up. The capabilities we do have and are shipping - our ability to cluster virtual machines and the ability to migrate quickly - will meet most customers' needs.

Q: Some predict the demise of Virtual Server and Virtual PC, your current server and desktop virtualisation products. Are those two in active development or static mode, especially in the light of the delays in delivering updates to Virtual Server? A: We released Virtual PC 2007, which has Vista support as both a host and guest, in February. We released Virtual Server [2005] R2 SP1 in June. We continue to develop on both, and we are actually growing the teams that are developing those products.

Q: Competitors have questioned Microsoft's licensing as it relates to moving virtual machines among different computers. What constraints will users face on how and when they can move virtual machines? A: We made changes to Windows Server licensing specifically to address moving virtual machines. With our instance-based licensing, we have moved from the installation of the operating systems being the defining event when a license is consumed, to when you instantiate an image of an operating system. And so from a license perspective, we want the customer to understand the licensing is in the utilisation when they run our software. They can move those instances between any two licensed devices as much as they want.

The criticism some folks have had is they don't feel there should be two licences involved in that case. In reality, customers say they have licensed Windows for their systems and they just want the ability to move around the images and the instances. Customers who want the ultimate in flexibility can use our datacentre licensing, which allows them to run an unlimited number of virtual machines.

Q: Application virtualisation is part of your overall virtualisation strategy, so why do you offer it only to customers with Software Assurance contracts? A: The basic business model we are using for application-virtualisation technology is to provide it as part of the value-add you get with Software Assurance. It provides those customers - who are typically our largest customers and typically deploying that kind of technology - with a way to gain that value over time as opposed to licensing it perpetually for each one of their machines.

Q: What role does security play in this virtualisation environment? A: That is an interesting problem. Today, with the architectures we have, the hypervisor level of the software is being targeted by more and more of the malicious-software industry. You can see that by looking at the security updates that VMware has had. Microsoft has shown we have been responsive to the security threats out there and put in place the processes to make our products secure and react to any security issues.