But they are not yet prepared to say exactly when "sooner" might be, especially in light of the recently announced slips in the release of Windows Vista and Office 2007.
Viridian is technology that will run beneath the operating system and manage resources for multiple virtual machines.
"While Viridian will be delivered after Longhorn Server ships, Longhorn will be virtualization-ready," Mike Neil, product unit manager for Microsofts virtualization technologies, told eWEEK at the annual LinuxWorld Conference here.
Asked whether Microsoft is feeling pressure to speed up the delivery of Viridian given that Red Hat Linux and Novells SUSE Linux both planned to bake the Xen hypervisor technology into their server products slated to ship later this year, Neil said Microsoft is actually happy that the Linux vendors were embracing hypervisor technology similar to Viridian.
He also pointed out that Microsoft Research in the United Kingdom contributed to the development of the Xen hypervisor technology, which was initially a project at the University Of Cambridges Computer Laboratory.
"The Xen and Viridian hypervisor architectures are actually more similar than they are different, and the inclusion of this technology into the Linux distributions broadens the market and ecosystem around this technology, which is good for all of us," he said.
But Neil did acknowledge that the fact that VMware has made its VMware Server product available for free and both Red Hat and Novells SUSE are baking the Xen virtualization technology into their server products had put pressure on Microsoft to also make its virtualization software available for free.
"Microsoft listens and responds to what our customers tell us, and customers were telling us they wanted this technology at no cost," he said.
Margaret Lewis, director of commercial solutions at Advanced Micro Devices, told eWEEK in an interview that the management of these virtualized environments will soon become the next big topic of discussion.
"For many customers, their first virtualization play involves creating virtual machines. But, once they know how to do that, it quickly becomes evident that you have to learn how to manage them, and I think we are going to see a shift away from all the talk about the hypervisor technology toward how best to manage this environment and what the tools are that help them with this," she said.
She also touched on a sensitive fact: that virtual machines are not necessarily free. "The software community is going through the same dilemma that AMD went through last year with multicore environments and how to price these," she said.
Microsofts Neil also reiterated that the current plan is for the license for the Datacenter Edition of Windows Server "Longhorn," when it ships next year, to give users the right to run an unlimited number of virtual instances on one physical server, while Windows Server "Longhorn" Enterprise Edition will be licensed to allow four virtual instances. But that could change, he said.
Currently, customers running Windows Server 2003 R2 Enterprise Edition can run as many as four virtual instances on one physical server at no additional cost. If they want to run more instances of Windows Server, they have to buy another Windows Server 2003 R2 Enterprise license that gives them four additional virtual instances.