Microsoft will take a swing at VMware at WinHEC this week by announcing plans to accelerate the delivery of its planned virtualization hypervisor, code-named Viridian, and will debut its virtualization management platform, code-named Carmine.

The plan is to try to get Viridian in private beta into a limited number of partners' hands sometime in the fourth quarter of 2006 and make it available as an add-on service for Windows Longhorn Server in the next two years, sources said. It is currently slated for the R2 release of the Windows server expected in 2009 or 2010.

That's not all. According to sources, Microsoft is in negotiations to buy application virtualization software ISV Softricity, Boston. The deal was not yet completed as of late last week, but talks are serious, sources said.

Also at WinHEC, Microsoft is expected to discuss a feature for Windows Vista developed with Softricity and informally dubbed Virtual DLL.

The Virtual DLL feature developed by the two companies will enable users to virtualize application registries and "end DLL hell once and for all," several sources said.

"I know Microsoft has been talking to Softricity and working with engineers at Softricity," said one source familiar with the joint development work on Virtual DLL. "It allows you to have a virtual registry instead of a single registry so you have can have multiple DLLs sitting on the registry. The benefit for us is it removes application conflicts. With this, you can run Office 97 and Office 2003 on the same machine," the source said.

The flurry of activity in Microsoft's virtualization unit comes as market leader VMware prepares to announce availability of its next-generation ESX Server 3 and VirtualCenter 2 platform during the first week of June.

Sources said corporate customers are pressuring Microsoft to speed up development of its VMware-style hypervisor and management platformor they will adopt VMwarebecause they don't want to wait for the immediate ROI benefits of virtualization.

Microsoft declined to comment on this story.