The move will likely have little impact on IT managers, but it may affect vendors that create simple tools -- particularly ones that help with the migration to Xen and Microsoft -- and possibly patch management tools, said Tom Bittman, an analyst with Stamford, Conn.-based Gartner Inc.
"VMware has 95% to 98% market share, and the only way to break that is to try to promote another standard -- in this case, a compatible standard for Microsoft," said Bittman, as to why Microsoft is offering its virtualization technology at no cost.
Microsoft pledged to make its patented virtualization technology available to developers in September of this year. At the time, the company issued an Open Specification Promise for Web services specifications.
Virtual Hard Disk captures a virtual machine's operating system and application stack in a single file, allowing IT managers to pool their resources, according to Microsoft. Available since May 2005, VHD is now being used by more than 60 vendors.