Microsoft opens Virtual PC and VHD specs for rivals

Microsoft has made freely available one of its key specifications used to manipulate virtual servers and applications, which is being seen as an attempt to up the interest in its virtualization softwares.

Microsoft said on Tuesday it would allow anyone to use its specifications for "virtual" drives, which enable one computer to run several operating systems at the same time, with the promise never to sue for infringement of its legal rights.

The Microsoft virtualization software -- Microsoft Virtual PC -- has been available for more than two years, but as computers become more powerful the use of virtualisation is expected to mushroom, the company said at a news conference.

Such virtual software is also made by VMWare, a unit of EMC Corp., which helped pioneer the market.

However, those wishing to use Windows Vista within such virtual machine technologies will not be able to do so with the standard Home Basic and Home Premium packages. Only Vista Business and Ultimate Editions will work with software such as Virtual PC, VMware and Parallels.

The company said the license was "an irrevocable promise from Microsoft to every individual and organisation in the world to make use of this patented technology for free, now and forever when implementing specified open standards".

Earlier this year, Microsoft said it would team up with Linux supplier XenSource to supply the virtual specifications to permit Windows and Linux to run on the same machines.

Virtualization has become a popular technology in IT departments because it allows companies to save on hardware costs. A single machine can run several operating systems, and VHD allows the entire operating system and application stack to be contained in a single file.

The move by Microsoft has been generally welcomed by both open source advocates and competing vendors.

More than 60 companies have already adopted VHD, which include names like Diskeeper, Fujitsu Siemens and XenSource. The format allows for migration across Microsoft Virtual Server, Virtual PC, and Windows Server virtualization with Windows Server "Longhorn," the company said.

This decision by Microsoft is partially forced as well as the question of making software open to others has been at issue in Brussels, where the European Commission has ordered Microsoft to share protocols with rival makers of servers.