Microsoft to Make Viridian Hypercall API Widely Available

By Peter Galli  |  Posted 2007-10-24 Print this article Print

The Windows Management Interface to the virtualization technology will also be accessible to partners.

Microsoft will make the hypercall API in Windows Server virtualization available under its Open Specification Promise when the product is released to manufacturing late next year. This means that the API can be used without licensing fees and with Microsofts guarantee that it will not sue for violation of its patented intellectual property.
However, for customers who want early access to the interface, Microsoft has posted an updated draft of the hypercall API to its Web site.
The move will be announced Oct. 24 at the Interop New York 2007 conference and expo, where Microsoft is showcasing some of the interoperability resulting from its collaboration with the companies that are part of the Microsoft-sponsored Interoperability Vendor Alliance. "The OSP [Open Specification Promise] is a simple, clear way to reassure a broad audience of developers and customers that any Microsoft patents needed to implement all or part of the specification can be used for free, easily, now and forever, to the extent that the specification is being implemented," Patrick ORourke, group product manager for Microsofts server and tools business, told eWEEK. To read more about Microsofts move to make its Virtual Hard Disk image format specification available to users, click here. The Windows Management Interface to Viridian—the code name for Windows Server virtualization—is based on the industry standard in development in the DMTF (Distributed Management Task Force), and will also be made accessible to partners, he said. The hypercall API enables partners to develop solutions with Windows Server virtualization, which they can use to integrate or extend their software with Windows Server 2008 and Windows Server virtualization. "For example, this is the API to which Novell and XenSource are developing against for interoperability with Viridian," ORourke said. Microsoft, of Redmond, Wash., first distributed the hypercall API documentation to attendees of its 2006 Windows Hardware Engineering Conference. The company has gotten feedback on the hypercall APIs from, among others, the Xen and Linux communities through its relationships with XenSource and Novell, he said. Read more here about why Microsoft cut core features from Viridian. VMware and the major chip and OEM vendors have also had access to drafts of the hypercall API specification, ORourke said. "This move follows on our earlier decisions to extend the OSP to virtualization and is another step in our efforts to promote technical development in the virtualization space in the broader community by contributing our own technology to the space," Tom Robertson, Microsofts general manager for interoperability and standards, told eWEEK. When Microsoft and XenSource joined forces in July to facilitate server virtualization, Frank Artale, vice president of business development at XenSource, said a key piece of the work would be to provide an adapter between the Xen hypercall API and the Microsoft Viridian hypercall API. XenSource CTO Simon Crosby said the company is committed to delivering value-added virtualization solutions for the Windows platform and that interoperability with Viridian was an important element. Read more here about the alliance between Microsoft and XenSource. "This is made possible by Microsofts licensing of key technologies such as its VHD image format and the Windows Server Virtualization hypercall API, which will allow us to ensure that Xen-enabled Linux guests will be compatible with Windows Server virtualization when it is delivered as a component of Windows Server 2008," he said. Check out eWEEK.coms for Microsoft and Windows news, views and analysis.
Peter Galli has been a financial/technology reporter for 12 years at leading publications in South Africa, the UK and the US. He has been Investment Editor of South Africa's Business Day Newspaper, the sister publication of the Financial Times of London.

He was also Group Financial Communications Manager for First National Bank, the second largest banking group in South Africa before moving on to become Executive News Editor of Business Report, the largest daily financial newspaper in South Africa, owned by the global Independent Newspapers group.

He was responsible for a national reporting team of 20 based in four bureaus. He also edited and contributed to its weekly technology page, and launched a financial and technology radio service supplying daily news bulletins to the national broadcaster, the South African Broadcasting Corporation, which were then distributed to some 50 radio stations across the country.

He was then transferred to San Francisco as Business Report's U.S. Correspondent to cover Silicon Valley, trade and finance between the US, Europe and emerging markets like South Africa. After serving that role for more than two years, he joined eWeek as a Senior Editor, covering software platforms in August 2000.

He has comprehensively covered Microsoft and its Windows and .Net platforms, as well as the many legal challenges it has faced. He has also focused on Sun Microsystems and its Solaris operating environment, Java and Unix offerings. He covers developments in the open source community, particularly around the Linux kernel and the effects it will have on the enterprise.

He has written extensively about new products for the Linux and Unix platforms, the development of open standards and critically looked at the potential Linux has to offer an alternative operating system and platform to Windows, .Net and Unix-based solutions like Solaris.

His interviews with senior industry executives include Microsoft CEO Steve Ballmer, Linus Torvalds, the original developer of the Linux operating system, Sun CEO Scot McNealy, and Bill Zeitler, a senior vice president at IBM.

For numerous examples of his writing you can search under his name at the eWEEK Website at


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