Microsoft gives Linux a virtual hug

The software maker is announcing a partnership Monday night that will make sure its next virtualization technology can run versions of Linux that have been adapted for a different, open-source virtualization foundation called Xen. It is linking up with commercial software maker XenSource to offer joint development and support for the two technologies, which take a similar approach.

"What Microsoft and XenSource are committing to, effectively, is building a bridge" between the two tools, said Jeff Price, a senior director in Microsoft's Windows Server group.

Both are based on the notion of a hypervisor--that is, low-level software that lets multiple operating systems share the same hardware. An operating system must be adapted for Xen to run best on the hypervisor. However, features in new processors from Intel and Advanced Micro Devices let unmodified operating systems, such as Windows, run on Xen. The Microsoft-XenSource collaboration is designed to return the compliment, letting Linux adapted for Xen also run on Microsoft's hypervisor.

Xen is available now, and was added this week to Novell's Suse Linux Enterprise Server 10. Microsoft's hypervisor technology (code-named Viridian) is still more than a year away. It is slated to be shipped within six months of Longhorn Server, the operating system update set for delivery at the end of 2007. A beta, or test, version of Viridian is scheduled to be ready by the close of 2006, Microsoft said.

When Microsoft said Viridian wouldn't ship at the outset with Longhorn Server, some expected that meant it would arrive with Service Pack 1, due at least 18 months later, in 2009. But Microsoft indicated in April it wanted to release Viridian sooner.

Microsoft has been working in several areas to improve how well Windows and Linux interoperate, a reflection of the company's slow realization that open-source software is not going away. On the virtualization front, it already has added Linux support in its Virtual Server product.

"Customers have been very positive about that," Price said. "Customers want to have assurances that they can run Linux in a supportive and high-performance manner."

The arrangement comes as virtualization, or using one computer to act as many, takes center stage for the software industry. There is increasing interest in having a single PC or server run many different operating systems, rather than one operating system. The shift is bringing profound technological and business model challenges to software companies.

Under the new deal, Microsoft will work with XenSource to provide support for customers using Xen with Windows Server's hypervisor. If there are problems, they can call Microsoft.

"If it is a problem with the Windows hypervisor, we'll fix it," Price said. If it's a Linux or Xen issue, he said, Microsoft will "make sure they get the right Linux support."

For XenSource, the deal opens up the option of creating software that works with both Windows and Linux hypervisors.

"It really is about providing a much larger market for the products and services that we want to build, (products) that have become possible via the broad adoption of virtualization," said Frank Artale, a vice president at XenSource.

CNET News.com's Stephen Shankland contributed to this report.