For Microsoft, the idea is to help businesses run both Linux and Windows . If all goes according to plan -- and experts are saying that is a big if -- the two companies will jointly develop technologies ranging from virtualization and Web services to document formats and file converters.

Additionally, under a patent cooperation agreement, each company will provide patent protection for the other's customers. The wide-ranging pact also includes combining marketing and sales efforts, and will run through 2012.

Historic Agreement

Microsoft concedes that a growing number of businesses are now running multiple software platforms, and need the assurance of interoperability going forward. At the same time, Novell recognizes that its enterprise customers want patent protection from Microsoft in connection with their use of SuSE Linux.

"It's a historic agreement, and a change in direction by Microsoft, but the proof is in the pudding," said IDC analyst Stephen Elliot. "Microsoft needs to support the open-source platform, but the key will be how extensive that support is."

Elliot suggested that the partnership is a smart move for both parties in that it will provide business customers with better I.T. security, data -systems management, and improved virtualization. "But for users of Linux and Windows, Microsoft has to demonstrate a commitment to interoperability," he added.

Forrester Research analyst Mike Gilpin, citing Microsoft's recent collaboration with PHP specialist Zend, noted that Redmond has recently shown a greater willingness to enable the coexistence of Windows and Linux.

"More businesses are now running both Linux and Windows, with open-source software playing a key role in all layers of the stack, so it's no longer an all-or-nothing proposition for Microsoft," Gilpin said. "And, of course, this is another opportunity for them to sell more software through a marketing arrangement."

Concession by Microsoft?

The two companies will create a joint research lab for designing and testing new software in three primary areas: virtualization, Web services, and document formats

The fruits of the collaboration should mean that customers will be able to run virtualized Linux on Windows or virtualized Windows on Linux.

Protection against patent infringement claims is provided so that Microsoft agrees not to assert claims against customers who have purchased SuSE Linux Enterprise Server and Novell will protect those who have a licensed version of Windows or other Microsoft software.

Still, IDC's Elliot said there is some concern about possible contamination of the Linux platform with the cross-licensing agreement.

"There are a lot of issues to be resolved, such as the level of software management support, the extent of shared software development resources, and the possible impact on virtualization," he said.