A virtualization deal struck Monday between Microsoft and Red Hat shows the growing need for vendors to ensure customers can get cross-platform support for applications running in virtualized environments.

Under the terms of the deal, outlined in blog posts by Microsoft Senior Open Source Community Manager Peter Galli and Microsoft Virtualization General Manager Mike Neil, both companies will validate and offer customer support for each other's OSes on their virtualization technologies.

Stephen O'Grady, an analyst with open-source research firm RedMonk, said the deal underscores how even competitors have to cross party lines to support virtualization, which is becoming an integral part of data centers that, more often than not, include both Windows- and Linux-based servers.

No doubt Red Hat wanted to be sure to clarify that its deal with Microsoft is not the same as the one Microsoft struck with Linux distributor Novell two years ago, which did include exchange of IP and cash. At the time Red Hat executives said they were not interested in striking such a deal. In addition to ensuring interoperability between Novell SUSE Linux and Windows, the Novell deal also indemnified users of Novell's Linux against any claims of patent infringement for any Microsoft patents SUSE Linux might include.

IP is a particularly thorny issue between Microsoft and Red Hat, exacerbated not only by the Novell deal but also by claims made by Microsoft CEO Steve Ballmer in May 2007 that Linux violates more than 235 patents Microsoft holds.

In response, Red Hat said its customers are protected by any patent claims by its Open Source Assurance Program, and many Linux proponents called Microsoft's claims an attempt to spread fear, uncertainty and doubt (FUD) among customers who purchase open-source software in order to promote its own proprietary software.

O'Grady suggested it was probably Red Hat that lobbied hard against including IP-sharing in the deal to maintain its stance against the Novell deal and Microsoft's patent-infringement claims.

"This is a different deal than Novell signed," he said. "It's far less controversial."

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