The open source community is split over Microsoft's claim that Linux infringes on its patents.

Last Tuesday, Paris-based Mandriva became the third Linux vendor within five days to say it isn't interested in signing a licencing deal with Microsoft to avoid possible infringement claims. A Mandriva blog posting to that effect by Mandriva CEO Francois Bancilhon followed similar declarations by officials at Red Hat and Canonical, which oversees Ubuntu Linux.

But earlier this month, Microsoft announced collaboration agreements with Xandros and Linspire that included patent covenants absolving them of any charges that their Linux distributions infringe on Microsoft intellectual property. Those deals were similar to the highly publicised agreement that Microsoft and Novell, the developer of SuSE Linux, signed last November..

Broward County Public School, uses Linux throughout its operations. CIO Vijay Sonty said that the split between Linux vendors over dealing with Microsoft "is not good for open source" and could give Microsoft an advantage in pressing its patent claims.

Sonty added that he thinks Microsoft "is lining up partners to go against" Red Hat and Ubuntu, which he sees as the company's biggest threats in the Linux camp. "The battle is just beginning," he wrote. "We don't know what is underneath the iceberg yet."

But Colt Jackson, a systems engineer and AIX technical expert at US health insurer CareFirst said that there are two sides to the Microsoft vs. Linux story.

"On one hand, it's a sexy story to portray this as a bit of a David vs. Goliath, or a shakedown," Jackson wrote. "On the other hand, if a company does not defend its patents, it will effectively lose control of them."

CareFirst is the parent company of CareFirst BlueCross BlueShield, which insures 3.1 million people in the US. Jackson, who runs some utility applications on top of SuSE Linux at CareFirst, said he isn't worried about any fallout from Microsoft's patent claims. But, he added, "if I were running a highly specialised application on a smaller [distribution], I might be concerned enough to have a contingency plan."

The intellectual property issue came to a head after Microsoft executives said that Linux and other open-source technologies infringe on 235 of its patents. The Microsoft officials said that they wanted to sign more deals like the one with Novell, which agreed to pay Microsoft a share of the revenue from sales of SUSE Linux.

Kevin Carmony, CEO of Linspire, said in that his company's agreement with Microsoft was designed to give users "improved interoperability, enhanced functionality and confidence."

But in his blog posting this week, Mandriva's Bancilhon contended that "absolutely no hard evidence" has been produced showing that Linux or other technologies infringe on any patents. "We don't believe it is necessary for us to get protection from Microsoft to do our job, or to pay protection money to anyone," he wrote.

On 16 June, Ubuntu Linux founder Mark Shuttleworth wrote in his personal blog that Ubuntu and Canonical officials had declined to discuss any deals with Microsoft "under the threat of unspecified patent infringements." That came one day after Linux market leader Red Hat reiterated that it wasn't interested in negotiating an agreement.

In a Microsoft statement, David Kaefer, the software vendor's general manager of intellectual property and licensing, said Microsoft "remains committed to working with all companies that have a shared interest in building the bridge between open-source and proprietary software."

"Microsoft has been buying up deals with little fish and companies that aren't quite making it financially," open-source advocate Bruce Perens said, referring to its agreements with Novell, Linspire and Xandros. But the vendors that have resisted its offers are taking the right stand, he said.

Jonathan Eunice, an analyst at Illuminata agreed that companies like Xandros and Linspire were "softer targets" for Micro­soft. Vendors like Red Hat and Canonical "don't need to take out the insurance policies" with Microsoft on its infringement claims, Eunice said.

But Laura DiDio, an analyst at Yankee Group Research in Boston, said it makes sense for some of the Linux vendors to sign deals with Microsoft that indemnify their customers against any claims.

"It can impact enterprise users if somebody decides to sue for patent infringement ... and they don't have any protection in place," DiDio said. "That is always a danger."