It was just over a year ago that Microsoft dropped a bombshell of a claim: users of Linux and open source software were unwittingly violating as many as 235 Microsoft software patents.

"This is not a case of some accidental, unknowing infringement," Horacio Gutierrez, Microsoft's vice president of intellectual property and licensing, told Fortune magazine at the time. "There is an overwhelming number of patents being infringed."

Since then, critics say Microsoft has played the "good cop, bad cop" routine with the open source camp.

For example, promising not to sue customers of eight vendors that had signed cross-licensing deals with Microsoft for potential open source-related violations? Good cop. But continuing to refuse to publicly reveal what those alleged patent violations are? Bad cop.

Here's another: Announcing in March that open source developers will now be able to use hundreds of Microsoft software protocols without a license for noncommercial use? Good cop. CEO Steve Ballmer telling customers of licensing holdout Red Hat last October that they "have an obligation to compensate" Microsoft for IP violations? Bad, bad cop.

Gutierrez, interviewed late last week, says Microsoft's hot-and-cold engagement with the open source community is neither "intentional" nor "inherently contradictory."

"We spend $7 billion a year on research, development and cranking out innovations," he said. "We need to protect our innovations against people who infringe upon them."

But legal eagles in the open source camp argue that Microsoft's moves, even its ostensibly positive ones, have done little to bolster its patent claim.

"Claiming you have IP that folks are infringing isn't the same thing as proving it," wrote Pamela Jones, author of the open source legal blog Groklaw.net, in an e-mail. "I think they [Microsoft] are in a weaker position *because* they did the [cross-licensing] deals. It makes them look needy, like they can't make it any more without Linux."

"The [legal] threat [to open source] is no greater" today than a year ago, wrote Mark Radcliffe, a lawyer with DLA Piper's Silicon Valley office and the general counsel of the Open Source Initiative, which oversees the approval of open source software licenses, in an e-mail.

Take Redmond's attempts to persuade vendors to sign cross-licensing deals that include protection from potential open source patent lawsuits by Microsoft.

Besides Novell and Fuji-Xerox, which both had signed deals before PatentGate, other cross-licensees include Asian consumer electronics makers Samsung Electronics, Kyocera-Mita, and LG Electronics, and a trio of smaller Linux makers including Xandros and its Scalix subsidiary, TurboLinux, and Linspire.

The number of patent signees remains at 8.

In an interview last week, Gutierrez said that cross-licensing is vital because "customers don't want to buy an IP problem."

Moreover, it sets the necessary groundwork so that Microsoft and its partners can comfortably work together to make their respective products interoperate.