Microsoft would like to take royalties from Linux and other free, open-source software, according to the company. The Windows developer alleges that the operating system and related programs infringe on 235 design patents -- 107 of which are trampled on by Linux and its interface alone. Microsoft's licensing chief Horatio Gutierrez claims that the sheer volume isn't coincidental.

"This is not a case of some accidental, unknowing infringement," he says. "There is an overwhelming number of patents being infringed."

While the company has not targeted any specific firms due to the inherently distributed nature of most free open-source code, the company is reportedly considering asking for royalties from major Linux vendors which it could argue were encouraging use of the infringing software.

Microsoft has already exerted pressure on Linux specifically in the past, having signed a deal with Novell late last year that shielded the latter against any patent disputes in return for royalties. Dell followed suit last week, which may guard its Ubuntu Linux systems against similar threats.

Still, the Redmond-based firm's path may not be as unimpeded as it would hope, says Fortune. Software is math and therefore can't be patented, according to the Free Software Foundation's counsel Eben Moglen. Microsoft also faces the possibility of very large companies such as Philips and Sony retaliating with countersuits, as several firms have formed the Open Invention Network specifically to defend their use of programs like Linux. This creates a "tinderbox" situation where Microsoft is hesitant to sue for fear of retaliation, says Moglen.

Microsoft's CEO Steve Ballmer is less concerned than his licensing chief, declining to say whether or not he would demand lawsuits from companies that refuse to participate in its Linux royalty licensing system.