A total of 283 registered software patents, including 27 held by Microsoft, could conceivably be used as the basis of patent lawsuits against the Linux kernel, according to a study of U.S. software patents released today.

The study was funded by Open Source Risk Management (OSRM), a company that provides insurance against lawsuits related to the use of open source products, and conducted by patent attorney Dan Ravicher, executive director of the Public Patent Foundation and senior counsel to the Free Software Foundation.

"There is a nontrivial risk of patents being asserted against Linux," said Ravicher, who added that his findings should not come as a great surprise given the broad scope of the Linux project. "The conclusion we came to is not that Linux is doomed and that this is horrible," he said. "It's very similar to the result you would get if you investigated any other software program that's as successful as Linux."

Though a patent lawsuit relating to some piece of open source software is "inevitable," it is unlikely that Microsoft will be the company to launch such a suit, according to Jeffrey Norman, a software lawyer at Kirkland & Ellis in Chicago. "I don't know if it's going to be Microsoft," he said. "There are some PR issues for Microsoft."

Because of their open nature, projects like the Linux kernel are more vulnerable than proprietary software to patent claims, said Norman. "It's much easier if you have a software patent to go through an open source product and verify that your patent is there," he said.

But a larger problem is that in the relatively young craft of software development it is easy to come up with techniques that, while novel, should probably not be patentable, said Norman, who cited Amazon's patent for one-click purchasing as an example of such a technique. "The novelty is not novelty with a capital 'N.' You're not inventing the internal combustion engine," he said.

Ravicher's organization, the Public Patent Foundation, which claims that half of the patents issued by the U.S. Patent Office contain no innovation, is lobbying for reform of patent laws, but Ravicher says that efforts like Grokline.net, which is an OSRM-sponsored effort to catalog the roots of the Unix operating system, could also protect open-source software from patent suits.

The IDG News Service is a Network World affiliate.