How important are software patents? We know they're a threat to the freedom of developers to collaborate openly in communities, chilling the commercial use of shared ideas that fuels engagement with open source. We know that the software industry was established without the "incentive" of software patents. But the importance of the issue was spotlighted yesterday in a joint action by two leading open source organizations.

In a "friend of the court" (amicus curiae) briefing submitted to the U.S. Supreme Court, the Free Software Foundation and the Open Source Initiative joined the Software Freedom Law Center in calling for the verdict in the pivotal case CLS Bank vs. Alice Corporation to be affirmed. Written by lawyer and leading software freedom thinker Eben Moglen, the joint submission is the first united action by FSF and OSI since they joined in opposition to the transfer of Novell's patent portfolio by CPTN, a shady consortium of major software corporations opposed to open source.

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The brief asserts the basic arguments that processes are not patentable if they are implemented solely through computer software, and that the best test for whether a software-implemented invention is solely implemented through software is whether special apparatus or the transformation of matter have been presented as part of the claims (the "machine or transformation" test).

The brief goes on to assert that, in the long experience of both the OSI and the FSF, finding software-only inventions unpatentable will not imperil the pace of software innovation. That is fueled by free sharing and open publication, not by granting monopolies on ideas. The proof? The history of the free software movement and the worldwide adoption of open source software by industry -- notably by the largest holders of patents -- shows that patenting software has not contributed to the important software innovations of the last generation.

I endorse and welcome this joint position calling for firm clarity on software patents. (I was obviously party to the decision to take it, although I'm not writing on OSI's behalf here.) With 15 years of history behind us, there's far more that unites the FSF and the OSI than divides us. We've each played our part in the software freedom movement that has transformed computing. Now all of us in both communities need to unite to end the chilling threat of software patents to the freedom to innovate collaboratively in community.

This article, "Open Source Initiative, Free Software Foundation unite against software patents," was originally published at InfoWorld.com. Read more of the Open Sources blog and follow the latest developments in open source at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.