The United States Court of Appeals for the Federal Circuit handed Open Source developers — and a model train enthusiast — a hard-fought victory yesterday, as it laid down the law — quite literally — regarding copyright infringement claims that result from the violation of an Open Source license.

Robert Jacobsen, manager of the Java Model Railroad Interface, an Open Source project organized around model trains, sued Kamind Associates and Matthew Katzer in 2006 for allegedly failing to adhere to the license terms applied to the JMRI's DecoderPro software, which is distributed as an Open Source project through SourceForge. According to Jacobsen/JMRI, Katzer and Kamind Associates utilized DecoderPro code in their application, Decoder Commander, without complying with various license terms, including failing to provide attribution and maintaining copyright notices, along with neglecting to identify the original source and include a changelog for their adaptation of the code.

The defendants argued back that because the code is available free of charge, that Jacobsen/JMRI shouldn't be entitled to monetary damages for infringement of their work — essentially, arguing that because JMRI does not profit from its work, there is no financial harm to them, and thus no basis for renumeration. Jacobsen/JMRI, of course, disagreed, asserting that the license terms were clearly stated, and that failure to comply with those terms is an infringement of the copyright. The District Court, where the action began, ruled partially for each side, finding that Katzer and Kamind Associates had breached the license, but was not liable for copyright infringement, under the doctrine that once one grants a non-exclusive license to use a particular material, they have exchanged the right to sue for copyright infringement for a breach of contract action.

The appeals court disagreed — and this is the important part for Open Source projects — finding that the requirements to provide attribution and to disclose alterations to the software are intended to further the project by drawing users back to the original project and making its existence known, and that this qualifies as a "significant economic goal" which the court is bound to protect. For now, though, the victory is for the most part in principle — the appeals court has set down the standard, but it is now up to the District Court to rehear the matter and decide what, if any, violation occurred.

As always, the vigilant forces at Groklaw have put together an extensive discussion of the decision, along with full text of the Court of Appeals' decision.