When the Supreme Court heard the Bilski case earlier this year, it ruled that the specific business method patent at issue in the case was invalid and contended that the patentability of intangible methods should be reduced but not eliminated. The court declined to provide clarity on the scope of software patentability, however, which leaves a lot of important questions unanswered.

The United States Patent and Trademark Office (USPTO) has been left with the difficult responsibility of interpreting the ambiguous Bilski ruling so that it can set new standards. The USPTO has invited the public to submit comments to help it establish new guidance on patentability in the post-Bilski world. Because the issue of software patentability has profound relevance for the open source software ecosystem, Linux distributor Red Hat has submitted responses to the request for public comments.

Red Hat's submission was authored by Rob Tiller, the company's vice president and assistant general counsel. He argues that a growing number of vague patents on software methods have made it impossible to guess whether a new product will face the risk of litigation. His statement contends that the resulting landscape of uncertainty discourages innovation in the software industry.

"Introducing any innovative software product entails a risk of a lawsuit based on a vague patent. Such lawsuits often cost millions of dollars to defend, along with the risk of actual damages, treble damages, and injunctions," he wrote. "The problem of vagueness is so endemic in software patents that it warrants action at the threshold level of subject matter eligibility."

Tiller points out that the ruling in Bilski reaffirmed the long-standing rule that a mathematical formula is not patentable. On that basis, he argues that the USPTO should conclude that software methods are not patentable material. The validity of this interpretation rests on the question of whether software code that implements an algorithm is simply a representation of the algorithm or a patent-worthy practical application of the algorithm.

"As the Supreme Court found in Diehr and reiterated in Bilski, an application of a mathematical formula (as opposed to the formula by itself) may be entitled to patent protection. This does not mean, however, that merely storing or running software on a general purpose computer justifies granting a patent on an otherwise unpatentable algorithm," Red Hat's submission reads.

The submission follows an effort by the Free Software Foundation (FSF) to raise awareness in the open source software development community about the USPTO's guidance request. The FSF is encouraging concerned developers to submit statements to the USPTO in support of ending software patentability.