Red Hat has filed a brief with the US Supreme Court emphasising practical problems with software patents.

The brief was filed in the Bilski case, which involved the standard for patenting a process. A US Court of Appeals restricted patenting of business methods. In the brief, Red Hat asks the Supreme Court to adopt the lower court's "machine-or-transformation" test and exclude software from patentability.

Red Hat argues that the patent system is supposed to foster innovation, but in software it does the opposite, slowing and discouraging innovation. Software products may involve thousands of patentable components, leaving developers to risk defending costly patent infringement claims.

The federal circuit court has set forth a test in which a business process must be tied to a particular machine or apparatus or "transform a particular article into a different state or thing" before it can be patented, Red Hat said.

The company argues that this standard is consistent with Supreme Court case law and should be applied to exclude algorithms, including computer software, from being patented. The scope of patentable subject matter is critical to the future of software development, including open source software, said Red Hat. The Supreme Court's decision in the case could clarify the law and lessen risks that innovation will be hindered by patents, according to the company.

"We think software is within the framework of things that are too abstract to be patented," said Rob Tiller, Red Hat vice president and assistant general counsel for intellectual property. Software is basically an expression of algorithms and mathematical in a sense, and the Supreme Court has ruled that mathematical algorithms cannot be patented, he said.

Oral arguments in the case are scheduled for 9 November, Red Hat said. Red Hat's brief can be accessed here.