The US Patent and Trademark Office has sealed a partnership with open source providers that it hopes will stop companies patenting prior inventions. 

Three proposals have been agreed so far, including a commitment from the open source community to improve the resources available for checking prior inventions.

Plans have also been accepted to develop a system to alert software writers when new patents are being researched, and to agree additional criteria for measuring the quality of software patents.

"For years now, we have been hearing concerns from the software community about the patent system," said Jon Dudas, US Under Secretary of Commerce for Intellectual Property.

"It is important that those in the open source community are joining the US Patent and Trademark Office to provide resources that are key to examining software-related applications."

Officials met with leading open source vendors last month to discuss the issue and will be holding an open meeting next month to finalise procedures for patent investigators.

Meanwhile IBM has retained its position of being awarded the most patents in 2005, with nearly double the number awarded to any other company or individual. The firm was awarded 2,941 patents last year, beating Canon which managed only 1,828.