Lineo, maker of the Linux-based embedded operating system Embedix, said on Monday it has licensed patented technology from FSMLabs, the creators of RTLinux. Lineo is the first to publicly license FSMLabs' technology, which was controversially granted a patent last year, and it is expected that other embedded operating system vendors may follow suit. Software patents in general are highly controversial, with some arguing that they are used to drive small competitors out of business. In the case of FSMLabs' patent, critics charged that the process patented, the so-called dual-kernel approach, is so obvious that one company should not be given ownership. The furore is an example of the complications that can arise in reconciling the popular open-source development model with businesses based on intellectual property. Complicating the matter, however, is the fact that FSMLabs is not looking to profit from the patent, unless licensees are themselves profiting. The distinction is important, because many developers use RTLinux or similar systems for non-commercial or research work. The licence gives Lineo the right to use FSMLabs' patented dual-kernel real-time technology, which allows the full capabilities of Linux to be made available without distracting from the real-time tasks important in robotics, medical instruments, network appliances and other embedded applications. FSMLabs chief executive Victor Yodaiken has said from the beginning that he hopes that the patent will stimulate development on the dual-kernel approach, and said that the Lineo deal should follow this pattern. "Our agreement with Lineo clears the way for both companies to innovate and broaden the market with superior technology and products," he said in a statement. The patent licence is complex, but Yodaiken says that it aims to allow open-source and GNU Public Licence-covered development work to continue, without endangering FSMLabs' ability to charge licence fees for its intellectual property. "We would like to find some way of using the patent to reinforce GPL, so that people don't take this method and build proprietary systems on it, without some additional licence," Yodaiken said in an interview with ZDNet sister publication LinuxDevices.com last August. Some observers, if they do not oppose the patent on principle, wonder if it can be enforced. One of the features covered by the patent, for example, is the method of running an operating system as a program within another, very simple real-time operating system (RTOS). The operations of the first OS can then be interrupted by the RTOS whenever tasks need to be carried out in "real" time -- that is, with as little delay as possible. "It seems rather easy to find evidence of prior art for the first technique described above," said software developer Jerry Epplin in a recent article on the subject. "Computing history is full of operating systems being run on top of operating systems." Software patents are also heatedly opposed on ideological grounds, although the most visible controversies have surrounded the patenting of software that facilitates business processes, rather than software that merely has a technical effect. The UK currently allows the latter, but not the former. Critics say that broader software patents, in line with US law, would be anti-competitive and disadvantage small and independent software developers. In the US, patents can be granted for more general business processes: online book retailer Amazon.com famously issued a lawsuit against arch rival Barnes and Noble for infringing on its patent for its 1-Click shopping process, which lets repeat shoppers purchase items without having to re-enter personal information. This spring the US court of Appeals for the Federal Circuit rejected Amazon's request for an injunction that would have stopped Barnes and Noble using a similar process on its own site. Other companies that have filed controversial patents in the US include Priceline.com, which holds a patent for its "name your own price" reverse auction procedure. The US patent office last year agreed to review its process for awarding such patents. In the UK, the patent office says that European law on what types of software processes can be patented is dangerously unclear. A spokesman said he believes this may have disadvantaged the software industry in Europe. See the Developer News Section for jobs and the latest headlines. See the Software News Section for full coverage. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Linux lounge forum Let the editors know what you think in the Mailroom. And read other letters.