A cross section of the Linux community signaled last week that it's time to get back to work on the open source operating system and move past Microsoft's patent deals and claims of infringement. Lawyers can quibble, but it's up to the community to expand the system's capabilities and maintain its momentum.

The occasion was the Linux Foundation Collaboration Summit, an event organized by the Linux Foundation, a San Francisco-based group that includes Advanced Micro Devices, Bank of America, EMC, Intel, Hewlett-Packard, IBM, Oracle, and Novell. It was staged on Google's Mountain View, Calif., campus for 200 open source developers, users, and software vendors. The get-together included speeches, panel discussions, and a question-and-answer session with six Linux kernel developers.

Dan Frye, IBM's VP of open systems development, said IBM-sponsored developers are focused on advancing Linux as a real-time operating system, especially for defense and financial services customers. Linux vendor Red Hat and IBM said in March that they were working together on such a version. Novell's SUSE Linux has been available in a real-time version since October. Smaller vendors MontaVista and Concurrent also offer real-time Linux distributions.

Wall Street wants real-time Linux for systems that make trading decisions within fractions of a second, Frye said. Real-time Linux also could play a role in manufacturing, where monitoring systems must react quickly to changing temperatures, and in hospitals in systems that monitor patients' vital signs, he said.

Starting with release 2.4 and then 2.6 of the Linux kernel, Linus Torvalds and company have been issuing updates every two to three months. "We add 2,000 lines of code a day to the Linux kernel. We work on 2,800 lines of code a day," said kernel developer Greg Kroah-Hartman. "I've never seen the pace of change that Linux has shown."

That presents its own problems. When new features are added to the kernel at that pace, they haven't necessarily been tested with all the requisite software and on the requisite systems. A questioner asked the kernel developers why they didn't engage in more regression testing, making sure a new kernel runs the same as the previous kernel in the same environments.

"There's a tension between introducing new features and stabilizing them," said James Bottomley, who works on the Linux kernel and also is CTO at SteelEye Technology. With developers committed to speeding up the pace of innovation, "what we really need is for the user community to help us track down bugs," he said. "The user base is far bigger than the number of kernel developers."