The Linux Foundation has released its annual report on the state of the software, and reports that Microsoft has made it into the Top 20 of companies that sponsor development of the Linux kernel – quite a change for the operating system Steve Ballmer used to dismiss as a cancer.

For contributions made to the kernel since version 2.6.36, Microsoft ranks 17th, with Redmond's contribution estimated at 1 per cent of the whole. The top contributing companies were Red Hat, Intel, and Novell. Samsung and Texas Instruments were also named as fast-growing contributors, reflecting an increase in interest in Linux for mobile and embedded systems.

"Linux is the platform for the future of computing. More developers and companies are contributing to the advancement of the operating system than ever before, especially in the areas of mobile, embedded and cloud computing," said Amanda McPherson, vice president of marketing and developer services for The Linux Foundation, in an emailed statement. "The increasing participation represents the power of Linux to quickly adapt to new market opportunities, lower costs, and provide sustained long-term support."

The report found that, contrary to arguments often made by commercial software houses (including Microsoft), the vast majority of Linux kernel development work is carried out by people paid by their employers to work on it. In all, the Linux Foundation estimates that 75 per cent of development work is done by salaried staff, even if they assume unknown volunteers are working on their own time.

Overall, the number of developers working on Linux has never been higher. Version 3.2 took code contributions from 1,316 developers, compared to 389 on version 2.6.11, and over 226 companies contributed to the latest release. ®