For the first time ever, and probably only temporarily, Microsoft can be counted as a key contributor to Linux.
The company, which once portrayed the open source OS kernel as a form of cancer, has been ranked 17th on a tally of the largest code contributors to Linux.
The Linux Foundation's Linux Development Report, released on Tuesday, summarises who has contributed to the Linux kernel, from versions 2.6.36 to 3.2. The 10 largest contributors listed in the report are familiar names: Red Hat, Intel, Novell, IBM, Texas Instruments, Broadcom, Nokia, Samsung, Oracle and Google. But the appearance of Microsoft is a new one for the list, compiled annually.
Overall, Microsoft contributed 688 changes, or about 1.0 percent of the accepted changes to the kernel, since version 2.6.36. Company engineers also signed off on 2,174 changes, or about 1.1 percent of all the changes in this review period.
Much of the work Microsoft did centers around providing drivers for its own Hyper-V virtualisation technology. Microsoft's Hyper-V, part of Windows Server, can run Linux as a guest OS.
Linux kernel developer and LWN.net editor Jon Corbet, a co-author of the study, estimates that Microsoft's involvement peaked around last year's 3.0 release of Linux and will diminish over time. "Even the [hypervisor] drivers can only need so much cleaning up," he wrote in an article explaining the influx of Microsoft contribution.
For the Linux Foundation, Microsoft's involvement in Linux shows how widely used the OS kernel is these days. Microsoft must work with Linux to be part of the larger enterprise computing ecosystem.
In the time period covered by the report, more than 1,000 developers from nearly 200 companies contributed to the kernel. Lone contributors provided the largest number of changes, 11,413 changes or about 16.2 percent of all the changes in this review period. Among contributions from companies, Red Hat provided the most changes, or 7,563, or 10.7 percent of all changes. After Red Hat, Intel provided the next largest batch of changes, 5,075, or about 7.2 percent of all changes.
On average, between 8,000 and 12,000 patches are added to each new kernel release, which, overseen by Linus Torvalds, come out every two or three months. The vast majority of these changes are developed by outside parties.
In addition to Corbet, Linux kernel maintainer and Linux Foundation fellow Greg Kroah-Hartman and Linux Foundation Vice President of Marketing and Developer Services Amanda McPherson co-wrote the report.
The Linux Foundation is a non-profit organisation devoted to further developing and maintaining the open source Linux kernel. It is funded by companies that use Linux in their products and services, including HP, IBM, Intel, Novell and Oracle.