Over the past three years, the number of individual contributors to the Linux kernel has more than doubled to 1,057 for the most recent 2.6.24 kernel release.
According to a report out this week by the Linux Foundation, the pace of changes to the kernel also picked up, averaging 2.83 per hour over the course of 14 kernel updates during the 34-month period.
Meanwhile, the number of companies employing kernel contributors has broadened out as well, reaching 186 on Jan. 24, as the latest kernel came out, compared with 483 developers at 71 companies when the 2.6.11 kernel was released on March 2, 2005, according to a study produced by two kernel contributors, Greg Kroah-Hartman and Jonathan Corbet, as well as the spokeswoman for the Linux Foundation.
"No other open source project has gotten this large or moved this fast. It's a first-of-a-kind developer community," said IBM VP Dan Frye when asked to comment on the escalating kernel development process last November.
By reporting its statistics, the foundation is trying to provide visibility into who builds Linux and illustrate that it is a project that attracts broad support rather than being under the control of a few individuals or large companies. Linus Torvalds, originator of the Linux kernel, remains at the head of the development process and has final authority over additions to the kernel. Torvalds is employed by the foundation, a nonprofit organization to maintain a standard Linux kernel used in a variety of distributions. IBM, Intel, Hewlett-Packard, AMD, Fujitsu, and Oracle all have representatives on the board of directors, which includes Mark Shuttleworth, sponsor of the consumer-oriented Ubuntu distribution as well.
Red Hat remains the top contributor to Linux, with 11.2% of code contributions, but close on its heels is Novell with 8.9% and IBM at 8.7%.
Other companies high on the contributor list include Intel at 4.1%; the Linux Foundation through the developers it employs, 3.5%; SGI, 2%; MIPS Technologies, 1.6%; Oracle, 1.3%; MontaVista, a telecommunications distribution of Linux, 1.2%; Luntronix, 1%; and a group of companies all at 0.9%: HP, NetApp, SWsoft, Renesas Technology, Freescale, and Astaro.
Red Hat is at the top of the list thanks to two contributors who are its employees, Al Viro, with 1,571 changes in the most recent kernel, and David Miller with 1,520.
The third top individual contributor was Adrian Bunk of Movial, a Helsinki firm building software for mobile devices. "Movial found its way onto the list [of most active contributors] for the first time as a result of having hired [Bunk], a very active developer," Corbet noted in a Jan. 9 post to the Linux Weekly News, where he serves as executive editor.
Intel's position as the fourth-biggest corporate source of contributions "happened by virtue of the work done by four of the top-20 developers. ... Intel has a lot of people working on the kernel, many of whom spend little time in the limelight," Corbet wrote in the same posting.
Another point that the foundation is at pains to make in its report is that Linux is not a product of hobbyist activity, working in their basements at night. "Over 70% of all kernel development is demonstrably done by developers who are being paid for their work," concluded the report. In other words, they've been given full-time jobs to work on the kernel by companies with a vested interest in the kernel's ongoing development. For example, Torvalds right-hand lieutenant, Andrew Morton, is employed by Google.
Linux kernels are being released, each containing many changes, at an average rate of every 2.7 months. Red Hat and Novell, the suppliers of enterprise versions of Linux, wait for many kernel changes to mature and get tested by community members before adopting an updated kernel into the systems they sell.