The Linux Foundation's Linux Kernel Development report, also known as the "Who Writes Linux" report, which is now in its second year, tracks the development between kernel 2.6.24 to 2.6.30. Its findings were very interesting, indeed.
Since the first edition of the report last year, the net amount of contributed code to the Linux kernel was a staggering 2.7 million lines. About a third of these 2.7 million lines was comprised of the addition of the staging tree, adding nearly 800,000 lines of code that were previously out-of-tree.
This monumental net increase in code includes the subtraction of outdated code as well. Including weekends and holidays, an average of 5,547 lines were removed, 2,243 lines were changed, and 10,923 lines of code were added every day since 2.6.24. There were also an average of 5.45 patches added to the tree every hour, up from the previous average of 3.83. All of this is 42 percent faster than in the previous paper. According to the report, this rate of change is larger than any other public software project.
The work is being done by 1,150 developers, ten percent more than the 2.6.24 kernel had. Over the past four and a half years (between kernel 2.6.11 and now), a grand total of 4,190 individual developers contributed code. According to the report, though, "despite the large number of individual developers, there is still a relatively small number who are doing the majority of the work. In any given development cycle, approximately 1/3 of the developers involved contribute exactly one patch. Over the past 4.5 years, the top 10 individual developers have contributed almost 12 percent of the number of changes and the top 30 developers have contributed over 25 percent."
Some say it's a surprise, but I say it's natural that Linus Torvalds himself isn't the top contributor in changes over the past year. Since 2.6.24, he's made 254 changes while others contributed much more such as Red Hat kernel developer Ingo Molnar with 1,164 changes. It's only obvious that Linus now has a lot more on his plate than just a kernel to develop. Linux has become quite the empire, and he's doing a lot to direct it, as liquid and free as it is. There's every day life to consider, too; he's not a robot, after all. About Linus' contributions, the report said, "Linus remains an active and crucial part of the development process; his contribution cannot be measured just by the number of changes made." It also said that Linus is ninth in the list of managing kernel merges with 2.6 percent.
Company-wise, the top four contributing corporations are Red Hat with 12 percent of change contributions, IBM with 6.3 percent, Novell with 6.1 percent, and Intel at a round six. 21.1 percent of total changes since 2.6.24 were made by developers with no corporate affiliation whatsoever.
Overall, it seems like Linux is being developed to greater heights and at a faster and larger pace than really ever before. No wonder Microsoft is getting scared.