Red Hat, IBM and Novell are the three companies that contribute the most to Linux kernel development. A new report from the Linux Foundation says, however, that despite the contributions of these three companies, it is still non-affiliated individual developers that make up the most significant contribution to the ongoing development of a kernel which grows by more than 5 000 lines of code a day.

According to the report, individual developers (18.2%) and those not explicitly identified as working for a company (7.6%) have made 25.8% of the changes to the 2.6.x kernel to date, or a total of 37 808 changes. Red Hat developers contributed 17 981 (12.3%) changes to the same code base. IBM’s team, the second largest corporate contributor, accounted for 11 151 (7.6%) changes to the kernel.

The top ten contributors to the kernel are:

1 – None (18.2%)
2 – Red Hat (12.3%)
3 – Unknown (7.6%)
4 – IBM (7.6%)
5 – Novell (7.6%)
6 – Intel (5.3%)
7 – Consultant (2.5%)
8 – Oracle (2.4%)
9 – Linux Foundation (1.6%)
10 – SGI (1.6%)

According to the report the average kernel development cycle runs for 81 days, just shy of 12 weeks. The 2.6.12 and 2.6.24 kernels had the longest cycles at 108 days each. The shortest cycle was for the 2.6.14 release at just 61 days.

Growing quickly

With all these contributions to the code base it’s unsurprising that the Linux kernel has grown significantly in size. The 2.6.11 version of the kernel had 17 090 files and 6 624 076 lines of code. The 2.6.30 kernel has 27 911 files and 11 560 971 lines of code.

Even more interesting is the rate at which the kernel is developing and changing form. In the 2.6.11 kernel there were an average of 3 224 lines added, 11 360 lines deleted and 1 290 lines altered each and every day of the year.
This pace has stepped up since the 2.6.24 release and now averages 10 923 lines added, 5 547 lines deleted and 2 243 lines changed every day.

The full report can be downloaded from the Linux Foundation website.