ExtremeTech wrote an article about who actually develops Linux. The answer is that the majority of code contributions to the Linux kernel are made by commercial companies, the three most active being Red Hat, Intel and Texas Intruments. The latest report frmo the Linux Foundation mentions that the number of unpaid developers contributing to the Linux kernel has been slowly declining for many years, now sitting at just 13.6 percent (versus 14.6 percent in the last report).
Unsurprisingly, Red Hat — one of the very few open-source Dot Com success stories — rules the roost. The Linux Foundation reports that, over the past year, there has been a sizable increase from companies that make mobile and embedded systems (Samsung, Texas Instruments, Linaro). In the previous report, these three companies contributed just 4.4% of the kernel changes — this year, it’s up to almost 11%. Linaro, if you haven’t heard of it, is a not-for-profit company set up by ARM, Freescale, IBM, Samsung, ST-Ericsson, and Texas Instruments, for the sole purpose of improving Linux’s ARM support. Non-profit doesn’t mean Linaro developers don’t get paid a lot of money, however.