Over the last three years, the number of developers of the Linux kernel has tripled, according to the Linux Foundation. A research team from the organization has reported that the growth of the open source operating system into new areas is attracting more hands-on code writing of the Linux engine. The kernel forms the core of the Linux system and is the result of one of the largest cooperative software projects ever attempted, according to the three Linux Foundation researchers. The Linux Foundation issued the report this month.