Richard Stallman Mellon's Mach microkernel in a project called GNU Hurd, which has yet to achieve the maturity level required for full POSIX compliance. In 1991, Linus Torvalds, a Finnish student, used the GNU's development tools to produce the free monolithic Linux kernel. The existing programs from the GNU project were readily ported to run on the resultant platform. Most sources use the name "Linux" to refer to the general-purpose operating system thus formed, while Stallman and the FSF call it "GNU/Linux". This has been a longstanding naming controversy in the free software community. Stallman argues that not using GNU in the
EPOC (operating system) system to drive their next generation of devices. First, however, they needed to engineer a 16-bit single-board computer—something that was extremely difficult at the time. They codenamed the project "SIBO", for "single-board organiser" or "sixteen-bit organiser". To develop the SIBO hardware and software, they needed samples of the 16-bit microprocessors they would be programming; but it took more than a year to secure the chips, which caused a significant delay. By 1987, development of EPOC was underway: It was a single-user, preemptive multitasking operating system designed to run in read-only memory (ROM). The operating system and its programmes were written