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
Cray Operating System 1.17 is available at archive.org. Cray Operating System The Cray Operating System (COS) succeeded Chippewa Operating System (shipped with earlier computer systems CDC 6000 series and CDC 7600) and is Cray Research's now discontinued proprietary operating system for its Cray-1 (1976) and Cray X-MP supercomputers, and those platforms' main OS until replaced by UNICOS in the late 1980s. COS was delivered with Cray Assembly Language (CAL), Cray FORTRAN (CFT), and Pascal. As COS was written by ex-Control Data employees, its command language and internal organization bore strong resemblance to the SCOPE operating system on the CDC 7600 and before that