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
Operating system ROM and known as "monitors". One notable early disk operating system was CP/M, which was supported on many early microcomputers and was closely imitated by Microsoft's MS-DOS, which became widely popular as the operating system chosen for the IBM PC (IBM's version of it was called IBM DOS or PC DOS). In the 1980s, Apple Computer Inc. (now Apple Inc.) abandoned its popular Apple II series of microcomputers to introduce the Apple Macintosh computer with an innovative graphical user interface (GUI) to the Mac OS. The introduction of the Intel 80386 CPU chip in October 1985, with 32-bit architecture and