"The GNU operating system is a complete free software system, upward-compatible with Unix. GNU stands for “GNU's Not Unix”. Richard Stallman made the Initial Announcement of the GNU Project in September 1983. A longer version called the GNU Manifesto was published in September 1985 [...] By 1990 we had either found or written all the major components except one—the kernel. Then Linux, a Unix-like kernel, was developed by Linus Torvalds in 1991 and made free software in 1992. Combining Linux with the almost-complete GNU system resulted in a complete operating system: the GNU/Linux system..."