1978: BSD - History of Desktop OSs
BSD (Berkeley Software Distribution) is remembered as the origin of the open source operating system and drove an idea that would power community maintained software in parallel to traditional commercial operating systems.
Bill Joy, who later went on to co-found Sun Microsystems, created the first major variant to emerge from UNIX and, after its discontinuance in 1995, resulting in derivates such as FreeBSD, NetBSD, DragonFly BSD and OpenBSD. BSD also forms the core of Apple's Mac OS X operating system. BSD is still available today, but has little visibility on the mainstream desktop and has greater influence on computers used especially by universities.