The computer operating systems (OS) map presents functions of Operating Systems and comparison of all major OS. It also provide compelete history of computer OS development since the inception of computers in 1950' till now. More details of timeline of UNIX and UNIX-lie OS, IBM OS, Microsoft and Apple OS are also displayed. A comprehensive computer operating system (OS) guide and reference for IT professionals and everyone interested in computer OS technologies and its history. Functions of Operating Systems and comparison of all major OS available now. Complete history of computer OS development since the inception of computers in 1950' till now. Timeline of UNIX and UNIX-like operating systems, such as AT&T UNIX, HP and SUN UNIX versions, LINUX etc... Timeline of Microsoft OS evolution from DOS to Windows Vista. Timeline of IBM OS technologies for both mainframes and Desktops. Timeline of Apple computer OS development. Designed by experts with decades of experience in the computing industry.