The decreasing cost of display equipment and processors made it practical to provide graphical user interfaces for many operating systems, such as the generic X Window System that is provided with many Unix systems, or other graphical systems such as Apple's classic Mac OS and macOS, the Radio Shack Color Computer's OS-9 Level II/MultiVue, Commodore's AmigaOS, Atari TOS, IBM's OS/2, and Microsoft Windows. The original GUI was developed on the Xerox Alto computer system at Xerox Palo Alto Research Center in the early 1970s and commercialized by many vendors throughout the 1980s and 1990s.