Primeiro Sistema Operativo (1973)

Alto, nome do primeiro programa operativo, foi criado pela XEROX para pesquisa. Embora tenham sido doados para várias organizações, XEROX Alto nunca chegou a ser comercializado. "The Xerox Alto was designed to be a relatively small, yet powerful, personal office computer with the ability to present information graphically, and to easily share information. They were also designed to utilize laser printers that were also under development at Xerox."