In 1978, Xerox donated fifty Altos to Stanford, Carnegie-Mellon, and MIT (Massachusetts Institute of Technology). These machines featured a revolutionary concept called WIMP for Window Icon Mouse Pointer which wil become, a few years later, a universal standard for all of our modern computers.
The idea of a graphical interface was born 5 years earlier at Xerox PARC (Palo Alto Research Centre) as a part of an "automated office of the future" project. Within two years, engineers invented all the basic concepts of a new Human-Computer interface: the Graphical User Interface with a bitmap screen display, windows, icons and drop-down menu bars, the mouse, but also Ethernet protocols for local area networks, the Smalltalk programming language and a software productivity suite with a word processor, paint program, and even email.
The first technical achievement was the Alto, a 64K machine which featured all of the above concepts. It was launched in 1974 but didn't meet success because of its $40.000 high price. Remember that at this time, none of the well known first personal computers (Imsai, Apple, Tandy, Commodore...) existed.
In 1981, Xerox presented the successor of the Alto. The Star was a 512K machine dedicated to groups working together with integrated and interconnected components that shared mail, printing and filing. However nobody knew what that meant! Sharing information and communicating were foreign to the IBM-PC culture. Thus Xerox gave up on the project. The Alto-Star designers left the company and joined Apple or Microsoft.
In 1979 Steve Jobs saw the Alto and realized it was the future of computing. Many of the ideas in the Alto showed up two years later in the Apple Lisa, and finally made it to market in the Apple Macintosh.
In 1983, the first (and later) version of Microsoft Windows was also strongly inspired from the Alto concepts.