The “ball mouse” and Xerox

Although it was Engelbart who first developed the mouse, his former colleague, Bill English, was the one who took forward its development. Hence, while working in 1972 for Xerox in its already famous Palo Alto Research Park, English and Jack Hawley refined the design of Engelbart's mouse and added some interesting new features, the most important being the replacement of the two gear-system with a small metal ball, pressed against metallic rollers for tracking the movement. Another important innovation is related to the improvement of the interaction system with the computer, which now does not require anymore an analog-to-digital converter, instead sending digital positional information directly to the computer.

Despite the fact that English's design was quite advanced, it took Xerox around 9 years to actually refine it and streamline the manufacturing process as to allow it to become viable from the point of view of the costs involved.

Hence, in 1981, Xerox started mass-producing a commercial mouse for its 8010 Information System (aka the “Star”), which featured two buttons and ball tracking. However, the fact that the entire Star system sold for over $20,000 made it more or less obsolete, and with it, the mouse as well.