Tuesday, 12 August 2014


The trackball, a related pointing device, was invented in 1946 by Ralph Benjamin as part of a post-World War II-era radar plotting technique called Comprehensive Display Technique (CDS). Benjamin was then working for the British Royal Navy Scientific Service. Benjamin's project used analog computers to calculate the future position of target aircraft based on several preliminary input points provided by a user with a joystick. Benjamin felt that a more elegant input device was needed and invented a ball tracker[5] called roller ball[6] for this purpose.

The device was patented in 1947,[6] but only a prototype using a metal ball rolling on rubber-coated wheels was ever built[5] and the device was kept as a military secret.[5]

Another early trackball was built by British electrical engineer Kenyon Taylor in collaboration with Tom Cranston and Fred Longstaff. Taylor was part of the original Ferranti Canada, working on the Royal Canadian Navy's DATAR (Digital Automated Tracking and Resolving) technique in 1952.[7]

DATAR was similar in idea to Benjamin's display. The trackball used disks to select up motion, each for the X and Y directions. Several rollers provided mechanical support. When the ball was rolled, the pickup discs spun and contacts on their outer rim made periodic contact with wires, producing pulses of output with each movement of the ball. By counting the pulses, the physical movement of the ball could be determined. A digital computer calculated the tracks, and sent the resulting knowledge to other ships in a task force using pulse-code modulation radio signals. This trackball used a standard Canadian five-pin bowling ball. It was not patented, as it was a secret military project as well.

Early mouse patents. From left to right: Opposing track wheels by Engelbart, Nov. 1970, U.S. Patent three,541,541. Ball and wheel by Rider, Sept. 1974, U.S. Patent three,835,464. Ball and rollers with spring by Opocensky, Oct. 1976, U.S. Patent three,987,685

Independently, Douglas Engelbart at the Stanford Research Institute (now SRI International) invented his first mouse prototype in the 1960s with the help of his lead engineer Bill English.[10] They christened the device the mouse as early models had a cord attached to the rear part of the device looking like a tail and usually resembling the common mouse.[11] Engelbart seldom received any royalties for it, as his employer SRI held the patent, which ran out before it became widely used in personal computers.[12] The invention of the mouse was a small part of Engelbart's much larger project, aimed at augmenting human intellect by the Augmentation Research Middle.

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