Computer science development of sophisticated computing equipment. Wilhelm Schickard designed and constructed the first working mechanical calculator in 1623. In 1673, Gottfried Leibniz demonstrated a digital mechanical calculator, called the Stepped Reckoner. He may be considered the first computer scientist and information theorist, for, among other reasons, documenting the binary number system. In 1820, Thomas de Colmar launched the mechanical calculator industry when he released his simplified arithmometer, which was the first calculating machine strong enough and reliable enough to be used daily in an office environment. Charles Babbage started the design of the first "automatic mechanical calculator", his Difference Engine, in
Royal Radar Establishment Automatic Computer Atanasoff–Berry Computer in 1942. ENIAC was built in 1946 at the Moore School of Electrical Engineering at the University of Pennsylvania. ENIAC and Colossus both claim to be the world's first electronic computer. Electronic Delay Storage Automatic Calculator (EDSAC) ran its first programs on 6 May 1949 at the University of Cambridge Mathematical Laboratory about a month after the Manchester Mark 1 was put to research work at the University of Manchester. In May 1952 Geoffrey Dummer thought up the idea of the integrated circuit at the TRE, the former name of the RRE. By April 1962 there were 323