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
Computer terminal access to a distant "terminal host" system. The terminal of the first working programmable, fully automatic digital Turing-complete computer, the Z3, had a keyboard and a row of lamps to show results. Early user terminals connected to computers were electromechanical teleprinters/teletypewriters (TeleTYpewriter, TTY), such as the Teletype Model 33 ASR, originally used for telegraphy or the Friden Flexowriter. Later printing terminals such as the DECwriter LA30 were developed. However printing terminals were limited by the speed at which paper could be printed, and for interactive use the paper record was unnecessary. By the early 1970s, many users in the computer