Sarah Dow
History of computing
Way back in early history, when people relied mainly on their brains to perform calculations, people used their fingers, pebbles, and tally sticks for computing purposes.
Various attempts were made to build general-purpose programmable computers from the same mechanical devices used in calculators. But the problems posed by the lack of technology at the time were not satisfactorily solved until the introduction of electronic computing techniques in the mid-20th century. Between Pascal's invention and around 1820 there were about 25 manufacturers of calculating machines; most of them were the work of one man. Few of them worked correctly and even less actually reached the manufacturing line.
In the mid-19th century Charles Babbage, a visionary British mathematician at Cambridge University, designed the first computers to perform multistep operations automatically.
The technologies were entirely mechanical. He called this first computing machine the Difference Engine, and it was intended to compute and print mathematical tables automatically. The Difference Engine performed only one arithmetic operation: addition. Babbage constructed a small portion of his first Difference Engine in 1832, which served as a demonstration prototype.