Three machines have been promoted at various times as the
first electronic computers. These machines used electronic
switches, in the form of vacuum tubes, instead of
electromechanical relays. In principle the electronic switches
would be more reliable,
since they would have no moving parts that would wear out,
but the technology was still new at that time and the tubes
were comparable to relays in reliability. Electronic
components had one major
benefit, however: they could ``open'' and ``close'' about 1,000
times faster than mechanical switches.
The earliest attempt to build an electronic computer was by J. V. Atanasoff, a professor of physics and mathematics at Iowa State, in 1937. Atanasoff set out to build a machine that would help his graduate students solve systems of partial differential equations. By 1941 he and graduate student Clifford Berry had succeeded in building a machine that could solve 29 simultaneous equations with 29 unknowns. However, the machine was not programmable, and was more of an electronic calculator.
