In 1941, Konrad Zuse built a programmable electromechanical computer, called the Z3 machine, that understood binary encoding and floating point numbers.
The Atanasoff–Berry computer (ABC) was the first automatic electronic digital computer. Key principles of the ABC were conceived in 1937; an 11-tube prototype was first demonstrated in October 1939. The machine was not Turing complete, but it was the first to implement three critical ideas that are still part of every modern computer:
1) Using binary digits to represent all numbers and data
2) Performing all calculations using electronics rather than wheels, ratchets, or mechanical switches,
3) Organizing a system in which computation and memory are separated.
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