ABC or "Atanasoff-Berry Computer" is now regarded as the first prototype of the "computer"
as a machine containing only the electronic components with no moving mechanical components.
Constructed by John Atanasoff'a and Clifford Berry
In 1939 a cost of USD 650 contemporary.

It was the size of a desk, worked very slowly
and required constant supervision of human operator,
but it was about 1000 times faster than the used machines.