The Atanasoffâ€“Berry computer (ABC) was the first automatic electronic digital computer ... the key principles of the ABC were conceived of in 1937. A working prototype was demo'd in October 1939 and was the first to implement three critical ideas that are still part of every modern computer: binary digits, electronic calculations, separation of computation and memory. The ABC played an important role in history; it was not a toy or academic curiosity -- it was designed to solve urgent PRACTICAL problems in statistical research and computations in physics that involve solving large systems of simultaneous equations.

Other milestones should be recognized... https://en.wikipedia.org/wiki/List_of_IEEE_milestones