John Mauchly and John Presper Eckert , trying
to more quickly ascertain artillery shell trajectories for the
United States War Department, demonstrated ENIAC (Electronic Integrator
& Calculator) at the Ballistic Research Laboratory at the
Aberdeen Proving Grounds in Maryland. It is the first electronic
computer. It used punched cards for input and output. It was 100
feet long, consumed over 100 kilowatts of power in 18,000 electronic
valves. Its speed made made possible calculations which were so
tedious and time-consuming that they could not have been undertaken
previously.