ENIAC, also known as Electronic Numerical Integrator and Computer was invented by John Presper Eckert and John Mauchly in 1946. After graduation John Mauchly joined John Presper Eckert at the University of Pennsylvania and they worked together to develop the ENIAC.
ENIAC was the first general purpose electronic digital computer to have been designed by humans. The machine was reprogrammable and could solve a number of computer problems. ENIAC was designed for calculating artillery firing tables for the United States Army’s Ballistic Research Laboratory, but was first used in hydrogen bomb calculations.
ENIAC computer had modules with separate panels for performing various functions. Out of these twenty were accumulators which could subtract, add and also store in its memory a ten-digit decimal number. ENIAC used 17,468 vacuum tubes, along with 10,000 capacitors, 70,000 resistors, 7,200 crystal diodes, 6000 manual switches, 1,500 relays and 5 million soldered joints. It weighed 30 tons and took up 1800 square feet of floor space and 150 kilowatts electric power.
Input was from an IBM card reader and an IBM card punch was used for output. ENIAC could perform 357 multiplications, 5000 additions or 38 divisions in one second. The use of vaccum tubes instead of relays and switches gave it a boost in speed.