ENIAC(Electonic Numerical Integrator And Computer)

In the true sense,the first electronic computer was developed by John Mauchly and John Presper Eckert.It was developed at the University of Pennsylvania and called ENIAC(Electronic Numerical Integrator And Computer).ENIAC used high speed vacuum tubes(switching devices).The high speed operation of the computer in the world was first experienced with ENIAC.It could add two numbers in 200 micro seconds and multiply two numbers in 2800 micro seconds.Number of vacuum tubes used was 19,000.It occupied an area of 150 square meters.In fact,ENIAC was the result of the US armed force to complete new trajectory tables for use in World War second.But ENIAC was complete in 1946.So they could not make use of it in war.
Even though it was fast there were few drawbacks in ENIAC.Those were:

1)Large amount of heat generated by vacuum tubes needed a cooling facility.
2)Storage capacity was small.
3)Whenever the program is changed,the machine had to be rewired.