1. ENIAC Electronic Numerical Integrator and Computer

2. ENIAC

3. ENIAC (Electronic Numerical Integrator and Computer) Finished: February 1946. Used until 1955. ENIAC’s physical size was massive. It contained 17,468 vacuum tubes and 70,000 resistors, and weighed 30 tons. ENIAC was roughly 1800 square feet in size and consumed 174 kilowatts of power. Memory: 20 accumulators each holding 10-digit decimal numbers. A ring of 10 vacuum tubes represented each digit An IBM card reader was used for input, and an IBM card punch machine was used for output. The punched cards could be used to produce printed output offline using an IBM tabulating machine. ENIAC could churn 5,000 addition problems in one second, far faster than any device yet invented. Programming: manual by setting switches and connecting cables.

4. ENIAC