Monday, May 25, 2009

The Mother of All PCs

Electronic Numerical Integrator And Computer (ENIAC)
Trace the lineage of that PC portable on your lap, and you’ll find the Electronic Numerical Integrator And Computer (ENIAC) at the base of the family tree. ENIAC was the first large-scale, general purpose, and a digital computer. ENIAC was initially built for the United States military to calculate the paths of artillery shells. It was later used to make calculations for nuclear weapons research, weather prediction, and wind tunnel design. ENIAC began operating in February 1946 and was used until October 1955. ENIAC was built by American physicist John W. Mauchly and American electrical engineer John Presper Eckert, Jr., at the Moore School of Electrical Engineering, University of Pennsylvania. Unlike modern computers, which use microprocessors composed of thousands or millions of transistors, ENIAC used vacuum tubes to process data. It had about 18,000 vacuum tubes, each the size of a small light bulb, 70,000 resistors, and 6000 switches. The computer was composed of 30 separate units with additional power supplies and cooling units. It weighed more than 30 tons, occupied 1800 sq ft and consumed 175 kw of power. ENIAC contained 20 special storage registers called accumulators that stored intermediate and final calculations. Each accumulator held a ten-digit number. ENIAC used decimal arithmetic in its operations rather than the binary arithmetic common in today’s computers. ENIAC could perform about 5000 calculations per second—more than 10,000 times slower than modern personal computers. And it was probably the first computer to use the conditional IF-THEN statement. A straight line runs from ENIAC to UNIVAC of 1951 (one of the first commercial computers), to the IBM PC, to Palm Pilot in your pocket. The ENIAC is the mother of all PCs.