Such systems included features that could feed in a specified number of cards automatically. They could also add, multiply, and sort. They could even feed out cards with punched results. As compared to today's machines, these computers were slow, usually processing fifty to two hundred-twenty cards per minute, each card holding about eighty decimal numbers, or characters. At the time, however, punched cards were a huge step forward. They provided a means of input/output, and memory storage on a huge scale. For more than fifty years after their first use, punched card machines did most of the world's first business computing, and a considerable amount of the computing work in science. The start of World War II produced a large need for computer capacity, especially for the military. New weapons were made for which trajectory tables and other essential data were needed. In 1942, John P. Eckert, John W. Mauchly, and their associates at the Moore school of Electrical Engineering of University of Pennsylvania, decided to build a high-speed electronic computer to do the job. This machine became known as ENIAC (Electrical Numerical Integrator And Calculator). The size of ENIAC's numerical "word" was ten decimal digits, and it could multiply two of these numbers at a rate of three hundred per second, by finding the value of each product from a multiplication table stored in its memory. ENIAC was therefore about one thousand times faster then the previous generation of relay computers. ENIAC used eighteen thousand vacuum tubes, about one thousand-eight hundred square feet of floor space, and consumed about one hundred-eighty thousand watts of electrical power. It had punched card input/output, one multiplier, one divider/square rooter, and twenty adders using decimal ring counters, which served as adders and also as quick-access read-write register storage. The executable instructions making up a program wer...
