In 1890, Census Department employee Herman Hollerith borrowed Babbage's punch card idea to help tabulate U.S. Census information. As a result of these cards, the United States was able to complete the census in six weeks, years short of a previous estimate. Hollerith went on to establish the Tabulating Machine Company, better known today as IBM. Many such companies used punch card machines, processing 50-250 cards per minute, each card holding 80 characters. For more than 50 years, similar punch cards were used as a form of input, output, and memory storage.
Military needs propelled the evolution of computers forward. The first large-scale electronic computer was created for the military in 1942 at the University of Pennsylvania. This monster of a machine was known as the Electrical Numerical Integrator and Calculator (ENIAC). Consuming 180 kilowatts of power, occupying 1,800 feet of floor space, and using 18,000 vacuum tubes, the ENIAC was almost 1,000 times faster than any previous computer. It used punch cards to input and output data; registers served as memory storage. Though fully programmable, the ENIAC had to be rewired and switched for each new program. This flaw was fixed in 1947 with the appearance of the EDVAC and UNIVAC. These computers used random access memory, or RAM, to store programs and for data storage.
Early computers were slow, unreliable, and consumed an enormous amount of electrical power. This changed when Bell Laboratories introduced the transistor in 1948. The first generation of computers; namely, the ENIAC, EDVAC, and UNIVAC, all used vacuum tubes to represent data. These tubes consisted of a cathode and a plate suspended in a glass vacuum tube. Applying current to the tube would create a switch, the positive or negative voltage representing a 1 or a 0. The second-generation transistor (constructed of silicon) operated in a similar fashion; however, were smaller, consumed less energy, and cost less to produce.
