l electron tubes. This was quite an improvement over the earlier machines. The first-generation stored-program computers required considerable maintenance, usually attained 70% to 80% reliable operation, and were used for 8 to 12 years. Typically, they were programmed directly in machine language, although by the mid-1950s progress had been made in several aspects of advanced programming. This group of machines included EDVAC and UNIVAC, the first commercially available computers (Hazewindus, 102). The UNIVAC was developed by John W. Mauchley and John Eckert, Jr. in the 1950s. Together they had formed the Mauchley-Eckert Computer Corporation, Americas first computer company in the 1940s. During the development of the UNIVAC, they began to run short on funds and sold their company to the larger Remington-Rand Corporation. Eventually they built a working UNIVAC computer. It was delivered to the U.S. Census Bureau in 1951 where it was used to help tabulate the U.S. population (Hazewindus, 124). Early in the 1950s two important engineering discoveries changed the electronic computer field. The first computers were made with vacuum tubes, but by the late 1950s computers were being made out of transistors, which were smaller, less expensive, more reliable, and more efficient (Shallis...