When the Soviet Union detonated their first atomic bomb on August 29, 1949, the United States government concluded that it needed a real-time, state-of-the-art air defense system. It turned to Massachusetts Institute of Technology (MIT), which in turn recruited companies and other organizations to design what would be an online system covering all of North America using many technologies, a number of which did not exist yet. Could it be done? It had to be done. Such a system had to observe, evaluate and communicate incoming threats much the way a modern air traffic control system monitors flights of aircraft.
This marked the beginning of SAGE (Semi-Automatic Ground Environment), the national air defense system implemented by the United States to warn of and intercept airborne attacks during the Cold War. The heart of this digital system—the AN/FSQ-7 computer—was developed, built and maintained by IBM. SAGE was the largest computer project in the world during the 1950s and took IBM squarely into the new world of computing. Between 1952 and 1955, it generated 80 percent of IBM’s revenues from computers, and by 1958, more than 7000 IBMers were involved in the project.
At 250 tons and 60,000 vacuum tubes, the SAGE system was the largest, heaviest
and most expensive computer system ever built!