The United States government developed SAGE (Semi-Automatic Ground Environment) as the strategic defense against potential air attacks by the Soviet Union during the Cold War of the 1950s and '60s. The U.S. Air Force selected IBM to manufacture a breakthrough computer to serve as the backbone for a real-time, data-intensive air defense system.
In collaboration with professors from Massachusetts Institute of Technology and personnel from other major U.S. companies, IBM developed the AN/FSQ-7 computer. It powered an effort that was unprecedented in functional scope, geographic reach, speed of information processing and accuracy, and enabled through remarkable reliability. To make a computer—a relatively new technology—fully operative and reliable, not only for days or months, but years, was an extraordinary challenge.
In the 1950s, SAGE was not only the largest computer project in the world, but also the most advanced: it brought forth numerous innovations that are commonplace in today’s computers. SAGE would become a platform for a series of new, equally groundbreaking IBM products that were dominant computing standards: the IBM 704, which improved upon the magnetic core memory in SAGE; tape storage; FORTRAN, the first commercial high-level computer programming language; and the IBM System/360.
The SAGE collaborative produced an array of inventions in data processing and communications hardware used across a new “distributed system” of real-time information, now known as a network. When fully deployed in 1963, SAGE operated across 27 locations via modems and 25,000 telephone lines (using digital-analog and analog-digital conversions). The system displayed “interactive computer graphics,” often executed by a light gun aimed at a screen.
SAGE was an instrumental project for the U.S. Department of Defense, demonstrating the government’s ability to coordinate large-scale, diversified, and highly sophisticated computer research and development projects on a fast track. SAGE cost estimates range from US$4 billion to $12 billion, with US$8 billion a common estimate. Included were 56 IBM computers at US$30 million each.