SAGE (Semi-Automatic Ground Environment) had a fundamental impact on the development of computers and the computer industry. When the program began, work on the first digital computer, MIT's Whirlwind, was in progress. Key to the success of SAGE was the development of a production version of MIT's prototype Whirlwind computer. A little known company called IBM won the contract to design and build the Whirlwind II, otherwise known as AN/FSQ-7, for the proposed new air defense system.

		It may be difficult to believe, but at one time, 20 percent of the world's programmers were working on a single project. The year was 1953 and this mammoth task was known as the SAGE system a continental air-defense network commissioned by the U.S. military. Over the course of its ten-year development, SAGE was the most ambitious computer project ever undertaken, one that occupied over 800 programmers and the technical resources of some of America's largest corporations. Strangely enough, few people in the computer business now even know it existed. Born of cold war hysteria and a military-industrial-academic complex, SAGE was the brainchild of Jay Forrester and George Valley, two MIT professors at that school's Lincoln Lab. SAGE project development was a strange affair, the outgrowth of a flight simulator project that used first analog, then digital, computing techniques. As project funding and goals changed, Forrester and his military backers underwent a process of mutual alignment to keep some kind of digital computing expertise alive.
Vector display with geographical reference marks. A Whirlwind I computer generates and displays aircraft positions and auxiliary information.

In a long 1948 report, Forrester laid out a plan to improve America's air defense using techniques learned from W.W. II radar development (MIT had become the center of that field's development). After many fits and starts, changes in project direction and focus, the system that emerged was composed of 23 concrete-hardened bunkers across the United States (and one in Canada) linked into a continental air-defense system. SAGE would detect atomic bomb-carrying Soviet bombers and guide American interceptors to destroy the invaders. It could also be linked to nuclear-tipped Bomarc and Nike missiles. Each of the 23 SAGE "Direction Centers" housed a computer (known as the "A/N FSQ-7") that consumed 3MW (megawatts!) of power, had approximately 60,000 vacuum tubes, and took over 100 people to operate. The total project cost is still classified, though it's estimated to have been between 8-12 billion in 1964 dollars, many times the cost of the Manhattan Project that developed atomic weapons initially.
		SAGE Sector Control Room. The screen shows the US eastern seaboard from the extreme west end of Nova Scotia.

		Four main contractors were responsible for SAGE: IBM for hardware; Burroughs for inter-Center communications (modems); MIT's Lincoln Lab (later MITRE Corporation) for system integration; Western Electric for design & construction of buildings; and SDC a spin-off of the RAND Corporation for software. The first SAGE Direction Center came online in November of 1956, the last in 1962. When the final SAGE Direction Center was dismantled (the Canadian one mentioned previously, in 1983). The SAGE system was fully deployed in 1963; the 24 SAGE Direction Centers and three SAGE Combat Centers were spread throughout the U.S. Each was linked by long-distance telephone lines to more than 100 interoperating air defense elements, requiring system integration on a scale previously unimagined. At the heart of each center was a new large-scale digital computer that had evolved from MIT's experimental Whirlwind computer of the 1950's. The largest real-time computer program of that time, it automated information flow, processed and presented data to 100 operator stations, and provided control information to the weapons systems.
SAGE close-up display output shown weapon ranges (circules) and aircraft ID tags (digits) from a early 1950s documentary film.

A 19" Charactron (Developed by Hughes Products Co.) cathode-ray-tube displays geographically oriented data covering the whole or part of the sector. On this air situation display scope, the operator can view different categories of tracks or radar data, geographical boundaries, predicted interception points, or special displays generated by the computer to assist his decision. Every two and one half seconds, the computer generates about two hundred different types of displays requiring up to 20,000 characters, 18,000 points and 5,000 lines. Some of these are always present on an operator's situation display. Others he may select. Some he may request the computer to prepare especially for his viewing. Finally, the computer can force very high priority displays for his attention.
		A early mid-1950s documentary explains the SAGE system.

		This processed information, including aircraft tracks and identification, was presented to operators on a cathode ray tube - one of the first uses of this device to display computer-generated data. Jim Wong, a software engineer on the SAGE project notes: " 'It was first done in SAGE.' For many, many years those were the words said in industry. SAGE was the real-time, command and control computer-based system with capability so advanced that 40 years later, today, some of that capability can still be called state of the art." Along with training a generation of computer people, the SAGE project also brought in some $500 million for IBM, the principal contractor. It is possible that without this source of revenue, IBM may not have had the financial strength, or even technical know-how, to develop the System/360 series of computers the single most successful computer architecture of all time (over $100 billion worth of systems).
1962 Sagebro - The SAGE Computer, IBM Federal Systems Division.