Semi-Automatic Ground Environment

The Semi-Automatic Ground Environment (usually referred to by the acronym, SAGE) of the USA was a computerised air defense system; the earliest distributed real-time system. It used the Whirlwind machine (suitably augmented) as a prototype.

The hardware, the AN/FSQ-7, was designed by IBM, in cooperation with Lincoln Laboratory, and built by IBM (and was a significant factor in their growth in expertise in computers). The software was begun by Lincoln, but the effort was taken over by the Rand Corporation, whose System Development Division (where the work was done) grew so large that in November, 1956, it was spun off as the non-profit System Development Corporation. MITRE was also created by the SAGE effort, in July, 1958, as a spin-off of Lincoln, to help take the system to completion.

Whether SAGE would have actually worked, if called upon to do so, is unclear; but the side-effects, in improvements to computers, were immense.

Further reading

• Kent C. Redmond, Thomas M. Smith, From Whirlwind to MITRE: The R&D Story of the SAGE Air Defense Computer, MIT Press, Cambridge, 2000
• John F. Jacobs, The SAGE Air Defense System: A Personal History, MITRE Corporation, Bedford, 1986
• Special Issue - SAGE (Semi-Automatic Ground Environment), Annals of the History of Computing, Vol. 5, No. 4, October 1983

External links

• sage - documentation at Bitsavers
  • Introduction to AN/FSQ-7 (C686-416L-ST) - contains a good overview of SAGE
  • The Computer Museum Member's First Field Trip To Northbay AN/FSQ-7 SAGE Site
• Final Report of PROJECT CHARLES - the effort that started SAGE rolling
• SAGE: Semi-Automatic Ground Environment Air Defense System - good, fairly detailed history
  • Reflections on SAGE
• SAGE: Semi-Automatic Ground Environment Air Defense System - older version, with more details
  • A New Threat
  • Lincoln Laboratory Origins
  • Lincoln Laboratory Origins (part 2)
  • The SAGE Air Defense System
  • Early Digital Computing
  • Early Digital Computing (part 2)
  • Cape Cod SAGE Prototype
  • Cape Cod SAGE Prototype (part 2)
  • Early-Warning Radars
  • Part 2: MIT Lincoln Laboratory develops UHF early-warning radar
  • Part 3: Jug Handle, Boston Hill, and Texas Tower radars
  • SAGE Transition - covers the creation of MITRE
  • Reflections on SAGE
• Milestones: SAGE—Semi-Automatic Ground Environment, 1951-1958
• Introduction to AN/FSQ-7 Combat Direction Central and AN/FSQ-8 Combat Control Central - good detailed technical overview
• Stories about SAGE
  • IBM SAGE
• “This Is Only a Test” - interesting description of full-scale tests of SAGE
• The Never-Before-Told Story of the World's First Computer Art (It's a Sexy Dame)