The AN/FSQ-7 Combat Direction Central, referred to as the Q7, was a computerized air defense command and control system. It was used by the United States Air Force for ground-controlled interception as part of the Semi-Automatic Ground Environment (SAGE) network during the Cold War. The JETDS system also now is used to name all Department of Defense electronic systems.

An advancement of the pioneering MIT Whirlwind II digital computer design, and manufactured by IBM as prime contractor, the AN/FSQ-7 was the largest discrete computer system ever built. Each of the 24 installed machines (49,000 in the computers) method used in manual command post operations.

The Q7 fire button launched the Bomarc, and an additional Q7 algorithm automatically directed the missile during climb and cruise to the beginning of its supersonic dive on the target when guidance transferred to the missile seeker system for the homing dive.

The AN/FSQ-7 was based on the larger and faster (but uncompleted) Whirlwind II design.

DC-1 at McGuire Air Force Base was the first operational site of the AN/FSQ-7 where the "electronic brain" began arriving in November 1958. The Cape Canaveral BOMARC 624-XY1's intercept of a target drone in August 1958 used the Kingston, New York, Q7 By 1959, the 2000th simulated BOMARC intercept had been completed by the Q7.

The SAGE/Missile Master test program conducted large-scale field testing of the ATABE mathematical model using radar tracks of actual Strategic Air Command and Air Defense Command aircraft conducting mock penetrations into defense sectors (cf. Operation Skyshield). The vacuum-tube SAGE network was completed (and obsolete) in 1963, and a system ergonomic test was performed at Luke Air Force Base in 1964. According to Harold Sackman, it "showed conclusively that the wrong timing of human and technical operations was leading to frequent truncation of the flight path tracking system." two remained at SAGE sites until 1983 and the Q7 at Luke AFB was demolished in February 1984.

Sabre

The SABRE airline reservation system used AN/FSQ-7 technology.

Q7 components were used as props in numerous films and television series needing futuristic-looking computers, despite the fact they were built in the 1950s. Q7 components were used in The Time Tunnel, The Towering Inferno, Logan's Run, WarGames, Independence Day, Planet of the Apes TV series (Season 1, Episode 5, "The Legacy" aired October 1974), and many others.

Today

The Computer History Museum displays several AN/FSQ-7 components.

Equipment

thumb|right|Situation Display console and other parts at [[Computer History Museum ]]

right|thumb| The AN/FSQ-7 had 100 system consoles, including the OA-1008 Situation Display (SD) with a [[light gun (at end of cable under plastic museum cover), cigarette lighter, and ash tray (left of the light gun).]]

right|thumb|Maintenance Console

MIT selected IBM as the prime contractor for equipment construction.

The Central Computer System of the AN/FSQ-7 had two computers for redundancy each with Arithmetic, Core Memory, Instruction Control, Maintenance Control, Selection & IO Control, and Program elements.

  • Display and Warning Light System with dozens of consoles in various rooms having Situation Display Tubes, Digital Display Tubes, and controls (e.g., push buttons and light gun) including:
  • Duplex Maintenance Console (two), each DMC operated one of the Central Computer Systems and allowed diagnostics (a speaker was available)
  • Command Post Digital Display Desk Operator displays were directly copied on 35 mm film which were projected on the board.

Punched card data was transferred to and from the core memory as binary images. Only the rightmost 64 columns were transferred, with each row containing two 32-bit words. (The left columns could be punched using a special instruction.) Data were transferred to the line printer as a card image as well.

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