page_title: AN/FSQ-7 Combat Direction Central
section_title: Equipment
hierarchical_section_title: AN/FSQ-7 Combat Direction Central / Equipment
caption_attribution_description: English: SAGE computer console at the Computer History Museum. Deutsch: SAGE-Computerkonsole im Computer History Museum.
context_page_description: The AN/FSQ-7 Combat Direction Central, referred to as the Q7 for short, was a computerized command and control system for Cold War ground-controlled interception used in the USAF Semi-Automatic Ground Environment air defense network.
  The name “AN/FSQ” derives from Army-Navy / Fixed Special eQuipment.
  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 weighed 250 tons. The AN/FSQ-7 used a total of 60,000 vacuum tubes and up to 3 megawatts of electricity, performing about 75,000 instructions per second for networking regional radars.
context_section_description: 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.  The Q7 had input/output devices such as:
  IBM 723 card punch and IBM 713 punched card reader
  IBM 718 line printer (64 print positions)
  drum auxiliary memory (50 "fields" of 2048 words each) and IBM 728 magnetic tape drives (32-bit words)
  Crosstelling Input (XTL) from other AN/FSQ sites
  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)
  Tracker Initiator Consoles for designating a "blip" (radar return) to be tracked (assign a track number and to relay speed, direction, and altitude)
  Command Post Digital Display Desk
  Senior Director's keyed console with the Bomarc fire button
  LRI Monitor Console for monitoring Long Range Radar data
  Large Board Projection Equipment 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.
caption: Maintenance Console
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