AN/FSQ-7 Combat Direction Central

The AN/FSQ-7 Combat Direction Central, known as the Q7, was a very special kind of computerized system used for air defense. It helped the United States Air Force control and direct airplanes during times of tension, especially during the Cold War. This system was a big part of something called the Semi-Automatic Ground Environment (SAGE) network, which linked many radars and computers together.

The name "AN/FSQ-7" follows a special naming system called the Joint Electronics Type Designation System. This system is used by the Department of Defense to give names to electronic equipment. The "AN/FSQ-7" means it was the 7th design of a special electronic device for the Army and Navy.

The AN/FSQ-7 was based on an early computer design from MIT called the Whirlwind II. IBM, a big technology company, built these machines. It was the largest discrete computer system ever made. Each of the 24 machines built weighed 250 tons. These computers used 60,000 vacuum tubes and needed up to 3 megawatts of electricity to run. They could perform about 75,000 instructions per second, which was amazing for their time.

Primary functions

The AN/FSQ-7 computers were used in the USAF Semi-Automatic Ground Environment network for air defense. They worked in pairs, with one active and one on standby, to ensure reliability. The system helped plan where airplanes or CIM-10 Bomarc missiles should intercept enemy aircraft.

It also launched the Bomarc missiles and guided them until they were close to their target, after which the missile would guide itself.

History

The first United States radar network used voice reporting to the Twin Lights Station in New Jersey, and after World War II, the experimental Cape Cod System used a Whirlwind I computer in Cambridge, Massachusetts to connect different types of radars. A key improvement in the Whirlwind I was the creation of magnetic-core memory, which made the system more reliable and much faster.

The AN/FSQ-7 was developed from a larger plan called Whirlwind II, but it was too big for MIT to handle alone. So, IBM became the main builder, with help from the MIT Lincoln Laboratory. Around the same time, a smaller system called the AN/FSQ-8 Combat Control Central was also made. A simpler version of the AN/FSQ-7 was set up at the System Development Corporation in Santa Monica, California from 1957 until the place was left empty after 1981.

Uses

SAGE

Main article: Semi-Automatic Ground Environment

The AN/FSQ-7 was an important part of the Semi-Automatic Ground Environment (SAGE) network, which helped guide airplanes during the Cold War. The first test version was finished in 1955, and the first real site began operating in 1956. By 1959, it had completed thousands of practice interceptions of target drones from far away.

Sabre

The technology from the AN/FSQ-7 was also used to help create the SABRE airline reservation system.

In popular media

Parts of the AN/FSQ-7 were used as props in many movies and TV shows that needed old-looking computers, even though they were made in the 1950s. These included The Time Tunnel, The Towering Inferno, Logan's Run, WarGames, Independence Day, and the Planet of the Apes TV series.

Today

Today, you can see pieces of the AN/FSQ-7 at the Computer History Museum.

Equipment

MIT chose IBM to build the equipment for the AN/FSQ-7. The Central Computer System included two computers for backup, each with parts like memory and control systems. The Q7 had many input and output devices, such as card readers, printers, and special consoles for showing radar information.

The AN/FSQ-7 used core memory to store data, with each piece of information being a 32-bit word. It had two sets of memory banks, one larger and one smaller, to help manage all the data needed for air defense.