Semi-Automatic Ground Environment

The Semi-Automatic Ground Environment, known as SAGE, was a system of large computers and associated networking equipment that coordinated data from many radar sites into a single unified image of the airspace over a wide area, directing and controlling the North American Aerospace Defense Command's response to a possible Soviet air attack from the late 1950s into the 1980s. Its computers, the IBM-built AN/FSQ-7 Combat Direction Central, were described as the largest discrete-component computers ever built, with dozens produced for direction centers across North America, each occupying an entire floor of a building. Operators tracked targets automatically developed from radar data and issued commands through light guns and teleprinters to interceptor aircraft and missile defenses.