The First National Air Defense Network
In the depths of the cold war, IBM was contracted to help safeguard the United States by building an air defense system known as the Semi-Automatic Ground Environment (SAGE).
When fully deployed in 1963, the system consisted of 27 centers throughout North America, each occupying an acre of floor space.
SAGE was the first large computer network to provide man-machine interaction in real time. It provided the user with speed, altitude, and weapons availability data.
Fortunately, while SAGE made available a number of formative computer technologies, much of its capabilities never had to be put into use.