Today in 1956, the development of the Semi-Automatic Ground Environment (SAGE) was disclosed to the public.
SAGE collected and coordinated data from radar sites and processed it to produce a single unified image of the airspace over a wide area, directing the response of the North American Aerospace Defense Command (NORAD) to an air attack. SAGE’s use of telephone lines to communicate from computer to computer and computer to radar laid the groundwork for modems. The control program, the largest real-time computer program written at that time, spawned a new profession, software development engineers and programmers.
From MIT’s Lincoln Laboratory website:
Although the basic concept for SAGE was simple, the technological challenges were immense. One of the greatest immediate challenges was the need to develop a digital computer that could receive vast quantities of data from multiple radars and perform the real-time processing to produce targeting information for intercepting aircraft and missiles. Fortunately, and serendipitously, the initial concept development for such a computer was taking place on the MIT campus in the Servomechanisms Laboratory, under the direction of Jay Forrester. This effort, with its maturation under SAGE, laid the foundation for a revolution in digital computing, which subsequently had a profound impact on the modern world.