How the SAGE Development Began

Events leading to the adoption of voice telephone lines for air-defense operational messages are described. This process paved the way for the use of operational data lines in the SAGE (Semi-Automatic Ground Environment) system. The paper describes the early considerations leading to the use of a digital computer in SAGE, and how Whirlwind was chosen to be that computer. The context of the development of magnetic core memory is illuminated. The attitudes of engineering professionals toward digital equipment are reviewed. The author reveals how the name "Ground Environment" was created.