The Systems Development Corporation started as part of RAND, in 1955, to develop software for the national defensive radar system known as SAGE (Semi-Automatic Ground Environment), which linked remote radar sites with information processing and routing nodes. SAGE was the first nationwide real-time computing system, and worked as a kind of continental central nervous system, alerting the military of incoming threats, hopefully within time to coordinate a response. The Systems Development Corporation grew quickly, doing more informational infrastructure systems and time-sharing computer work for defense contractors, building a headquarters at 2500 Colorado Boulevard in Santa Monica, where it employed 3,000 people. It was bought by the Burroughs Corporation in 1981 (which merged with Sperry a few years later, which became Unisys; then it was renamed Paramax, and was sold to Loral, which sold it to Lockheed, and is now part of L3Harris). With operations relocated, the headquarters building was torn down and replaced with a new office park called the Water Garden in the 1990s, in the heart of “Silicon Beach.”