System Development Corporation (SDC), based in Santa Monica, California, was considered the world's first computer software company.SDC started in 1955 as the systems engineering group for the SAGE air defense ground system at the RAND Corporation. RAND spun off the group in 1957 as a non-profit organization that provided expertise for the United States military in the design, integration, and testing of large, complex, computer-controlled systems.SDC became for-profit in 1969.