 This included working on many other computer technology advancements such as magnetic core memory, a large real-time operating system, an integrated video display, light guns, the first effective algebraic computer language, analog-to-digital and digital-to-analog conversion techniques, digital data transmission over telephone lines, duplexing, multiprocessing, and geographically distributed networks.IBM built fifty-six SAGE computers at the price of US$30 million each, and at the peak of the project devoted more than 7,000 employees (20% of its then workforce) to the project.SAGE had the largest computer footprint ever and continued in service until 1984.