Many famous scientists and engineers have been employed at Bell Labs. They have contributed to many branches of science: physics, chemistry, electronics, cognition, communications, computing, and even cosmology. Among the famous computer scientists who worked at Bell labs were Ed Moore, who contributed to automata theory, and Dick Hamming, who developed error-correcting codes. Unix was developed by a group of computer scientists including Brian Kernighan, Dennis Ritchie, and Ken Thompson. But perhaps the most remarkable scientist who ever worked at Bell Labs was Claude Shannon (1916–2001), who (besides his famous work on "Information Theory") proved that any digital function could be implemented using only two levels of elementary logic operations. Since this theory underlies modern digital design using electronic and-gates and orgates, Shannon could be called the father of digital design.