Randell was employed at English Electric from 1957 to 1964 where he was working on compilers. His work on ALGOL 60 is particularly well known, including the development of the compiler for the English Electric KDF9, an early stack machine. In 1964, he joined IBM, where he worked at the Thomas J. Watson Research Center on high performance computer architectures and also on operating system design methodology. In May 1969, he became a Professor of Computing Science at the then named University of Newcastle upon Tyne, where he has worked since then in the area of software fault tolerance and dependability.