He began in 1962 by writing a Fortran compiler for the PDP-4, before contributing to the development of the PDP-5 instruction set. Under Harlan Anderson (vice president of engineering), principal architect Gordon Bell led a team, including Kotok as an assistant logic designer, which developed the first commercial time-sharing computer, the PDP-6, designed and delivered in 1963–1964. Aiming at a scientific market, Digital machines had a 36-bit word length to accommodate artificial intelligence work in Lisp and to compete with IBM mainframe computers. In 1965, in what may have been the first around-the-world networking connection, a PDP-6 at the University of Western Australia in Perth was operated from Boston in the United States via a telex link.
