University of Michigan Executive System

The University of Michigan Executive System, usually called UMES, was a batch operating system developed at the University of Michigan in 1958 and widely used at many universities. It was based on the General Motors Executive System for the IBM 701 and was revised to run on the mainframes then in use at Michigan, the IBM 704, 709 and 7090, and to handle better the small student jobs that were expected to be the main workload at a university. The system offered the FORTRAN and MAD programming languages. UMES stayed in use at the University of Michigan until 1967, when the Michigan Terminal System was phased in to take advantage of the virtual memory time-sharing hardware of the IBM System/360 Model 67. A three volume reference manual of about 1050 pages was published by the university Computing Center in September 1965.