University of Michigan Executive System

{{About|UMES, the computer operating system|the university|University of Maryland Eastern Shore}}

{{Use American English|date=February 2023}}

{{Use mdy dates|date=February 2023}}

{{Infobox OS

| name = University of Michigan Executive System (UMES)

| logo =

| screenshot =

| caption =

| developer = University of Michigan

| source_model =

| kernel_type =

| supported_platforms = IBM 704, IBM 709, IBM 7090

| ui =

| family =

| released = {{Start date and age|1958}}

| latest_release_version =

| latest_release_date =

| latest_test_version =

| latest_test_date =

| marketing_target =

| programmed_in = Assembly language

| prog_language = FORTRAN, MAD

| language = English

| updatemodel =

| package_manager =

| working_state = Discontinued

| license =

| preceded by = GM-NAA I/O

| succeeded by = Michigan Terminal System

| website =

}}

{{History of IBM mainframe operating systems|early}}

The University of Michigan Executive System, or UMES, a batch operating system developed at the University of Michigan in 1958, was widely used at many universities. Based on the General Motors Executive System for the IBM 701, UMES was revised to work on the mainframe computers in use at the University of Michigan during this time (IBM 704, 709, and 7090) and to work better for the small student jobs that were expected to be the primary work load at the university.

UMES was in use at the University of Michigan until 1967, when MTS was phased in to take advantage of the newer virtual memory time-sharing technology that became available on the IBM System/360 Model 67.