GM-NAA I/O

The GM-NAA I/O (from General Motors and North American Aviation input/output system) is the first operating system in the history of computing.

It was created in 1956 by Robert L. Patrick of General Motors and Owen Mock of North American Aviation for an IBM 704 computer. The basis of its construction was the monitor system created in 1955 by programmers of General Motors for their IBM 701.

GM-NAA I/O, whose primary function was to automatically run a new program once the current one was finished, was made up of program-accessible routines that provided common access to input/output devices.