Resident monitor

A resident monitor was a piece of system software in many early computers from the 1950s to 1970s. It can be considered a primitive precursor to the operating system.[1]

On a general-use computer using punched card input the resident monitor governed the machine before and after each job control card was executed, loaded and interpreted each control card, and acted as a job sequencer for batch processing operations.[2]

Similar very primitive system software layers were typically in use in the early days of the later minicomputers and microcomputers before they gained the power to support full operating systems.[3]

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