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LEO I, the First Stored-Program Computer to Run Business Programs on a Routine Basis

11/17/1951
The LEO I main control panel. Circa 1951.

The LEO I main control panel. Circa 1951.

On November 17, 1951 LEO I (Lyons Electronic Office) ran a program to "evaluate costs, prices and margins of that week's baked output" at tea shop operator J. Lyons and Company in England. The LEO adaptation of the EDSAC was the first stored-program electronic computer to run business programs on a routine basis. “LEO’s early success owed less to its hardware than to its highly innovative systems-oriented approach to programming, devised and led by David Caminer.”

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