Robert Rex Seeber Jr.

Robert Rex Seeber Jr. was an American computing engineer best known as the chief architect of the IBM Selective Sequence Electronic Calculator (SSEC), the large hybrid of vacuum tubes and electromechanical relays that IBM built in New York in the late 1940s. He had worked in the Harvard group around Howard Aiken before IBM hired him away to design the company's own, more visible machine. Seeber designed the SSEC so that instructions could be treated as data, modified and stored under program control, and IBM filed a patent based on the machine in January 1949 that was later upheld as supporting its stored-program ability. Historians still usually classify the SSEC as the last of the programmable calculators rather than the first stored-program computer, which makes his design a landmark in a debated transition.