Magnetic Drum Digital Differential Analyzer

The MADDIDA (MAgnetic Drum DIgital Differential Analyzer) was a special-purpose digital computer used for solving systems of ordinary differential equations. It was the first computer to represent bits using voltage levels and whose entire logic was specified in Boolean algebra. Invented by Floyd Steele, MADIDDA was developed at Northrop Aircraft Corporation between 1946-49 to be used as a guidance system for the Snark missile. No guidance system, however, resulted from the work on the MADDIDA, and rather it was used for aeronautical research In 1952, the MADDIDA became the world's top-selling commercial digital computer (albeit a special-purpose machine), six units having been sold. (The general-purpose UNIVAC I delivered its seventh unit in 1954.)