(MAD) An early programming language, based on IAL, developed at the University of Michigan by R. Graham, Bruce Arden, and Bernard Galler in 1959. MAD was one of the first extensible languages: the user could define his own operators and data types. MAD ran on the IBM 704, IBM 709 and IBM 7090. It was ported to the IBM 7040 at the City College of New York by Robert Teitel and also to Philco, Univac and CDC computers. Mad/1 was a later version.