Model V

The Model V was among the early[2] electromechanical[3] general purpose computers,[4][5][6] designed by George Stibitz and built by Bell Telephone Laboratories, operational in 1946.

Only two machines were built: first one was installed at National Advisory Committee for Aeronautics (NACA, later NASA), the second (1947) at the US Army’s Ballistic Research Laboratory (BRL).

[9] The tape-controlled (Harvard architecture)[4][10] machine had two (design allowed for a total of six) processors ("computers")[11] that could operate independently,[5][12][13] an early form of multiprocessing.

[9][15] Built and used internally by Bell Telephone Laboratories, operational in 1949.

Simplified version of the Model V (only one processor,[23] about half the relays) but with several improvements,[5][24][25] including one of the earliest use of the microcode.