AN/USQ-20

The AN/USQ-20, or CP-642[1][2][3] or Naval Tactical Data System (NTDS), was designed as a more reliable replacement for the Seymour Cray-designed AN/USQ-17 with the same instruction set.

The first batch of 17 computers were delivered to the Navy starting in early 1961.

[4] A version of the AN/USQ-20 for use by the other military services and NASA was designated the UNIVAC 1206.

Another version, designated the G-40, replaced the vacuum tube UNIVAC 1104 in the BOMARC Missile Program.

The machine was the size and shape of an old-fashioned double-door refrigerator, about six feet tall (roughly 1.80 meters).