The AN/USQ-20, or CP-642 or

Naval Tactical Data System Naval Tactical Data System (NTDS) was a computerized information processing system developed by the United States Navy in the 1950s and first deployed in the early 1960s for use in combat ships. It took reports from multiple sensors on different sh ...

(NTDS), was designed as a more reliable replacement for the Seymour Cray-designed

AN/USQ-17 The AN/USQ-17 or Naval Tactical Data System (NTDS) computer referred to in Sperry Rand documents as the Univac M-460, was Seymour Cray's last design for UNIVAC. UNIVAC later released a commercial version, the UNIVAC 490 and that system was later u ...

with the same

instruction set In computer science, an instruction set architecture (ISA), also called computer architecture, is an abstract model of a computer. A device that executes instructions described by that ISA, such as a central processing unit (CPU), is called an ' ...

. The first batch of 17 computers were delivered to the Navy starting in early 1961. A version of the AN/USQ-20 for use by the other military services and

NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...

was designated the UNIVAC 1206. Another version, designated the G-40, replaced the vacuum tube

UNIVAC 1104 The UNIVAC 1103 or ERA 1103, a successor to the UNIVAC 1101, was a computer system designed by Engineering Research Associates and built by the Remington Rand corporation in October 1953. It was the first computer for which Seymour Cray was credi ...

in the

BOMARC Missile Program The Boeing CIM-10 BOMARC (Boeing Michigan Aeronautical Research Center) (IM-99 Weapon System prior to September 1962) was a supersonic ramjet powered long-range surface-to-air missile (SAM) used during the Cold War for the air defense of North ...

. The machine was the size and shape of an old-fashioned double-door

refrigerator A refrigerator, colloquially fridge, is a commercial and home appliance consisting of a thermally insulated compartment and a heat pump (mechanical, electronic or chemical) that transfers heat from its inside to its external environment so th ...

, about six feet tall (roughly 1.80 meters). Instructions were represented as 30-bit

word A word is a basic element of language that carries an semantics, objective or pragmatics, practical semantics, meaning, can be used on its own, and is uninterruptible. Despite the fact that language speakers often have an intuitive grasp of w ...

s in the following format: f 6 bits function code j 3 bits jump condition designator k 3 bits partial word designator b 3 bits which index register to use y 15 bits operand address in memory Numbers were represented as 30-bit words. This allowed for five 6-bit

alphanumeric Alphanumericals or alphanumeric characters are a combination of alphabetical and numerical characters. More specifically, they are the collection of Latin letters and Arabic digits. An alphanumeric code is an identifier made of alphanumeric ch ...

characters per word. The main memory was 32,768 words of

core memory Core or cores may refer to: Science and technology * Core (anatomy), everything except the appendages * Core (manufacturing), used in casting and molding * Core (optical fiber), the signal-carrying portion of an optical fiber * Core, the central ...

. The available

processor register A processor register is a quickly accessible location available to a computer's processor. Registers usually consist of a small amount of fast storage, although some registers have specific hardware functions, and may be read-only or write-only. ...

s were: *one 30-bit arithmetic (A) register. *a contiguous 30-bit Q register (total of 60 bits for the result of multiplication or the dividend in division). *seven 15-bit index (B) registers (note: register B0 is always zero).

References

External links

UNIVAC-NTDS: UNIVAC 1206, AN/USQ-20
– From the Antique Computer website {{DEFAULTSORT:AN USQ-20 UNIVAC hardware Transistorized computers Military computers Avionics computers Military electronics of the United States

See also

References

External links