Naval Tactical Data System

Naval Tactical Data System (NTDS) refers to an information processing system developed by the United States Navy in the 1950s for use in combat ships.

Reason for development

Warships have rooms known as Combat Information Centers, or CICs. Until the advent of computers compact and robust enough to be used in ships at sea, collection and display of such information as the position of aircraft, ships, and submarines was done manually. NTDS was the United States Navy's first step in automating this information flow for use in attack or defense, to reduce the chance of error and to allow CICs to cope with a denser, faster-moving threat.

Hardware description

A variety of Univac embedded computers, typically with 30 bit words, 32K words of core memory, 16 parallel I/O channels (also 30 bits wide) connected to radars and other peripherals, and a RISC-like instruction set, were used. Logic circuits used discrete transistors and other elements soldered to a printed circuit board with connectors running along one side. Each card was coated in a varnish-like substance to prevent exposure to salt spray. A number of cards were connected and secured to a tray on rollers. In turn, several trays of various types, interconnected and secured to a metal enclosure, constituted the computer. Most NTDS computers were water-cooled, though some later lighter-weight models were air-cooled.

Seymour Cray and the NTDS

Although Seymour Cray is sometimes credited for developing the first NTDS processor, it was rejected by the Navy for reasons having to do with packaging and was replaced by a subsequent Univac design.