IBM Naval Ordnance Research Calculator
| Company type | Computer system |
|---|---|
| Industry | Computing, Military technology |
| Founded | December 2, 1954 |
| Headquarters | United States |
| Products | First-generation vacuum tube computer |
The IBM Naval Ordnance Research Calculator (NORC) was a distinctive first-generation computer utilizing vacuum tube technology, constructed by IBM specifically for the United States Navy's Bureau of Ordnance. Commissioned in December 1954, it was arguably the most powerful computing machine available at that period. The system was created at the Watson Scientific Computing Laboratory under the leadership of Wallace Eckert and played a significant role in shaping the architecture of the IBM 701 and subsequent models within the IBM 700 series.
On December 2, 1954, NORC was officially delivered to the US Navy, achieving a remarkable feat by computing pi to 3,089 digits within just 13 minutes. In 1955, it was transferred to the Naval Proving Ground located in Dahlgren, Virginia, where it functioned as their principal computer until 1958 and continued operating until 1963.
Technology
Initially, NORC employed Williams–Kilburn tubes as its memory medium, capable of storing 2,000 words electrostatically with an access latency of 8 microseconds. Each word consisted of 16 decimal digits accompanied by error-detection bits and could represent either numerical data or instructions. The memory was divided into four groups of 66 tubes each, with every tube holding bits for 500 words; subsequent enhancements expanded this capacity to 3,600 words without adding more tubes.
Eventually, the Williams tube memory was superseded by a magnetic-core memory system containing 20,000 words while maintaining the same access time. NORC’s processing speed reached approximately 15,000 operations per second: addition required 15 microseconds, multiplication took 31 microseconds, and division consumed 227 microseconds. It also supported occasional execution of double precision calculations.
The hardware architecture included nearly 2,000 pluggable units featuring about 9,800 vacuum tubes and approximately 10,000 crystal diodes. Although there were sixty-two varieties of units utilized, just six types made up half of the circuitry, and eighteen types accounted for eighty percent.
NORC was equipped with eight magnetic tape drives similar to those used on the IBM 701 system; these had reels measuring eight inches in diameter. Unlike the IBM 701’s drives which had controls on an operator panel, NORC’s tape drive controls were positioned on top of the units. These drives operated at a data transfer rate of 71,500 characters per second. The system also contained two printers capable of outputting 150 lines per minute (though only one printer could be used simultaneously), a card reader processing 100 cards per minute with four words encoded per card, and a display unit combining a cathode-ray tube with a 35 mm film camera. This configuration captured images of the CRT screen onto film which was then developed for rear projection approximately twelve frames after exposure. For large volumes of data, text was also recorded onto film; personnel at the Naval Weapons Laboratory frequently examined these films in darkened environments to identify errors during critical computations.
Awards and honors
The asteroid designated 1625 The NORC, located within the main asteroid belt, was named by Paul Herget in tribute to this electronic calculator that significantly enhanced orbital computations for minor planets during its era.
Citations
External links
- Warner Pathé News coverage of the NORC: