Able to Store 2000 Words…WoW!

December 2, 1954:  IBM Delivers NORC to Navy

The most powerful computer, it could store 2000 words . . . WoW!!

Well the most powerful for its time. The Naval Ordnance Research Calculator (NORC) was built by IBM and delivered to the Naval Surface Weapons Center in Virginia.

The IBM Naval Ordnance Research Calculator (NORC) was a one-of-a-kind first-generation vacuum tube computer that went into service in December of 1954 and was likely the most powerful computer at the time. At the presentation ceremony, it calculated pi to 3089 digits, which was a record at the time. The calculation took only (only!) 13 minutes. How far we’ve come.

Assembling the NORC

It continued to be used until 1968. Its design influenced the IBM 701 and subsequent machines in the IBM 700 series of computers.

Wallace Eckert, Frank Diehl Fackenthal, Robert J. Oppenheimer, Thomas J. Watson, Sr., Columbia Vice President George Pegram (signing guest book), John von Neumann, and I.I. Rabi at the NORC reception at the Men’s Faculty Club, December 2, 1954. Photo courtesy Herb Grosch.

The machine originally used electrostatic tubes (CRT or Williams tube) for memory which stored 2000 words, with an access time of 8 microseconds. Each word consisted of 16 decimal digits, using four bits to represent each digit, plus two modulo-4 error-checking bits.

A word could store a 13-digit number with sign and 2-digit index, or one instruction. NORC used four sets of 66 electrostatic tubes in parallel for memory. Each of the tubes in a set of 66 stored one bit of each of 500 words, so each of the four sets of 66 tubes stored 500 words. An upgrade to the addressing circuitry for the Williams tubes allowed memory per tube to be expanded from 500 bits to 900 bits, expanding the total memory to 3600 words without needing to add any more Williams tubes.

At some point the Williams tube memory was replaced with 20,000 words of magnetic core memory, with an access time of 8 microseconds. With 1,300 vacuum tubes in the three systems of the computer, the NORC had a total of 9800 vacuum tubes and 10,000 crystal diodes.

This photo was published in IBM Business Machines, 23 December 1954; Byron Havens is on the right. The copy shown here is scanned from an original 8×10 glossy from IBM’s press kit.

The NORC had eight magnetic tape units which were similar to the tape drives on the IBM 701 system. The reels were 8 inch diameter and somewhat similar in appearance to a metal 16mm film reel. It had two printers that could print 150 lines per minute, although only one printer could be used at a time. It also had a card reader which could read 100 cards per minute, with four words stored per card.