Museum of Science, Boston, MA - IMG 3160

The SWAC (Standards Western Automatic Computer) was an early electronic digital computer built in 1950 by the

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National Bureau of Standards The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...

(NBS) in Los Angeles, California. It was designed by

Harry Huskey Harry Douglas Huskey (January 19, 1916 – April 9, 2017) was an American computer design pioneer. Early life and career Huskey was born in Whittier, in the Smoky Mountains region of North Carolina and grew up in Idaho. He received his bachel ...

Overview

Like the SEAC which was built about the same time, the SWAC was a small-scale interim computer designed to be built quickly and put into operation while the NBS waited for more powerful computers to be completed (in particular, the RAYDAC by

Raytheon Raytheon Technologies Corporation is an American multinational aerospace and defense conglomerate headquartered in Arlington, Virginia. It is one of the largest aerospace and defense manufacturers in the world by revenue and market capitali ...

). The machine used 2,300

vacuum tube A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied. The type known as a ...

s. It had 256 words of

memory Memory is the faculty of the mind by which data or information is encoded, stored, and retrieved when needed. It is the retention of information over time for the purpose of influencing future action. If past events could not be remembered, ...

, using

Williams tube The Williams tube, or the Williams–Kilburn tube named after inventors Freddie Williams and Tom Kilburn, is an early form of computer memory. It was the first random-access digital storage device, and was used successfully in several early co ...

s, with each word being 37

bit The bit is the most basic unit of information in computing and digital communications. The name is a portmanteau of binary digit. The bit represents a logical state with one of two possible values. These values are most commonly represented ...

s. It had only seven basic operations: add, subtract, and multiply (

single precision Single-precision floating-point format (sometimes called FP32 or float32) is a computer number format, usually occupying 32 bits in computer memory; it represents a wide dynamic range of numeric values by using a floating radix point. A floating ...

and

double precision Double-precision floating-point format (sometimes called FP64 or float64) is a floating-point number format, usually occupying 64 bits in computer memory; it represents a wide dynamic range of numeric values by using a floating radix point. F ...

versions); comparison, data extraction, input and output. Several years later,

drum memory Drum memory was a magnetic data storage device invented by Gustav Tauschek in 1932 in Austria. Drums were widely used in the 1950s and into the 1960s as computer memory. For many early computers, drum memory formed the main working memory o ...

was added. When the SWAC was completed in August 1950, it was the fastest computer in the world. It continued to hold that status until the IAS computer was completed a year later. It could add two numbers and store the result in 64

microseconds A microsecond is a unit of time in the International System of Units (SI) equal to one millionth (0.000001 or 10−6 or ) of a second. Its symbol is μs, sometimes simplified to us when Unicode is not available. A microsecond is equal to 1000 n ...

. A similar multiplication took 384 microseconds. It was used by the NBS until 1954 when the Los Angeles office was closed, and then by

UCLA The University of California, Los Angeles (UCLA) is a public land-grant research university in Los Angeles, California. UCLA's academic roots were established in 1881 as a teachers college then known as the southern branch of the California St ...

until 1967 (with modifications). It was charged out there for $40 per hour. In January 1952, Raphael M. Robinson used the SWAC to discover five

Mersenne prime In mathematics, a Mersenne prime is a prime number that is one less than a power of two. That is, it is a prime number of the form for some integer . They are named after Marin Mersenne, a French Minim friar, who studied them in the early 17 ...

s—the largest prime numbers known at the time, with 157, 183, 386, 664 and 687 digits. Additionally, the SWAC was vital in doing the intense calculation required for the X-ray analysis of the structure of

vitamin B12 Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. It is one of eight B vitamins. It is required by animals, which use it as a cofactor in DNA synthesis, in both fatty acid and amino acid metabolism. It ...

done by

Dorothy Hodgkin Dorothy Mary Crowfoot Hodgkin (née Crowfoot; 12 May 1910 – 29 July 1994) was a Nobel Prize-winning British chemist who advanced the technique of X-ray crystallography to determine the structure of biomolecules, which became essential for ...

.Hodgkin, D.C.; Pickworth, J.; Robertson, J.H; Trueblood, K.N.; Prosen, R.J; White, J.G. Nature. 1955. 176. 325. This was fundamental in Hodgkin receiving the

Nobel Prize in Chemistry ) , image = Nobel Prize.png , alt = A golden medallion with an embossed image of a bearded man facing left in profile. To the left of the man is the text "ALFR•" then "NOBEL", and on the right, the text (smaller) "NAT•" then "M ...

in 1964.

References

* Williams, Michael R. (1997). ''A History of Computing Technology''.

IEEE Computer Society The Institute of Electrical and Electronics Engineers (IEEE) is a 501(c)(3) professional association for electronic engineering and electrical engineering (and associated disciplines) with its corporate office in New York City and its operatio ...

. * **

External links

IEEE Transcript: SWAC—Standards Western Automatic Computer: The Pioneer Day Session at NCC July 1978

Oral history interview with Alexandra Forsythe

Charles Babbage Institute The IT History Society (ITHS) is an organization that supports the history and scholarship of information technology by encouraging, fostering, and facilitating archival and historical research. Formerly known as the Charles Babbage Foundation ...

, University of Minnesota. Alexandra Illmer Forsythe discusses the career of her husband,

George Forsythe George Elmer Forsythe (January 8, 1917 – April 9, 1972) was an American computer scientist and numerical analyst who founded and led Stanford University's Computer Science Department. Forsythe is often credited with coining the term "computer ...

. At

he became involved with the National Bureau of Standards Western Automatic Computer (SWAC) until 1957, when the

closed its operation at UCLA. Also discusses his founding of the Stanford Computer Science Department.
Margaret R. Fox Papers, 1935-1976

, University of Minnesota. collection contains reports, including the original report on the ENIAC, UNIVAC, and many early in-house National Bureau of Standards (NBS) activity reports; memoranda on and histories of SEAC, SWAC, and DYSEAC; programming instructions for the UNIVAC, LARC, and MIDAC; patent evaluations and disclosures relevant to computers; system descriptions; speeches and articles written by Margaret Fox's colleagues; and correspondence of Samuel Alexander, Margaret Fox, and Samuel Williams.
MERSENNE AND FERMAT NUMBERS
by RAPHAEL M. ROBINSON. February 7, 1954. From "The Prime Pages". {{commonscat, position=left, SWAC (computer) One-of-a-kind computers Vacuum tube computers National Institute of Standards and Technology 1950s computers Computer-related introductions in 1950 1950 in California Science and technology in Greater Los Angeles

Overview

See also

References

Further reading

External links