SWAC (computer)
Encyclopedia
The SWAC was an early electronic digital computer
built in 1950 by the U.S.
National Bureau of Standards
(NBS) in Los Angeles, California. It was designed by Harry Huskey
. Like the SEAC
, 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
).
The machine used 2,300 vacuum tube
s. It had 256 words of memory
, using Williams tube
s, with each word being 37 bit
s. It had only seven basic operations: add, subtract, and multiply (single precision and double precision
versions); comparison, data extraction, input, and output.
When the SWAC was completed in July 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 similar multiplication took 384 microseconds. It was used by the NBS until 1954 until the Los Angeles office was closed, and then by UCLA until 1967 (with modifications). It was charged out there for $40 per hour.
In 1952, Raphael M. Robinson
used the SWAC to discover five Mersenne prime
s—the largest prime numbers known at the time, with 157, 183, 386, 664, and 687 digits.
Computer
A computer is a programmable machine designed to sequentially and automatically carry out a sequence of arithmetic or logical operations. The particular sequence of operations can be changed readily, allowing the computer to solve more than one kind of problem...
built in 1950 by the U.S.
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
National Bureau of Standards
National Institute of Standards and Technology
The National Institute of Standards and Technology , known between 1901 and 1988 as the National Bureau of Standards , is a measurement standards laboratory, otherwise known as a National Metrological Institute , which is a non-regulatory agency of the United States Department of Commerce...
(NBS) in Los Angeles, California. It was designed by Harry Huskey
Harry Huskey
Harry Douglas Huskey is an American computer designer pioneer.Huskey was born in the Smoky Mountains region of North Carolina and grew up in Idaho. He gained his Master's and then his PhD in 1943 from the Ohio State University on Contributions to the Problem of Geocze...
. Like the SEAC
SEAC (computer)
SEAC was a first-generation electronic computer, built in 1950 by the U.S. National Bureau of Standards and was initially called the National Bureau of Standards Interim Computer, because it was a small-scale computer designed to be built quickly and put into operation while the NBS waited for...
, 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
RAYDAC
The RAYDAC was a one-of-a-kind computer built by Raytheon. It was started in 1949 and finished in 1953. It was installed at the Naval Air Missile Test Center at Point Mugu, California....
by Raytheon
Raytheon
Raytheon Company is a major American defense contractor and industrial corporation with core manufacturing concentrations in weapons and military and commercial electronics. It was previously involved in corporate and special-mission aircraft until early 2007...
).
The machine used 2,300 vacuum tube
Vacuum tube
In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s. It had 256 words of memory
Computer storage
Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is one of the core functions and fundamental components of computers....
, using Williams tube
Williams tube
The Williams tube or the Williams-Kilburn tube , developed in about 1946 or 1947, was a cathode ray tube used to electronically store binary data....
s, with each word being 37 bit
Bit
A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...
s. It had only seven basic operations: add, subtract, and multiply (single precision and double precision
Double precision
In computing, double precision is a computer number format that occupies two adjacent storage locations in computer memory. A double-precision number, sometimes simply called a double, may be defined to be an integer, fixed point, or floating point .Modern computers with 32-bit storage locations...
versions); comparison, data extraction, input, and output.
When the SWAC was completed in July 1950, it was the fastest computer in the world. It continued to hold that status until the IAS computer
IAS machine
The IAS machine was the first electronic computer built by the Institute for Advanced Study , in Princeton, New Jersey, USA. It is sometimes called the von Neuman machine, since the paper describing its design was edited by John von Neumann, a mathematics professor at both Princeton University...
was completed a year later. It could add two numbers and store the result in 64 microseconds. A similar multiplication took 384 microseconds. It was used by the NBS until 1954 until the Los Angeles office was closed, and then by UCLA until 1967 (with modifications). It was charged out there for $40 per hour.
In 1952, Raphael M. Robinson
Raphael M. Robinson
Raphael Mitchel Robinson was an American mathematician.Born in National City, California, Robinson was the youngest of four children of a lawyer and a teacher. He was awarded the BA , MA , and Ph.D. , all in mathematics, and all from the University of California, Berkeley. His Ph.D...
used the SWAC to discover five Mersenne prime
Mersenne prime
In mathematics, a Mersenne number, named after Marin Mersenne , is a positive integer that is one less than a power of two: M_p=2^p-1.\,...
s—the largest prime numbers known at the time, with 157, 183, 386, 664, and 687 digits.
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 InstituteCharles Babbage InstituteThe Charles Babbage Institute is a research center at the University of Minnesota specializing in the history of information technology, particularly the history since 1935 of digital computing, programming/software, and computer networking....
, University of Minnesota. Forsythe discusses the career of her husband, George ForsytheGeorge ForsytheGeorge Elmer Forsythe was the founder and head of Stanford University's Computer Science Department. He served as professor and chairman of the department from 1965 until his death...
. At UCLA he became involved with the National Bureau of Standards Western Automatic Computer (SWAC) until 1957, when the National Bureau of Standards closed its operation at UCLA. Also discusses his founding of the Stanford Computer Science Department. - Margaret R. Fox Papers, 1935-1976, Charles Babbage InstituteCharles Babbage InstituteThe Charles Babbage Institute is a research center at the University of Minnesota specializing in the history of information technology, particularly the history since 1935 of digital computing, programming/software, and computer networking....
, 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.