The SWAC ( Standards Western Automatic Computer ) 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 .
7-734: 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 ). The machine used 2,300 vacuum tubes . It had 256 words of memory , using Williams tubes , with each word being 37 bits . It had only seven basic operations: add, subtract, and fixed-point multiply; comparison, data extraction, input and output. Several years later, drum memory
14-626: The Nobel Prize in Chemistry in 1964. SEAC (computer) SEAC ( S tandards E astern A utomatic C omputer or S tandards E lectronic A utomatic C omputer ) was a first-generation electronic computer , built in 1950 by the U.S. National Bureau of Standards (NBS) 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
21-678: The NBS waited for more powerful computers to be completed (the DYSEAC ). The team that developed SEAC was organized by Samuel N. Alexander . SEAC was demonstrated in April 1950 and was dedicated in June 1950; it is claimed to be the first fully operational stored-program electronic computer in the US. Based on EDVAC , SEAC used only 747 vacuum tubes (a small number for the time) eventually expanded to 1,500 tubes. It had 10,500 germanium diodes which performed all of
28-456: The logic functions (see the article diode–transistor logic for the working principles of diode logic), later expanded to 16,000 diodes. It was the first computer to do most of its logic with solid-state devices. The tubes were used for amplification, inversion and storing information in dynamic flip-flops . The machine used 64 acoustic delay lines to store 512 words of memory , with each word being 45 bits in size. The clock rate
35-578: 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 similar multiplication took 384 microseconds. It was used by the NBS until 1954 when the Los Angeles office was closed, and then by UCLA until 1967 (with modifications). It
42-563: Was charged out there for $ 40 per hour. In January 1952, Raphael M. Robinson used the SWAC to discover five Mersenne primes —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 done by Dorothy Hodgkin . This was fundamental in Hodgkin receiving
49-489: Was kept low (1 MHz ). The computer's instruction set consisted of only 11 types of instructions: fixed-point addition, subtraction, multiplication, and division; comparison, and input & output. It eventually expanded to 16 instructions. The addition time was 864 microseconds and the multiplication time was 2,980 microseconds (i.e. close to 3 milliseconds). Weight: 3,000 pounds (1.5 short tons; 1.4 t) (central machine). On some occasions SEAC
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