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KF5JRV > TECH 07.09.16 13:32l 48 Lines 2226 Bytes #999 (0) @ WW
BID : 1570_KF5JRV
Read: GUEST
Subj: SWAC Computer
Path: IW8PGT<CX2SA<N0KFQ<KF5JRV
Sent: 160907/1115Z 1570@KF5JRV.#NWAR.AR.USA.NA BPQK1.4.65
The SWAC was developed by the National Bureau of Standards Institute
for Numerical Analysis at the University of California at Los Angeles.
The SWAC concept was developed in October 1948 and the project was
started in January 1949. At one point it was called the ZEPHYR. It
began operation on August 17, 1950 and continued in service for 17
years, finally being retired in December 1967.
The SWAC differed from the NBS's other main computer the SEAC, in
that the SWAC operated in a parallel fashion rather than serially.
The SWAC used 37 CRTs (Williams-tube memory units). Magnetic Drum
storage was added in 1953. Some of those who worked on the SWAC
project and its later enhancements included:
Harry D. Huskey, H. Larson, R. Thorensen, M. Melankoff, D. Lehmer,
and others.
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.
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
multiply (single precision and double precision versions);
comparison, data extraction, input and output. Several years
later drum memory was added.
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 when 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 primes—the largest prime numbers known at the time,
with 157, 183, 386, 664 and 687 digits.
73, Scott kf5jrv
KF5JRV @ KF5JRV.#NWAR.AR.USA.NA
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