1940 to 1949: Computing During World War II and the Postwar Era - The Technical and Social History of Software Engineering - page 73

Postwar Computer Development
Two of the more technically important postwar computers were developed at Vict-
oria University in Manchester, England. The first was the Manchester Mark I, also
called the Small-Scale Experimental Machine (SSEM), which was operational in
1948.
The second and larger computer was the Manchester Automatic Digital
Machine (MADM), which was operational in 1949. The British press called this
machine an “electronic brain,” and this started a dispute between the engineering
side of the university and the medical school. The dispute centered on whether
computers could ever be creative.
The MADM led to 34 patents, some of which were later used in the IBM 701
and IBM 702 computers. The designers of the MADM were Frederic Williams and
Tom Kilburn.
Kilburn and Williams filed a patent for a special kind of cathode ray tube called
the Williams-Kilburn tube. It provided one of the first and fastest memory devices
for storing digital data. Some of the early computers that used Williams-Kilburn
tubes included the IBM 701 and IBM 702, the Univac Whirlwind, and the Ferranti
Mark I.
When a dot is drawn on a cathode ray tube, it results in a positive charge, and
the area surrounding the dot becomes negative. The charges spontaneously dis-
perse, but they can be read and manipulated to store data. These tubes permitted
random access, which was a major advance that opened up new kinds of compu-
tation.
Williams-Kilburn tubes were somewhat troublesome and not fully reliable.
They were used during the late 1940s but were soon replaced by magnetic core
memory devices in the early 1950s. Magnetic core memory was faster and more
reliable.
However, when first introduced, magnetic cores had to be assembled by hand,
using retrained garment workers who could deal with very small objects. In the
early years of core memory, hundreds of garment workers in Europe and the Un-
ited States were retrained to build computer core memories. As it happens, auto-
mated equipment for garment making occurred at about the same time, so other-
wise the garment workers might have been laid off or unemployed.
Later in 1964, Dr. Robert Dennard of IBM's Thomas J. Watson Research
Center would receive U.S. patent 3,387,286 for the invention of DRAM, which