Today, we meet the grandest computer of the early
1940s. The University of Houston's College of
Engineering presents this series about the machines
that make our civilization run, and the people
whose ingenuity created them.
We tend to view the computer
as having come into being only during the past 30
years. No doubt, it has come into its own during
that period. But serious attempts to do complicated
machine calculations were under way well before
The most important pre-war effort was started in
the 1920s by Vannevar Bush. It culminated in 1942
with the dedication of his huge Rockefeller
Differential Analyzer at MIT -- a one-hundred-ton
machine with 2000 vacuum tubes and 150 motors.
Bush's Analyzer was an analog computer. An analog
computer actually carries out an analogy of a real
physical process -- in this case, a mixed
electrical-mechanical analogy. A digital computer
is quite different. It breaks all computations down
into sequences of additions and subtractions and
solves equations by doing a lot of simple
Bush's computer quickly fell under the pall of
WW-II secrecy, but only after the head of
Electrical Engineering at MIT had proclaimed that
it would "mark the beginning of a new era in
mechanized calculus," and MIT president Compton had
announced that it would be "one of the great
scientific instruments of modern times."
When this wonderful device emerged from secrecy
five years later, it turned out that it'd slipped
into obsolescence. The new breed of high-speed
digital computers simply overtook it.
Historian Larry Owens looks at this fall from grace
and asks sadly, "How does one tell the story of a
machine?" Owens concludes that the real importance
of the fall is that it so clearly illustrates a
change in the very character of engineering after
the war. Bush, he observes, represented a kind of
engineering that was in contact with the workshop.
His computer was made up of complex mechanical and
electrical elements. It thought the way prewar
engineers thought -- in physical, graphical terms.
The modern digital computer, he points out, speaks
in a mathematical language to the more abstract and
mathematical breed of postwar engineers.
I'm John Lienhard, at the University of Houston,
where we're interested in the way inventive minds