1930 to 1939: The Foundations of Digital Computing - The Technical and Social History of Software Engineering - page 39

offer equal pay and equal responsibilities, regardless of gender. IBM later did the
same for ethnic minorities who were often discriminated against. In future dec-
ades, the computer and software industries would be more egalitarian than some
of the older technical fields such as mechanical and electrical engineering. It is a
matter of sociological interest that computers and software started out with a ma-
jor company declaring equal rights and equal pay.
In 1936, Zuse started construction on a relay-based computer (similar to the
work of the American George Stibitz) called the Z1. This machine was finished in
1938 but proved to be unreliable for mechanical reasons. However, it did feature
programmability.
After an intermediate Z2 machine, later in 1941, Zuse finished a more sophist-
icated Z3 machine that was programmable, with the programs being entered via
punched film. Zuse's machines used binary numbers and are viewed as operating
precursors of today's computers. There is still some debate as to whether Zuse or
Atanasoff and Berry deserve credit for building the first working computer. In fact,
both worked independently, and both deserve credit.
In 1936, the famous Alan Turing published a seminal paper titled “On Comput-
able Numbers,” which is generally held to be a description of a working computer
with an executable program. Turing's work had both practical and theoretical con-
cepts that would lead to impressive future inventions and to working computers
used for code breaking.
A Turing machine is an abstract depiction of a working computer that sequen-
tially processes instructions and performs mathematical and logical operations.
Even today, a standard definition of a successful computer is that it be “Turing
complete” or embodies all of the concepts put forth in Turing's seminal paper.
Turing also developed and defined the concept of an algorithm , and he contrib-
uted important insights into problems that can be solved by a computer and prob-
lems that are insolvable. Turing's contributions to the war effort at Bletchley Park
will be discussed in the decade from 1940 to 1949.
In 1937, Claude Shannon, while a graduate student at MIT, wrote a thesis that
proved that electrical relays could implement the concepts of Boolean symbolic
logic. Shannon's work led to the development of successful digital circuitry, which
is needed for digital computers to operate.
A Russian investigator, Victor Shestakov from Moscow State University, de-
veloped a theory similar to Shannon's as early as 1935. However, the Shestakov
concepts were not published until 1941, so Shannon's ideas have precedence.