Robotics Reference
In-Depth Information
former mathematics teacher showed Zuse that calculations in Boolean
algebra are identical with the so-called propositional calculus of math-
ematical logic. This revelation encouraged Zuse to develop a system,
corresponding to Boolean algebra, of
conditional propositions
for relays.
(A conditional proposition is one of the form: “If this is true then that is
true”.)
It appears that Zuse's work with Boolean algebra predates that of
Claude Shannon by two or three years. Shannon's master's thesis, “A
Symbolic Analysis of Relay and Switching Circuits”, was written in 1936
and published in 1938, and it presented a method for representing any
circuit consisting of combinations of switches and relays by a set of
mathematical expressions. Shannon also developed a calculus for ma-
nipulating these expressions, his calculus being exactly analogous to the
calculus of propositions used in the field of symbolic logic. Shannon did
not know about Zuse's research in Nazi Germany—they were simply
researchers in different locations, independently developing the same
ideas at around the same time.
Along with Burack's much simpler machine, Zuse's work with re-
lays was the first creation of a working device that converted logic prob-
lems into a form in which they could be solved using electro-mechanical
means. Although Marquand had already designed a relay-based machine
in 1885, his drawings from that year were not published in his lifetime;
they lay in a collection of his papers in Princeton University library until
they were discovered by Alonzo Church in 1953. It is indicative of how
far ahead of their time the ideas of Peirce and Marquand were, that they
were suggested in 1877, drawn in 1885, but nothing similar was built
until Zuse's admittedly more sophisticated concept 50 years later.
Having solved the problem of how to handle logical deductions using
electro-mechanical relays, Zuse was faced with a different problem—a
form of high capacity computer memory was needed.
One device that could deal with this type of operation was the
electro-magnetic relay, which can adopt two positions, “open” or
“closed”. However, at the time I felt that the problem could be bet-
ter solved mechanically. I played around with all sorts of levers,
pins, steel plates, and so on, until I finally reached what was a
very useful solution, for those days. My device consisted mainly
of pins and steel plates, and in principle could be extended to
