Robotics Reference
In-Depth Information
1,000 words.
14
A proper machine using telephone relays would
have needed 40,000 relays and filled a whole room.
The basic principle was that a small pin could be positioned right or
left of a steel lug, thus memorizing the value 0 or 1. This was some-
thing new on the Babbage designs. It was clear that programs could
be stored provided they were composed of bit combinations—one
reason why programmable memory had already been patented by
1936. [5]
One of Zuse's friends helping with the project was Helmut Schreyer
who, at that time, was working on the development of electronic relays.
Schreyer had the bright idea of using vacuum tubes (or valves as they
are called in the U.K.). At first Zuse thought the idea to be a joke, as
Schreyer was full of fun and given to fooling around. But after thinking
about the suggestion Zuse decided that the idea was definitely worth a
try. Thanks to a discipline called
switching algebra
(i.e., Boolean algebra
translated into electrical switching), Zuse had already married together
two different types of technology—mechanics and electromagnetics. But
vacuum tubes could switch a million times faster than mechanical and
electro-magnetic components, so Zuse realised that with vacuum tubes
the possibilities were staggering.
Zuse was working on a completely private basis, with no government
or corporate support but just the help of some friends, and it took him
two years to develop a semi-functioning electro-mechanical computer.
ployed thin metal plates for its memory that had 64 cells each of 22
bits. The machine itself proved somewhat unreliable but, by employ-
ing switching algebra, it proved easy for Zuse to develop a relay-based
version.
Zuse's Z2 computer employed the same type of mechanical mem-
ory as the Z1, but Zuse used old relays that he obtained from telephone
companies to construct the arithmetic and control units. Subsequently
he also built his Z3 computer completely out of relays, 600 of which
were used for the arithmetic unit and 1,800 for the memory and control
units. A page from Konrad Zuse's diary recalls that on 12 May 1941 he
presented the working Z3 to scientists in Berlin. It is now undisputed
that the Z3 was the first reliable, freely programmable, working com-
14
Zuse's use of “word” refers to the unit of storage in a computer.
