(b) Limited intercommunication between processing stages. (Later
computers had alterable instructions within the machine itself that directed the machine
to perform automatically.)
d. Aiken's Mark I Automatic Digital Computers, 1944.
Established technology and punch card techniques combined.
(2) Electromechanical: electromagnetic relays automatically controlled
internal operations, while 78 mechanical adding machines and desk calculators
performed arithmetic operations. The relays automated the calculating machines, so
that long calculations could be done without human intervention.
(3) Built-in programs or subroutines to handle logarithms and trigonometric
functions (in addition to capability for handling arithmetical operations).
1-26. THE ELECTRONIC PHASE (ELECTRONIC DIGITAL COMPUTERS)
a. Need for a Computer to Produce Trajectory Tables Generated by New
World War II Weapons Systems--ENIAC. Eckert and Mauchley (1939-1946).
First high-speed all electronic computer.
Tracked the path of new rockets and missiles.
(3) "Wire-your-own" instruction technique: not easily reprogrammed. For
each new problem, connections had to be redone.
very large: about the size of a silo (1800 square feet).
(5) Required over 17,000 vacuum tubes. If one vacuum tube went out, the
whole system went down. It also generated a lot of heat and had a short life-
(6) One thousand times faster than the previous generation of computers. It
could do 300 multiplications in one second, whereas the fastest electromechanical
devices could do only one per second.
b. The Stored Program Theory of Modern Computers.
(1) John Von Neuman spread the word about the concepts necessary for
devising modern stored program computers, though he didn't develop the ideas single-