Considers various pioneers and their contribution to
the Computing history.
Their Concepts and Theories.
How they became the basis of Computing.
Turing Test in AI
Boolean Algebra and Switching Circuits
Von Neumann Architecture.
Nineteenth century mathematician,
His calculus of logic is known as Boolean
Introduced two quantities “0” and “1”.
He then employed symbols such as x, y, z,
etc., to represent collections or Classes.
Introduced three operators (+ , - , x).
These symbols obeyed a rich collection of
algebraic laws such as Additive Identity,
Associativity, Commutativity and etc.
Foundation of all modern computers.
Consists of propositions that are either true or false.
Variables (e.g., A, B, etc.) are used to stand for
Propositions must be either true or false.
E.g. 2 + 2 = 4 is true.
2 ∗ 5 = 11 is false.
Propositions may be combined using logical connectives to
form new propositions.
The standard logical connectives are…
AND - ∧
OR - ∨
NOT - ￢
These connectives may be expressed using the other
E.g. A ⇒ B is equivalent to ￢A∨B
E.g. A ⇔ B is equivalent to (A ⇒ B) ∧ (B ⇒ A)
AND, OR and NOT Gates
Boolean logical operations are implemented by
electronic AND, OR and NOT gates.
Fundamental building blocks for more complex
Charles Babbage is considered to be one of the fathers
He was interested in a method that calculation could
be done mechanically.
Introduced a design concept for Difference Engine and
Built in 1853.
Compute polynomials of degree 4 on 15-digit numbers.
Compute and print mathematical tables mechanically.
The only operation that the Difference Engine can
perform is the addition.
Finite differences was the concept of calculating the
A key weakness is that it requires the intervention of
humans to perform the calculation.
Difference Engine is on display in the Science Museum
in London. 10
Babbage proposed a revolutionary idea for analytic
engine to resolve weaknesses of difference engine.
Built in 1978.
Included a processor, memory.
Way to input information and output results.
Capable of executing all possible tasks that may be
expressed in algebraic notation.
Used punched cards to store programs to perform the
analysis and computation in the Analytic Engine.
Punched cards in the design was extremely powerful.
Operation cards are used to define the operations.
Variable cards define the variables.
Ada Lovelace suggested to a method write a program
in Analytic Engine.
Over 100 years before Von Neumann’s architecture.
Formalism was proposed by David Hilbert.
This formal system is the basis of modern predicate
A formal system consists of a formal language.
Included axioms, definitions, universal and existential
quantification, and formalization of proof.
Determines the truth or falsity of any mathematical
statement based on a Algorithm with set of rules.
E.g.1 x = y;
this returns true if x is the same as y, and false
E.g.2 More complex expression such as
f (x, y, z) = w is true
if f (x, y, z) is identical with w, and false otherwise.
E.g.3 P(x) returns true if x is prime. where P() is
termed a concept.
“P(5) = true”
Was a British mathematician who was highly influential
in the development of Computer Science.
Engaged in the Design work in the development of first
stored program computer.(ACE)
Introduced the concept of Turing machine.
Designed a electromechanical machine known has
bombe to break in to Enigma Codes.
Turing machine is very simple machine.
Equivalent to an actual physical Computer.
The machine may read from and write to the tape.
Has an associated set of rules that defines its behavior.
Programmed to solve any problem for which there is
It was used to determine the solvability of certain
Turing devised a famous
experiment that would allow a
computer to be judged as a
conscious and thinking machine.
The concept of this Turing test
was the foundation of Artificial
Shannon found that Boolean algebra could be
employed to simplify the design of circuits and
telephone routing switches.
He laid the foundation of modern Information Theory.
Shannon proposed the idea of converting any kind of
data to binary digits.
Boolean Algebra & Switching Circuits
Switching circuit “Xab” between two terminals a and b
Xab = 0 if open
Xab = 1 if closed
Sending information rapidly and reliably from the
source point to the destination point without any
Secure way of communication between two parties.
Messages are encrypted according to a Mathematical
John von Neumann
Made fundamental contributions to a vast number of
fields including computer science.
His work on Quantum Mechanics was very influential.
He introduced an Architecture during his work on
ENIAC & EDVAC.
Von Neumann Architecture
The early machines could perform only a particular
This architecture uses a single store for both machine
instructions and programs.
Much simpler to reconfigure the computer for a
Was a German Engineer.
Pioneered in building first functional tape stored,
program-controlled computer.( Z3)
He designed the first high-level programming
Considered the contributions of important people in
the history of computing including Boole, Babbage,
Shannon, Turing and von Neumann.
Boole was an English mathematician who developed
Boolean Algebra which is the foundation of all modern
Charles Babbage did pioneering work on the
Difference Engine and Analytic Engine.
Turing is famous for his work on a theoretical
mathematical machine termed the “Turing Machine”.
He also made contributions to the cryptography and to
Claude Shannon was the first person to see the
applicability of Boolean Algebra to simplify the design
of circuits and telephone routing switches.
Von Neumann was a mathematician gave his name to
the Von Neumann architecture that is used in almost
Zuse was a German engineer who developed the Z3
machine in 1941. He also developed the Plankalkul
high-level programming language in 1946.
A Brief History of Computing by Gerard O’Regan.