1. An Illustrated
History of
Computation
Prof Bernie Cohen FBCS

2. Blue plaque on his mother's house
at 22 Ennismore Ave, Guildford

3. Computer science
is no more about computers than
astronomy is about telescopes.
Simplicity and elegance are unpopular
because they require hard work
and discipline to achieve
and education to be appreciated.
Edsger W. Dijkstra
1930 – 2002

4. The Magic Number ZERO
Introduced into Europe
by the Scythian friar
St Dyonisius Exiguus
(aka Dennis the Humble)
c. 470 – c. 544
who also introduced
BC and AD
into the calendar
and whose fomula for
calculating the date of Easter
was adopted by Pope Paul I.

5. The Problem of Easter
Victor 1, the first African Pope
(189-199), who broke with
the quatrodeciman Eastern
bishops because Rome fixed
Easter on a Sunday.
Passover Nisan 14
King Oswald of
Northumbria
convened the
Synod of
Whitby
to resolve the
The Celtic Church conflict
had its own
formula for Easter
William of Orange defeated James II
at the Battle of the Boyne

6. Computors
The Brunswiga
calculator
John Napier Blaise Pascal
1550 - 1617 1623 -1662
bones and his Pascaline
and
logarithms

7. Navigation, Longitude and Time
Charles
Babbage
(1791-1871)
" I wish to God these
calculations had been
executed by steam!"
Sir John
Herschel
(1792-1871)

8. The Difference Engine,
a special-purpose calculator designed to
tabulate logarithms and trigonometric
functions by evaluating finite differences to
create approximating polynomials.
The Analytical Engine, a Turing-complete,
general purpose computer.
As soon as an Analytical Engine exists, it will
necessarily guide the future course of the
science. Whenever any result is sought by its aid,
the question will then arise: ”By what course of
calculation can these results be arrived at by the
machine in the shortest time?"
Passages from the Life of a Philosopher, 1864

9. Augusta Ada Byron,
Countess Lovelace 1815- - 1852

10. Breaking the Codes at Bletchley Park
Enigma and the Bombe Lorenz and Colossus

11. The Theory of Computation
"On Computable Numbers,
with an Application to the
Entscheidungsproblem"
Proc LMS 1936
The Turing Machine,
The Halting Problem,
Artificial Intelligence
David Hilbert Alan Mathison Turing
1862 - 1943 1912 - 1954
John von Neuman speculated
about computers and the
Alonzo Church human brain in analogies
1903 - 1995 sufficiently wild to be worthy of
a medieval thinker,
λ-calculus and Alan Turing thought about
Recursion John von Neumann criteria to settle the question of
1903 - 1957 whether machines can think,
which we now know is about as
Stored-program Architecture relevant as the question of
Self-replicating Automata whether submarines can swim.
Game Theory E. W. Dijkstra

12. The man who built Colossus
Tommy Flowers
1905 - 1998
When you leave valves switched on,
they don't burn out.
I can't tell you how to do it ,
but I wouldn't do it like that.
ca. 1966

13. More British Pioneers
William Shockley, Bell Labs,
inventor of the junction
transistor (1951),
the man who brought silicon
to Silicon Valley
born London 1910
Freddie Williams, U. of Manchester,
inventor (with Tom Kilburn) of the
Ernest Kaye, died April 21, 2012,
Williams Tube, the first electronic
last surviving member of the team
storage device, used in the
that built the Lyons Electronic Office,
Ferranti Mark 1, 1951...
1951, the world's first business
computer.
… the world's first
commercially available
electronic computer, built
by a team includng
Maurice Wilkes,
Christopher Strachey and
Tim Berners-Lee's parents.

14. Self-Defeating Technology
The Blundell Vector Slide Rule
(1952)
and High Speed Electronic
Circuits
VLSI
(Very Large Scale
Integration)
and the
Swiss Watch Industry

15. Computers in Business
The Elliott 153, Borehamwood, 1954
At present four Government offices have been equipped with computers
and orders have been placed for equipment for a further four.
Studies of the possible use of computers in five more offices
have almost been completed.
Jocelyn Simon, Financial Secretary to the Treasury,
House of Commons debate, June 26, 1958

16. Programming Languages
Tom Kilburn's
Highest Common Factor
routine, the first program run
on the'Baby', predecessor of
the Machester Mark 1 and
Ferranti Mark 1, 1948.

17. Programming Languages
Coding in
English???
'DIVIDE CAKE
INTO THREE”
The use of COBOL
cripples the mind;
its teaching should,
therefore,
be regarded as
a criminal offence.
E. W. Dijkstra
Grace Murray Hopper, John W Backus, Peter Naur,
USN, 1906 - 1992 IBM, 1924 - 2007 U Copenhagen,
First compiler 1951 FORTRAN 1954 1928 -
COBOL 1959 BNF : Backus-Naur (or Backus Normal) Form
syntactic metalanguage in which the grammar
of Algol 60 was fomally defined.
Panini (ca. 550BC) constructed a formal grammar of Sanskrit, the Ashtadhyayi

18. Programming Languages
BASIC, Darmouth College, NH, 1964
John G. Kemeny Thomas E. Kurtz
1926 -1992 1928 -
Manhattan Project with
John von Neumann.
Princeton PhD (Type
Theory vs Set Theory)
under Alonzo Church.
Mathematical assistant
to Einstein.
President of
Dartmouth College.
Chair of Three MIle
Island commission
It is practically impossible to teach good programming style
to students that have had prior exposure to BASIC;
as potential programmers they are mentally mutilated
beyond hope of regeneration.
E. W. Dijkstra

19. More Programming Languages
Christopher Strachey 1916 - 1975
Scion of the Bloomsbury Group
Designed Programming languages for Elliott and Ferranti.
Creator of CPL, 'Christopher's Programming Language',
from which came BCPL, then B, then C, then Unix.
First Prof of Computer Science at Oxford,
founded denotational semantics,
the formal theory of programming languages.
John McCarthy 1927 -2011
Developed LISP at MIT in 1958:
a Turing-complete language with a few simple
operators and a notation for functions,
which provided the foundation for
Artificial Intelligence.

20. Formal Specification & Verification
Formal syntax of a programming language defines
all valid programs in a finite collection of
recursive production rules.
A programming language compiler generates
executable code for each construct
defined by a production rule.
Formal semantics of a programming language defines
the meaning of each construct as a logical relation
between the states of the computation
before and after its execution.
Formal specification of a program is a logical relation
that its execution should guarantee
Robin Milner, 1934 - 2010 betweeen its input and its output.
Ferranti, Cambridge,
Edinburgh, Stanford, etc. Verification of a program is the proof
Automatic theorem proving that its semantics satisfies it specification.
ML, CCS, LCF,
Many safety-critical systems are now
pi-calculus.
required to be formally verified.

21. Recursion and Invariance
Dijkstra's Ball Game The Mutilated Chessboard

22. Recursion and Induction:
Proving that 1 + 1 = 2
The Theory NAT Define
Signature '0' as z
z: NAT '1' as s z
s: NAT → NAT '2' as s s z
p : NAT, NAT → NAT '+' as p
Axioms
p(z, n) = n .....................1 Proof
p(s m, n) = s p(m, n)......2 '1 + 1'
= p(s z, s z) by definition
= s p(z, s z) by axiom 2
=ssz by axiom 1
= '2' by definition

23. Minis and Mainframes
The DEC PDP 8, 1965
up to 32K 12-bit words.
666KHz
The IBM 360, 1964
Up to 8Mb 32-bit words
1Mhz

24. Remote Batch Terminals
Televideo 925, 1982
The sad tale of the sheriff
and the IBM sales engineer

25. The Single Chip Microprocessor
Intel 4004. 1970 Intel 8008, 1971
4kB in 4-bit words 16Kb in 8-bit words
2300 transistors 3500 transistors
740KHz 800KHz
$200 $120

26. Personal Computers
Homebrew Computer Club, Silicon Valley
The MITS Altair 8800, 1975
$400 kits for electronics hobbyists.
10,000 kits shipped
No software
Microsoft founded to supply a BASIC interpreter.
CP/M OS added later.
Processor Technology Sol-20, 1977
'IBM Blue' case and walnut sides
Video and tape I/O interface boards
built-in.
Designed by Lee Felsenstein.
Kansas City data transfer standard.

27. The 1977 Trinity
Commodore PET
Chuck Peddle TRS-80
Apple II Radio Shack
Steve Wozniak
and Steve Jobs

28. Xerox PARC
The Xerox 914 copier, 1959, generated so
much profit that, in 1970, Xerox founded a
non-profit research lab in Palo Alto with
instructions not to make product.
The Xerox Alto, 1973
A personal computer with
mouse, graphical user interface and ethernet.
Inspired Steve Jobs to design the Apple Mac.
The Xerox 8010 Star (or Dandelion), 1981
$16,595
Powered by a Symbolics LISP chip.
Rejected as a product line by Xerox.

29. Personal Computers
Atari 400, 1979
The original games machine The IBM PC, 1981
4 million sold 4.77MHz Intel 8088, up to 256Kb RAM
IBM thought of buying the 2 floppy disk drives, open architecture
company to get it, but instead Operating system MS-DOS by Microsoft
designed ... based on QDOS, based on CP/M
$1565

30. Home Computers
Commodore 64, 1982
17 million sold BBC Model A/B, 1981
Acorn (ARM)
Millions sold
Amstrad CPC464, 1984
Sinclair ZX Spectrum, 1982 3 million sold
5 million sold (not including clones)

31. WIMP
Windows, Icons, Mice and Pointers
Apple Macintosh, 1984 8MHz Widows 1.0 1985,
Motorola 68000 2 years late, slow and buggy
MacPaint, MacWrite, Mac Draw Windows 2.0 1987
128k, $2495 Mac look-alike,
256k, $2795 Aldus Pagemaker, Excel, Word,
Corel Draw

32. Meanwhile … on the telephone
Alexander Almon Brown
Graham Bell Strowger
1847 - 1922 1839 - 1902
Prof of Elocution Undertaker
Telephony, First exchange
aeronautics, La Porte, IN, 1892
hydrofoil and 75 subsribers
many other First UK autopmatic
inventions. exchange
Bell Labs. Epsom, 1912
In 1876, the President of
Western Electric declined to
buy Bell's patent for
$100,000, claiming that the
telephone was just a toy.
Two years later, he offered
$2,000,000 for it.

33. Stored Program Controlled
Telephone Switching
First in Europe
10CX, 1967
ITT BTM
Wilrijk, Belgium
First digital exchange
in world
Moorgate PCM, 1971
London
First in world ITT STC
No. 1 ESS, 1965
AT&T Western Electric
Succasunna, NJ

34. Convergence with Telecoms
Alec Reeves Vint Cerf Martin Cooper
Pulse code TCP/IP on Motorola DynaTac ('The Brick')
modulation. 1937 Arpanet, 1972 1973
Tim Berners-Lee Apple
Hypertext, 1980 iPad 4s
plus Internet 2012
= WWW, 1989

36. Ubiquitous Computing
Moses, meet Steve.
He's going to upgrade your tablet.