An Illustrated History of

ComputationProf Bernie Cohen FBCS

Blue plaque on his mother's houseat 22 Ennismore Ave, Guildford

Computer scienceis no more about computers than astronomy is about telescopes.

Simplicity and elegance are unpopular because they require hard work

and discipline to achieveand education to be appreciated.

Edsger W. Dijkstra1930 – 2002

The Magic Number ZERO

Introduced into Europeby the Scythian friar

St Dyonisius Exiguus(aka Dennis the Humble)

c. 470 – c. 544who also introduced

BC and ADinto the calendar

and whose fomula for calculating the date of Easter was adopted by Pope Paul I.

The Problem of Easter

Passover Nisan 14

Victor 1, the first African Pope(189-199), who broke with

the quatrodeciman Eastern bishops because Rome fixed

Easter on a Sunday.

The Celtic Church had its own

formula for Easter

King Oswald of Northumbria convened the

Synod of Whitby

to resolve the conflict

William of Orange defeated James IIat the Battle of the Boyne

Computors

John Napier 1550 - 1617

bonesand

logarithms

Blaise Pascal1623 -1662

and his Pascaline

The Brunswiga calculator

Navigation, Longitude and Time

" I wish to God these calculations had been executed by steam!"

Charles Babbage

(1791-1871)

Sir John Herschel

(1792-1871)

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

The Difference Engine,a special-purpose calculator designed to

tabulate logarithms and trigonometric functions by evaluating finite differences to

create approximating polynomials.

Augusta Ada Byron,Countess Lovelace 1815- - 1852

Enigma and the Bombe Lorenz and Colossus

Breaking the Codes at Bletchley Park

The Theory of Computation "On Computable Numbers,

with an Application to the Entscheidungsproblem"

Proc LMS 1936The Turing Machine,The Halting Problem,Artificial Intelligence

Alan Mathison Turing1912 - 1954

David Hilbert1862 - 1943

John von Neumann1903 - 1957

Alonzo Church1903 - 1995λ-calculusRecursion

Stored-program ArchitectureSelf-replicating Automata

Game Theory

John von Neuman speculated about computers and the human brain in analogies

sufficiently wild to be worthy of a medieval thinker,

and Alan Turing thought about criteria to settle the question of whether machines can think,

which we now know is about as relevant as the question of

whether submarines can swim.E. W. Dijkstra

Tommy Flowers1905 - 1998

The man who built Colossus

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

More British PioneersWilliam Shockley, Bell Labs,

inventor of the junction transistor (1951),

the man who brought siliconto Silicon Valley

born London 1910

Freddie Williams, U. of Manchester, inventor (with Tom Kilburn) of the Williams Tube, the first electronic

storage device, used in theFerranti Mark 1, 1951...

Ernest Kaye, died April 21, 2012,last surviving member of the team

that built the Lyons Electronic Office, 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.

VLSI (Very Large Scale

Integration)and the

Swiss Watch Industry

Self-Defeating Technology

The Blundell Vector Slide Rule (1952)

and High Speed Electronic Circuits

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

Computers in Business

Programming Languages

Tom Kilburn'sHighest Common Factor

routine, the first program run on the'Baby', predecessor of the Machester Mark 1 and

Ferranti Mark 1, 1948.

Programming Languages

Grace Murray Hopper, USN, 1906 - 1992First compiler 1951

COBOL 1959

John W Backus, IBM, 1924 - 2007

FORTRAN 1954

Peter Naur,U Copenhagen,

1928 -BNF : Backus-Naur (or Backus Normal) Formsyntactic metalanguage in which the grammar

of Algol 60 was fomally defined.

Coding in English???

'DIVIDE CAKE INTO THREE”

The use of COBOL cripples the mind;

its teaching should, therefore,

be regarded asa criminal offence.

E. W. Dijkstra

Panini (ca. 550BC) constructed a formal grammar of Sanskrit, the Ashtadhyayi

Programming LanguagesBASIC, Darmouth College, NH, 1964

John G. Kemeny1926 -1992

Manhattan Project with John von Neumann.Princeton PhD (Type

Theory vs Set Theory) under Alonzo Church.

Mathematical assistantto Einstein.President of

Dartmouth College.Chair of Three MIle Island commission

Thomas E. Kurtz1928 -

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

More Programming LanguagesChristopher Strachey 1916 - 1975

Scion of the Bloomsbury GroupDesigned 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 -2011Developed LISP at MIT in 1958:

a Turing-complete language with a few simple operators and a notation for functions,

which provided the foundation forArtificial Intelligence.

Formal Specification & VerificationFormal syntax of a programming language defines

all valid programs in a finite collection ofrecursive 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 computationbefore and after its execution.

Formal specification of a program is a logical relation that its execution should guaranteebetweeen its input and its output.

Verification of a program is the proofthat its semantics satisfies it specification.

Many safety-critical systems are nowrequired to be formally verified.

Robin Milner, 1934 - 2010Ferranti, Cambridge,

Edinburgh, Stanford, etc.Automatic theorem proving

ML, CCS, LCF,pi-calculus.

Recursion and Invariance

Dijkstra's Ball Game The Mutilated Chessboard

Recursion and Induction:Proving that 1 + 1 = 2

The Theory NATSignaturez: NATs: NAT → NATp : NAT, NAT → NATAxiomsp(z, n) = n .....................1p(s m, n) = s p(m, n)......2

Define'0' as z'1' as s z'2' as s s z'+' as p

Proof'1 + 1'= p(s z, s z) by definition= s p(z, s z) by axiom 2= s s z by axiom 1= '2' by definition

Minis and Mainframes

The DEC PDP 8, 1965up to 32K 12-bit words.

666KHz

The IBM 360, 1964Up to 8Mb 32-bit words

1Mhz

Remote Batch Terminals

Televideo 925, 1982

The sad tale of the sheriffand the IBM sales engineer

The Single Chip MicroprocessorIntel 8008, 1971

16Kb in 8-bit words3500 transistors

800KHz$120

Intel 4004. 19704kB in 4-bit words2300 transistors

740KHz$200

Personal Computers

The MITS Altair 8800, 1975$400 kits for electronics hobbyists.

10,000 kits shippedNo 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.

Homebrew Computer Club, Silicon Valley

The 1977 Trinity

Apple IISteve Wozniak and Steve Jobs

Commodore PETChuck Peddle TRS-80

Radio Shack

Xerox PARCThe 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, 1973A 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.

Personal Computers

Atari 400, 1979The original games machine

4 million soldIBM thought of buying the

company to get it, but instead designed ...

The IBM PC, 19814.77MHz Intel 8088, up to 256Kb RAM2 floppy disk drives, open architecture

Operating system MS-DOS by Microsoftbased on QDOS, based on CP/M

$1565

Home Computers

Commodore 64, 198217 million sold BBC Model A/B, 1981

Acorn (ARM)Millions sold

Sinclair ZX Spectrum, 19825 million sold (not including clones)

Amstrad CPC464, 19843 million sold

WIMPWindows, Icons, Mice and Pointers

Apple Macintosh, 1984 8MHz Motorola 68000

MacPaint, MacWrite, Mac Draw128k, $2495256k, $2795

Widows 1.0 1985,2 years late, slow and buggy

Windows 2.0 1987Mac look-alike,

Aldus Pagemaker, Excel, Word,Corel Draw

Meanwhile … on the telephoneAlmon Brown

Strowger1839 - 1902Undertaker

First exchangeLa Porte, IN, 1892

75 subsribersFirst UK autopmatic

exchangeEpsom, 1912

Alexander Graham Bell1847 - 1922

Prof of ElocutionTelephony,

aeronautics,hydrofoil and many other inventions.Bell Labs.

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.

Stored Program ControlledTelephone Switching

First in worldNo. 1 ESS, 1965

AT&T Western ElectricSuccasunna, NJ

First in Europe10CX, 1967

ITT BTMWilrijk, Belgium

First digital exchange in world

Moorgate PCM, 1971LondonITT STC

Convergence with Telecoms

Tim Berners-LeeHypertext, 1980

plus Internet= WWW, 1989

Alec ReevesPulse code

modulation. 1937

Vint CerfTCP/IP on

Arpanet, 1972

Martin CooperMotorola DynaTac ('The Brick')

1973

Apple iPad 4s

2012

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

Ubiquitous Computing