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Who Invented the Computer? Babbage, Atanasoff , Zuse , Turing or v on Neumann?

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Who Invented the Computer?Babbage, Atanasoff, Zuse, Turing or von Neumann?

Raj Reddy

Carnegie Mellon University

Sep 23, 2013

Talk given at Heidelberg Laureates Forum on

Origins of Computing

- Invention of Writing 3000BCE
- Hieroglyphs, Kanji Characters
- Mesopotamia: Sumerian cuneiform writing on clay tablets
- Egypt: writing in hieroglyphic script

- Invention of Alphabet for simplified writing and learning, and communication with slaves

- Hieroglyphs, Kanji Characters
- Invention of Printing1450CE
- Guttenberg Press
- Democratization of knowledge

- Invention of Computer1950CE
- Passive knowledge to active knowledge

Roman Indo-ArabicBinary

I1 1

V5 101

X10 1010

L50 110010

C100 1100100

D500 111110100

M1000 1111101000

CXXVIII=128 = 10000000

Representing Numbers in Abacus

Bi-Quinary Representation

(also used in early computers Colossus, IBM650 and Univac)

- John Napier (1550-1617)
- Discovered
- Logarithms
- Simplifying arithmetic computations

- Logarithms
- Popularized the use of Decimal Point

- Discovered
- Slide Rule: Represents Numbers
on a Logarithmic Scale

- On a logarithmic scale an equal difference in order of magnitude is represented by
an equal distance

- On a logarithmic scale an equal difference in order of magnitude is represented by

Known for

- Co-Founder of Probability Theory
- Pascal’s Triangle for Binomial Coefficients
- Pascaline Mechanical Calculator
- Only addition and subtraction
- Pascal Programming Language namedafter him

- Only addition and subtraction

Known for

- Co-Inventor of Calculus with Newton
- Binary Number Systems (Explication de l'ArithmétiqueBinaire-1703)
- Calculus Ratiocinator: Algebra of Logic as a Calculus of Human Reasoning
- Formal Logic: Forerunner of Symbolic Logic
- Leibniz Pinwheel Calculator
- Capable of multiplication and division

- Algebra of Numbers
- Semantics of Addition, Subtraction, and Multiplication of Numbers are well understood

- Algebra of Sets and Propositions (Boolean Algebra)
- Semantics of Addition, Subtraction, and Multiplication in Boolean Algebra are sometimes different

- If X=all men and Y=all women
X+Y is all men and women

- If X = all people and Y = all children
then X-Y is all Adults

But

- X+X=X not 2X
- X.X = X not X2

- 0.X = 0 and 1.X = X

that Algebra of Switching Circuits is

equivalent to Algebra of Propositions

- Designer of the Analytic Engine
- First Programmable General Purpose Computer
- First Use of Punch Cards and Storage Registers
- First software program developed by Lady Lovelace

- Analytical Engine proposed to use a
- A Store (Memory) with 1000 50-digit words
- Arithmetic Unit (ALU)
- Sequential Control of Instructions (CPU) with Conditional Branching
- Punch Card I/O
- Software on Punch Cards Replacing Fixed Automation by Programmable Automation
- Stored Program Computer? Represents Programs as
Data, but on Punch Cards

- Missing Elements of Babbage’s Design
- No Binary Arithmetic or Floating Point
- No Working Prototype

- Proposed an Abstract Digital Computing Machine, now called a Universal Turing Machine (1936), formalizing the
- Concepts of Algorithm and Computation
- Concept of a Programmable Computer
- Concept of a Program
- and Programming

- Concept of a Stored Program Computer
- Concept of a Subroutine
- Read, Write and Erase on an Infinite Paper Tape
- Modern Computers also Read, Write and Erase
- albeit with finite memory

- Modern Computers also Read, Write and Erase

- Stibitz is acknowledged as an early pioneer in the digital computer revolution
- BTL1 is known for
- Complex Multiplication and Division
- (x + yi)(u + vi) = (xu – yv) + (xv + yu)i
- 3 multiplications and 3 additions
- Needs a sequence of calculations and
storing intermediate results

- Fixed Function – Not programmable

- First Computing Device ever used
Remotely over Phone Lines

- Boolean Logic for Circuit Design

- Complex Multiplication and Division

- Howard Aiken is acknowledged as an early pioneer in the digital computer revolution
- Harvard Mark I is known for
- One of the Largest Computers 51’x8’x2’
- Weighing 10,000 pounds

- Electro-Mechanical
- Programmable
- Sequence of instructions from
24 channel paper tape

- No conditional branching

- Sequence of instructions from
- Decimal Arithmetic
- 72 Storage Counters with 23 digit
signed decimal numbers

- One of the Largest Computers 51’x8’x2’

- John Atanasoff is acknowledged as an early pioneer in the digital computer revolution
- Atanasoff-Berry Computer (ABC)

- ABC is known for
- First Electronic Digital Computer
- arithmetic logic functions were fully electronic
- logic gates ranged from inverters to two
and three input gates

- Binary digits represent all numbers
and data

- Fixed Function – Not Programmable
- No Stored Program

- Regenerative capacitor memory

- First Electronic Digital Computer

- KonradZuse is acknowledged as an early pioneer in the digital computer revolution
- Z3 is known for
- First working, program-controlled, general-purpose, electro-mechanical relay computer
- Sequence of Instructions on Tape
- Conditional Branching missing

- First to use Binary Representation
- First use of Floating Point
- Single Address Instructions
- Operation, Operand

- First Programmable Computer

- First working, program-controlled, general-purpose, electro-mechanical relay computer

- Bombe was an electromechanical device used to decipher German Enigma-machine-encrypted secret messages
- Developed by Alan Turing and Gordon Welchman
- Produced in 1940 at the UK Government Code and Cypher School
- Bombe was
- An Electro-mechanical Special Purpose Computer
- The First to be used in Symbolic Computation
- The First to be used as a Parallel Computer

- Colossus was the world's first electronic digital computer that was at all programmable
- Used for Code Breaking during WWII
- Colossus
- Used 2000+ state-of-the-art vacuum tubes
- First working implementation of a programmable electronic computer
- Atanasoff’s was not programmable

- Eckert and Mauchly provided key leadership in the emergence of Electronic Digital Computer
- Responsible for emergence of global digital computer industry along with IBM
- Eckert Mauchly Computer Corporation 1948

- ENIAC Known for
- First Large Scale Electronic Computer
- First to become operational
- Far Faster than any another existing computer

- Programming by Plugboard
- Too slow

- Full Conditional Branching
- Decimal Arithmetic
- 20 10-digit accumulators

- Punch Card I/O
- Led to EDVAC Report
- Training Ground for Many Successors

- First Large Scale Electronic Computer

- EDVAC Report (1945): Electronic Discrete Variable Automatic Computer
- Based on discussions with Goldstine, Eckert and Mauchly
- A Design for a Programmable Electronic Digital Computer
- a processing unit: an arithmetic logic unit and processor registers
- a control unit: an instruction register and program counter
- a memory to store both data and instructions
- external mass storage, and
- input and output mechanisms

- Concept of a Stored Program
- Concept of Instructions as Data
- Instructions and Data in same Memory

- Concept of sequential flow of control
- A “program counter” that indicates the current
point that has been reached in execution

of a program

- A “program counter” that indicates the current
- Concept of a variable
- “named” storage locations in which a value
may be stored and subsequently referenced

- “named” storage locations in which a value

- Also a Founder of Artificial Intelligence
- Designed Code Breaking Computers during WW II

- Created the Design for ACE (1945), proposing
- A Stored Program Electronic Computer
- With Binary Arithmetic
- Using Electronic Logic Circuits
- ALU, Memory (and Registers) and I/O
- Stored Program
- Conditional Branching
- Floating Point

- Commercialized by Ferranti and
English Electric in 1950s

- Manchester SSEM (UK)
- CRT memoryJun-48 Binary

- Modified ENIAC (US)
- Read Only MemorySep-48Decimal

- Cambridge EDSAC (UK)
- Mercury delay line memory May-49Binary

- Manchester Mark 1 (UK)
- CRT and magnetic drum memoryOct-49Binary

- Pilot ACE (UK)
- Mercury delay line memoryMay-50Binary

- Also CSIRAC, BINAC, UNIVAC, SEAC, Harvard MarkIII

- Babbage: FIRST to design a PROGRAMMABLE general purpose computer
- Not implemented, No Impact

- Not a programmable general purpose computer
- In spite of familiarity with Babbage’s work, did not see programmability as a central issue

- Not Electronic, No conditional execution

- No implementation, No direct impact

- Turing II (1940): FIRST to be used for Symbolic Computation and Parallel Computation
- Special purpose computer for code-braking

- Flowers (1944): FIRST working Programmable ELECTRONIC digital computer
- Not stored program, but just plug-board programming

- von Neumann: FIRST to propose the STORED PROGRAM ELECTRONIC DIGITAL COMPUTER
- widely adopted in US, many variations implemented, including EMCC and IBM

- ACE architecture used in English Electric and Ferranti Computers

Pascal, Leibniz, Stibitz, Aiken, Flowers, Eckert and Mauchly?

Babbage?

Atanasoff?

Zuse

Turing?

von Neumann?

- Babbagegot most of the elements of a Digital Computer right
- No impact

- Jane Smiley thinks Atanasoff invented the computer
- But it was not a general purpose programmable architecture
- had no impact on the future evolution

- Martin Davis believes that Turing qualifies for the title given the 1936 seminal paper
- but the Universal Turing Machine idea was largely ignored
- had little impact on the emergence of the modern computer

- Zuse got most of the elements right
- based on electromechanical components, and
- no conditional execution

- von Neumann or Turing?
- This is like asking who invented calculus: Newton or Leibniz?
- EDVAC and ACE reports defined the future of Computing

Who Invented the Computer?Babbage, Atanasoff, Zuse, Turing or von Neumann?

All of them deserve the title

“Man Who Invented the Computer”

It is amazing and inspiring that these pioneers working alone and in isolation with limited resources made as much progress

- The dawn of Computer Age?
- Advances over last 7 decades: incredible andunprecedented in the annals of science and technology
- exponential growth in computational power,
- exponential growth in memory capacity,
- exponential growth in optical bandwidth and
- exponential growth in wireless bandwidth.

- Advances over last 7 decades: incredible andunprecedented in the annals of science and technology
- Progression from
- transistors to integrated circuits to vlsito multicore
- mainframes to minis to pcs to mobile systems to warehouse scale computers
- Arpanet to Internet to Wifi to 4G to gigabit wireless
- Interpreters to compilers to www to apps

- Most importantly, we have expanded the scale and scope of the uses of computers by developing algorithms for many unconventional tasks such as
- cars that drive themselves
- any-to-any language translation
- spoken language understanding
- winning at games such as
- poker, robo-soccer, jeopardy

- winning and crashing the stock market
- Derivatives market
- Cause sub-prime financial crisis

- These are tales for another day!