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

1. Who Invented the Computer?Babbage, Atanasoff, Zuse, Turing or von Neumann? Raj Reddy Carnegie Mellon University Sep 23, 2013 rr@cmu.edu Talk given at Heidelberg Laureates Forum on Origins of Computing

2. 3 Stages of Information Revolution • 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 • Invention of Printing 1450CE • Guttenberg Press • Democratization of knowledge • Invention of Computer 1950CE • Passive knowledge to active knowledge

3. Representing Numbers Roman Indo-Arabic Binary I 1 1 V5 101 X10 1010 L50 110010 C100 1100100 D500 111110100 M1000 1111101000 CXXVIII=128 = 10000000

4. Tools for Calculation: Abacus Representing Numbers in Abacus Bi-Quinary Representation (also used in early computers Colossus, IBM650 and Univac)

5. Tools for Calculation : Slide Rule • John Napier (1550-1617) • Discovered • Logarithms • Simplifying arithmetic computations • Popularized the use of Decimal Point • 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

6. Blaise Pascal (1623-1662) 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

7. Gottfried Wilhelm Leibniz (1646-1714) 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

8. George Boole (1815-64) • 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 • Both Algebras Agree if X=0 or 1 • 0.X = 0 and 1.X = X • Claude Shannon Demonstrated in 1938 that Algebra of Switching Circuits is equivalent to Algebra of Propositions

9. Babbage and LovelaceInventors of the First Computer and Software • 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

10. Babbage and LovelaceInventors of the First Computer and Software

11. Alan M. Turing (1912-54)Turing I: Universal Turing Machine (1936) • 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

12. George Stibitz (1904-95)BTL1 1936 • 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

13. Howard AikenASCC: Automatic Sequence Controlled Calculator(Harvard Mark I) 1936 • 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 • Decimal Arithmetic • 72 Storage Counters with 23 digit signed decimal numbers

14. John Atanasoff (1903-95)ABC 1936 • 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

15. John Atanasoff (1903-95)ABC 1936

16. KonradZuse (1910-1995)Z3 1936 • 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

17. KonradZuse (1910-1995)Z3 1936

18. Turing IIBombe (1940) • 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

19. Tommy FlowersColossus (1943) • 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

20. Eckert and MauchlyENIAC: Electrical Numerical Integrator and Computer 1945 • 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

21. John von Neumannwith Goldstine, Eckert and Mauchly • 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 • Concept of a variable • “named” storage locations in which a value may be stored and subsequently referenced

22. John von Neumann

23. Turing III: Automatic Computing Engine (ACE) Report (Dec 1945) • 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

24. Cambrian Explosion of Computers List of Stored Program Computers 1946-1950 • Manchester SSEM (UK) • CRT memory Jun-48 Binary • Modified ENIAC (US) • Read Only Memory Sep-48 Decimal • Cambridge EDSAC (UK) • Mercury delay line memory May-49 Binary • Manchester Mark 1 (UK) • CRT and magnetic drum memory Oct-49 Binary • Pilot ACE (UK) • Mercury delay line memory May-50 Binary • Also CSIRAC, BINAC, UNIVAC, SEAC, Harvard MarkIII

25. Who was the First? • Babbage: FIRST to design a PROGRAMMABLE general purpose computer • Not implemented, No Impact • Atanasoff: FIRST to develop a working ELECTRONIC digital computer with binary arithmetic • Not a programmable general purpose computer • In spite of familiarity with Babbage’s work, did not see programmability as a central issue • Zuse: FIRST to develop a WORKING programmable general computer with binary and floating-point arithmetic • Not Electronic, No conditional execution • Turing I (1936): FIRST to propose the STORED PROGRAM CONCEPT (as part of Universal Turing Machine) • No implementation, No direct impact

26. Who was the First? • 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 • Turing III (1945): FIRST to anticipate a RISC ARCHITECTURE for a programmable electronic computer • ACE architecture used in English Electric and Ferranti Computers

27. Who is the Inventor of Modern Computer? Pascal, Leibniz, Stibitz, Aiken, Flowers, Eckert and Mauchly? Babbage? Atanasoff? Zuse Turing? von Neumann?

28. Relative Contributions of Various Pioneers

29. Programmable?

30. Stored Program?

31. Binary Arithmetic?

32. Working Prototype?

33. Impact on SocietyCommercial Availability

34. In Summary • 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

35. 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

36. Post 1945 • 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. • 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

37. Post 1945 (cont) • 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!