1. Fall, 2006Computer Strtucture1 Computer Structure Nathan Friedman Fall, 2006

2. Computer Strtucture2 A Brief History The Abacus is considered to be the first mechanical computing device

3. Fall, 2006Computer Strtucture3 Mechanical Calculators 1612 – John Napier used floating point arithmetic and invented the logarithm 1622 – William Oughtred created the slide rule based on Napier’s logarithms. This was the primary calculator used by engineers until the 1960’s 1642 – Blaise Pascal created a machine that could add and subtract, automatically carrying numbers 1673 – Gottfried Leibnitz built a calculator that could multiply as well

4. Fall, 2006Computer Strtucture4 Mechanical Calculators 1612 – John Napier used floating point arithmetic and invented the logarithm

5. Fall, 2006Computer Strtucture5 Mechanical Calculators 1612 – John Napier used floating point arithmetic and invented the logarithm 1622 – William Oughtred created the slide rule based on Napier’s logarithms. This was the primary calculator used by engineers until the 1960’s

6. Fall, 2006Computer Strtucture6 Mechanical Calculators 1612 – John Napier used floating point arithmetic and invented the logarithm 1622 – William Oughtred created the slide rule based on Napier’s logarithms. This was the primary calculator used by engineers until the 1960’s 1642 – Blaise Pascal created a machine that could add and subtract, automatically carrying numbers

7. Fall, 2006Computer Strtucture7 The Pascaline -- 1642

8. Fall, 2006Computer Strtucture8 Mechanical Calculators 1612 – John Napier used floating point arithmetic and invented the logarithm 1622 – William Oughtred created the slide rule based on Napier’s logarithms. This was the primary calculator used by engineers until the 1960’s 1642 – Blaise Pascal created a machine that could add and subtract, automatically carrying numbers 1673 – Gottfried Leibnitz built a calculator that could multiply as well

9. Fall, 2006Computer Strtucture9 The Industrial Age Joseph-Marie Jacquard invented an automatic loom using punched cards to control patterns in the fabrics. (Leading to riots against replacing people by machines.)

10. Fall, 2006Computer Strtucture10 Charles Babbage 1822 – Charles Babbage designed the Difference Engine for comuputing navigational tables 1833 – Designed the Analytical Engine that had the basic components used in a modern computer 1847-1849 – Work on Difference Machine but technology too primitive to build it. In 1991 the Science Museum in London built it

11. Fall, 2006Computer Strtucture11 The World’s First Programmer Ada Augusta King, Countess of Loveless adds notes and documentation on Analytical Engine. She writes first program.

12. Fall, 2006Computer Strtucture12 The Difference Engine

13. Fall, 2006Computer Strtucture13 Herman Hollerith 1890 Hollerith won competition for developing data processing equipment for the US Census Founded Hollerith Tabulating Company that became IBM in 1924

14. Fall, 2006Computer Strtucture14 Early Modern Machines 1935-38 Konrad Zuse developed Z-1 and Z-2 computers using binary arithmetic 1936-39 John Vincent Atanasoff and John Berry built ABC computer for solving linear systems in Physics. Introduced ALU and rewriting memory.

15. Fall, 2006Computer Strtucture15 Early Modern Machines 1943 Alan Turing built Colossus used to break German codes encrypted using ENIGMA machine 1944 – Harvard Mark 1 used to compute artillery and navigation tables

16. Fall, 2006Computer Strtucture16 The First Computer Bug 1945 Grace Murray Hopper found bug killed in jaws of electromechanical relay on Mark II computer at Harvard

17. Fall, 2006Computer Strtucture17 ENIAC The First Electronic Computer 1943 Work started on ENIAC at University of Pennsylvania under John Mauchly and J. Presper Eckert with Herman Goldstein A general purpose computer used for computing artillery tables

18. Fall, 2006Computer Strtucture18 ENIAC Used 18,000 vacuum tubes U shaped, 25m long, 2.5m high, 1m wide Programmed by plugging cables and setting switches From 1 hour to 1 day to program

19. Fall, 2006Computer Strtucture19 Von Neumann Computer 1944 – John von Neumann joined ENIAC team. Credited with the idea of storing programs as numbers 1945 – von Neumann proposed a stored program computer called EDVAC

20. Fall, 2006Computer Strtucture20 The Late 1940’s 1947 – William Shockley, John Bardeen, Walter Brattain invent the transistor 1949 – Maurice Wilkes at Cambridge developed EDSAC, the first large scale, fully operational stored program computer 1951 – Remington-Rand sold Univac 1 to US government for $1,000,000

21. Fall, 2006Computer Strtucture21 The 1950’s IBM produces series of compters with Jean Amdahl as chief architiect Memory upgraded to magnetic core memory, magnetic tapes and disks with movable read/write heads 1957 – Fortran introduced 1958 – Integrated Circuit invented

22. Fall, 2006Computer Strtucture22 The 1960’s 1963 – ASCII code introduced 1965 – IBM/360 introduced using integrated circuits 1965 – DEC introduced PDP-8, first minicomputer 1969 – Work began on ARPAnet (the predecessor of the internet)

23. Fall, 2006Computer Strtucture23 The Early 1970’s 1971 – Intel 4004 the first microprocessor and the first floppy disk introduced 1973 – Xerox invents Ethernet 1775 – First PC, MITS Altair 8800 (no keyboard, no display, no auxilliary storage) Bill Gates and Paul Allen wrote a BASIC compiler for the Altair, their first product

24. Fall, 2006Computer Strtucture24 The Later 1970’s 1976 – Steve Jobs and Steve Wozniak develop Apple I in their parent’s garage 1976 – Cray-1, first supercomputer announced

25. Fall, 2006Computer Strtucture25 IBM PC 1981 – IBM enters market with IBM PC based on Intel 8088 chip Release of Microsoft DOS for the PC 1982 Computer chosen by Time Magazine as “Man of the Year”

26. Fall, 2006Computer Strtucture26 Apple Macintosh 1984 – Macintosh introduced, based on Xerox Alto. The icon and mouse became the main tools for interacting with computers

27. Fall, 2006Computer Strtucture27 Computer Architecture At the lowest level a computer is just a collection of switches that can be on or off (representing 1 and 0). The circuitry is organized into components that serve different functions such decoding bit sequences, carrying out simple arithmetic operations, etc.

28. Fall, 2006Computer Strtucture28 Von Neumann Machines Modern computers are called Von Neumann Machines John Von Neumann is credited with the idea that programs can be encoded and stored in the memory just like data A control unit transfers instructions from the memory into registers so that a processing unit can execute them

29. Fall, 2006Computer Strtucture29 The 5 Classic Components CPU Computer Control Registers Memory Input Devices Output Devices

30. Fall, 2006Computer Strtucture30 The Intel Pentium Processor Schematic Layout

31. Fall, 2006Computer Strtucture31 The Von Neumann Model Programs and data are both stored in the main memory of the machine There is one CPU (Central Processing Unit) The CPU has a control unit that fetches program instructions from memory, decodes them and executes them

32. Fall, 2006Computer Strtucture32 The Von Neumann Model Data is loaded from memory into registers in the CPU The CPU contains circuitry to perform basic arithmetic operations and to compare values, placing the results into registers The values in the registers can be stored in main memory

33. Fall, 2006Computer Strtucture33 Input / Ouput Input Output Those are only the ones I came up with when I wrote this slide…

34. Fall, 2006Computer Strtucture34 The Von Neumann Model Input devices (keyboard, pda, cell phone,...) allow us to place data (and programs) into memory Output devices allow us to display values stored in memory (on screen, pda, cell phone,...)

35. Fall, 2006Computer Strtucture35 Low Level Programming Programmers in the late 1940’s had to use binary numbers to encode the instructions and the data This was very time consuming and error prone so written mnemonic codes were created. Programs were written using these codes and then translated into binary by hand Soon programs were written to convert these symbols to binary. These programs are called assemblers and the instruction names are called assembly language

36. Fall, 2006Computer Strtucture36 Assembler Example We may want to evaluate the expression f = (g + h) – (i + j) Assembly program (where all the names refer to registers) add t0, g, h add t1, i, j sub f, t0, t1 Load and Store instructions are part of the assembly language and allow transferring data values between memory and registers

37. Fall, 2006Computer Strtucture37 Assembly Language Low level langauage Simple instructions of the form op result, arg1, arg2 Machine dependent – each processor has its own assembler

38. Fall, 2006Computer Strtucture38 High Level Languages Programming in assembly language is still difficult and tedious Programs are very specific to specific machines High level languages provide a more natural mathematically based formalism for expressing algorithms

39. Fall, 2006Computer Strtucture39 High Level Languages High level languages Hide details of memory allocation Allow expressing complex operations together, not just one step at a time Provide a more natural way of programming Allow programs to be ported from one machine to another

40. Fall, 2006Computer Strtucture40 High Level Languages These languages make it easier to write programs but they are still very formal, precisely structure languages that follow very specific syntax rules In addition to learning how to formulate algorithms for the computer, we will have to learn the rules for these languages

41. Fall, 2006Computer Strtucture41 How Does This Work Programs written in a high level language are translated into assembly/machine level programs A program called a compiler does this translation This program is stored in memory by a loader We can then execute the program

42. Fall, 2006Computer Strtucture42 The Translation Process compiler source program assembly program linker/loader native code

43. Fall, 2006Computer Strtucture43 Source Program A program written in a high level language (FORTRAN, C, Java, C++, Ada) Created with a text editor in human readable form File name extension often says what language is used (a1.f90, a4.c, test.java)

44. Fall, 2006Computer Strtucture44 Compiler A program that analyses the source program and translates it into a form the computer can understand Result is not readable by humans Each high level language requires its own compiler

45. Fall, 2006Computer Strtucture45 Linker/Loader The Linker combines the assembler code with other programs that were compiled another time or are standard programs available in libraries (sin, sqrt, etc) The Loader puts the complete program in memory and begins execution with the first instruction

46. Fall, 2006Computer Strtucture46 Coming Up Next In our next lecture we begin to look at a high level language, FORTRAN We will begin writing actual programs