CS 146 The Big Picture in Computer Science

1. CS 146The Big Picture in Computer Science Prof. Daniel Ernst January 24th, 2011

2. Welcome to CS 146! • Instructor • Dan Ernst • Office: P 139 • ernstdj@uwec.edu • Course Web Site: • http://www.cs.uwec.edu/~ernstdj/courses/cs146/ • D2L: https://uwec.courses.wisconsin.edu (for grades)

3. Getting Information • Go to the website • Slides, Readings, Other stuff from class • Assignments • Office Hours • Read your e-mail! • Class e-mail group will be used by the instructor • Membership mandatory • I assume you read everything sent to this list!

4. When You Have Questions • Best ways to contact me: • Come to office hours – Phillips 139 • Wednesday 9 – 11am • Friday 1 – 3pm • OR by appointment (just e-mail or call my office) • Send me an e-mail: ernstdj@uwec.edu

5. What This Course is About • This course is NOT about: • Major technical skills (i.e. programming) • How to use computers • This course IS about: • the breadth of Computer Science as a field • the logistics of CS at UWEC • how CS relates to liberal education and to society • getting a glimpse at the “end zone” of the profession • how to think like a Computer Scientist

6. Overall Course Grading

7. Introduction to Computer Science Some of these slides are based on material from the ACM Computing Curricula 2005

8. What Is Computer Science? • Science? • Do computer scientists do experiments? (hypothesis, test, evaluate) • Engineering? • Do computer scientists build things? • Math? • Abstraction? • Art? • Are there creative elements in computer science? • A combination of some or all of these? • Something else?

9. What Is Computer Science? (2) Theory? Practice? Infrastructure? Configuration? Development? Management?

10. What Is Computer Science? (3) Systems? Applications? People? Hardware? Software?

11. What is a Computer Scientist?

12. What Do Computer Scientists Do? Talk to clients and each other Build systems (hardware and software) Research possible approaches, tools Gather requirements for a system Analyze requirements Develop test cases for a system Design solution systems Design interfaces Implement solution systems Integrate systems Maintain systems (bug fixes, enhancements)

13. I Like Learning by Example… …so here are some Computer Scientists: http://www.youtube.com/watch?v=jq_EcstLlfE#t=0m24s

14. History of Computers When was the computer invented? Depends on what you mean by “computer”… A computer does not need to be electric, nor even have a processor, nor RAM, nor even hard disk. The minimal definition of a computer is anything that transforms information in a purposeful way. “The essence of the computer is not electronic. Computers can be made from toothpicks and bottlecaps, or toilet paper and pebbles.” - George Teschner

16. Early “Computers” • Bones, other objects for counting – B.C. • Abacus (counting and calculating) – 3rd century A.D. • John Napier’s logarithmic tables, slide rule – 1600’s • Blaise Pascal’s machine (addition) – 1640’s • Gottfried Leibniz’s mechanical calculator – 1673 • Joseph Jacquard’s loom (punched metal cards) - 1804 • Charles Babbage • Difference Engine (specialized) designed – 1820’s • Analytical Engine (generalized) designed – 1830’s

17. Babbage’s Analytical Engine • “Mill” – processor • “Store” – memory • Also, concepts of: • Input and output • Generalized program execution • “We may say most aptly that the Analytical Engine weaves algebraical patterns just as the Jacquard-loom weaves flowers and leaves” – Ada, Countess of Lovelace

18. More Computing Machines • Herman Hollerith, statistical tabulator for the U.S. Census Bureau, using paper punch cards for data – 1890 • Later created company named International Business Machines Corporation • Quiet period until 1940’s • Mark 1 – mathematical computer with electro-mechanical relays, 1943 • John von Neumann – computer design with input, output, memory, control, and arithmetic/logic unit, 1945 • ENIAC, built by J. Presper Eckert and John Mauchly – first large-scale electronic (vacuum tubes) digital computer, 1946 • First transistor – John Bardeen, William Shockley, and Walter Brattain, 1947 • UNIVAC, first commercial computer, sold in 1951

19. Generations of Computing Infrastructure 1940s and early 1950’s – 1st Generation (vacuum tubes, very large systems, programming in machine language) 1956-1963 – 2nd Generation (transistors, large systems, assembly language) 1964-1971 – 3rd generation (integrated circuits, high level languages (e.g. FORTRAN, C) 1971 – present – 4th generation (microprocessors, new high level languages (e.g. C++, Java, C#) plus 4GL’s (e.g. Structured Query Language for database systems)

20. What about Computing? • We’ve talked about the history of Computers • AKA the history of automated computing devices “Computer science is no more about computers than astronomy is about telescopes.” - E. W. Dijkstra • What about computing?

21. Computer Scientistof the Week Alan Turing (1912-1954)

22. Alan Turing • Attended King’s College, Cambridge in Mathematics • During that time, he published a paper that describes the underlying characteristics needed for a “Universal Computing Device”. • Gave a very concrete description of such a device, called a “Turing Machine” Mathematician, Logician, Cryptanalyst, Computer Scientist

23. Church-Turing Thesis • Based off of this work, he went to study at Princeton with Alonzo Church, who was working on similar things. • Their collaboration led to the foundations of algorithms – now called the Church–Turing thesis • The thesis claims that any calculation that is possible can be performed by an algorithm running on a computer, provided that sufficient time and storage space are available. (universality)

24. Alan Turing • During WW II, Turing was a key figure at Bletchley Park, home of the British codebreakers. • Helped invent automated machines to brute-force German Naval codes. • In 1942, trained US cryptanalysts • Awarded the Order of the British Empire (OBE) for his wartime efforts • Although they couldn’t actually tell anyone why he received it in detail.

25. Conviction and Death • In 1952, Turing was convicted of “gross indecency” • A blanket term which included any homosexual activity • He was sentenced to “chemical castration” – forced injections of estrogen to “reduce libido”. • In 1954, Turing was found dead by his cleaner. He died of cyanide poisoning, most likely by his own hand. He was 41.

26. Legacy Developed the theoretical foundations of Computer Science as a field. By many accounts, the work at Bletchley Park likely won World War 2 for the Allies In 2009, the British government directly apologized for the “appalling” treatment Turing received, likely resulting in his death.

27. Computer Scientistof the Week Alan Turing (1912-1954)