1. CSE111: Great Ideas in Computer Science Dr. Carl Alphonce 219 Bell Hall Office hours: M-F 11:00-11:50 645-4739 alphonce@buffalo.edu

2. Announcements No recitations this week or next. First meeting of recitations in week of 1/25- 1/29. Extra copies of syllabus available at front of class 2

3. cell phones off (please) 3

4. Today Course introduction –Algorithm –Incompleteness Theorem –Computing Machines –Abstraction 4

5. Algorithm informally: a sequence of steps to perform some task 5

6. http://commons.wikimedia.org/wiki/File:Recipe.gif http://commons.wikimedia.org/wiki/File:Recipe.gif (public domain) 6

7. http://commons.wikimedia.org/wiki/File:Chopin_Op.10_No.9.PNG http://commons.wikimedia.org/wiki/File:Chopin_Op.10_No.9.PNG (public domain) 7

8. Incompleteness Theorem Kurt Gödel 1930’s “in any mathematical theory encompassing our traditional arithmetic system, there are statements whose truth or falsity cannot be established by algorithmic means” [p. 4] 8

9. Computing Machines Abacus – data storage Fixed algorithm machines –Pascal (1623-1662) –Leibniz (1646-1716) –Babbage (1792-1871) (difference engine) General computation machines –Babbage (analytical engine) –Jacquard (1752-1834) –Stibitz (1940)/Mark I (Bell Labs, 1944) - electromechanical –Atanasoff-Berry (1941) –ENIAC (1946) 9

10. Abstraction Ignore unimportant details Focus on a given level of granularity Way of handling complexity 10

11. Representing data Next class we will begin discussing how data is represented. We will explain how all data is represented using sequences of just two symbols, ‘0’ and ‘1’. 11