Courses/Computer Science/CPSC 203/CPSC 203 2007Fall L04/CPSC 203 2007Fall L04 Lectures/Lecture 15

Lecture 15
Today we introduce 'ground 0' in computer science. Boolean logic. The basic construct on which everything else is built. The core idea is that at the lowest levels a computational system can only distinguish between two states -- call it 1 and 0 -- and everything is built up from that groundwork.

The objectives of today's class are:


 * House Keeping
 * Assignment 1 submission -- Technical Glitches -- contact your TA directly
 * Reminders:
 * Final Exam Date and Time has been set: Monday Dec 17, 12-2p.m. (room unknown).
 * Mid-term results will be posted by Next Monday


 * Topics
 * Quick 2nd look at Assignment 2 in preparation for next week's labs
 * Introduction to Boolean Logic

Glossary

 * Boolean Logic
 * Circuit
 * Terms of Boolean Logic
 * AND
 * OR
 * NOT
 * XOR
 * Logical Implication; If X, Then Y; X-->Y
 * Logical Implication has some philosopical 'difficulties' associated with it (though we use the idea in comp sci all the time). see : http://en.wikipedia.org/wiki/Logical_implication

From Venn Diagrams to Boolean Logic

 * 1) Venn Diagrams Revisited
 * 2) The Idea of a Truth Table (as a logical function).
 * 3) The Idea of a Circuit (as a way of physically implementing a Truth Table).
 * 4) The Basic Truth Tables and Functions (on which everything else is built)

The terms of Boolean Logic were illustrated by their respective Truth Tables. See also Wikipedia: http://en.wikipedia.org/wiki/Truth_table (note that in class we used 1 where they use "T", and we used 0 where they use "F"). Truth table values were then related to Logic gates: http://en.wikipedia.org/wiki/Logic_gates. Finally, logic gates were combined to build more complex circuit diagrams : http://en.wikipedia.org/wiki/Logic_gates.

For more on Boolean Logic please see: http://en.wikipedia.org/wiki/Boolean_Logic

A Computer Sciece oriented summary of Boolean logic is at: http://en.wikipedia.org/wiki/Boolean_logic

TEXT READINGS
TIA 4th Edn: Chapter 9 pp 406- 431 TIA 3rd Edn: Chapter 9 pp 386 - 409

Resources
The primary resource for this lecture was:
 * Ones & Zeros -- Understanding Boolean Algebra, Digital Circuits and the Logic of Sets. 1998. By John R. Gregg

Supplementary References are:


 * Logic. A Very Short Introduction. 2000. By Graham Priest.
 * Logic Made Easy. How to Know When Language Decieves You. 2004. By Deborah J. Bennett.
 * Feynman Lectures on Computation. 1996. By Richard P. Feynman.