Courses/Computer Science/CPSC 203/CPSC 203 2007Fall L04/CPSC 203 2007Fall L04 Lectures/Lecture 16

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Lecture 16

We quickly review the basic boolean logic patterns from last class (what I called 'ground 0' for computer science). Today we build up from Ground 0 the basic parts of a computer system from a historical perspective. First we begin with the 'idea' of a computer, the Turing Machine. Then we move to how that idea was translated into the first computers using the Von Neumann Architecture. Finally we "dream up" the ideal modern-day computer.

The objectives of today's class are:

  • House Keeping
    • Assignment 1 submission -- Technical Glitches -- contact your TA directly
    • Group Projects -- Should have project argument set out, and switch to filling out the web presentation
    • 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 -- class average was 72+ %, with a half-dozen perfect papers.

  • Topics
    • Review basic boolean logic patterns
    • Build up the idea of computer systems

Glossary (from last class)

  • Boolean Logic
  • Circuit
  • Terms of Boolean Logic

From the Abacus to the Modern Computer

Long before the computer -- the 'idea' of a computer has been fascinating humans. Interesting fact: At Los Alamos -- computers were human beings who did computations on a pad of paper, and passed their results to the next person.

The Turing Machine is the Idea of a computer


A Turing Machine has:
  • Tape (where the data is read from and written) of infinite size
  • A Head (that can read/write from the tape)which has a series of states
  • A Table (of instructions). For every combination of Tape-Value/Head-State it gives an action on the tape and an action on the head
  • A State-Register -- stores the state of the Table (i.e. the last instruction).

Imagine the Reading Head is a person who has memorized a table of instructions. The 'Tape" can be a row of people who call out a number. The Table is the computer program.

Our question is: will the Head-person ever stop working? This is called the 'Halting Problem'.

The Von Neuman Architecture is the basic design of a Computer


A Von Neuman Machine has:
  • Memory -- stores data and programs
  • Control Unit and Arithmatic/Logic Unit -- i.e. the central processing unit.
  • Input/Output -- a way of getting data and sending data.

Finally We have the Modern Computer

A modern computer has:
  • Hardware and software
    • Hardware includes:
      • CPU
      • Various Forms of Memory
      • The Bus along which data moves
      • Various peripheral devices (monitors, usb, keyboards)
    • Software includes:
      • Operating System Kernel -- the essential software that runs at all times
      • Systems Software -- makes the computer convenient for you to use
      • Applications -- lets the computer do the things you want it to

Let's Design An (Ideal) Computer System

In terms of the items above -- make a list of the design features for an ideal computer. Each group will choose a single system to focus on.

The terms of Boolean Logic were illustrated by their respective Truth Tables. See also Wikipedia: (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: Finally, logic gates were combined to build more complex circuit diagrams :

For more on Boolean Logic please see:

A Computer Sciece oriented summary of Boolean logic is at:



TIA 4th Edn: Chapter 9 pp 406- 431

TIA 3rd Edn: Chapter 9 pp 386 - 409

Lets Build A Computer

TIA 4th Edition: Chapter 5, 202 - 214; Chapter 6, 246 - 265

TIA 3rd Edition: Chapter 5, 190 - 202; Chapter 6, 234 - 252


Modern Computer

Operating Systems Concepts. 7th Edition. By Silberschatz et al. Slides from Chapt. 1 of this book are on BB -- pay particular attention to the 3 graphical slides covered in lecture:

  • 1.6 -- 4 Components of a Computer System
  • 1.10 -- Computer System Organization
  • 1.21 -- Storage Device Hierarchy

Boolean Logic and Circuits

The primary resource for the Boolean Logic and ciruits 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.