Introduction

• Please the Preface, page V, To The Student and XI, General Organization and Coverage
• Chapter 1 Goals
  • Motivate the study of computer architecture
  • Learn basic terminology
  • Discuss various computer models
  • Examine basics of a computer system
• In the last 50 years computers have had a tremendous impact on our lives.
• This has expanded greatly in the last 20 years
• And people predict that it will continue to grow
• What has made all of this possible?
• What is Computer Science?
  • Programming
  • The study of programming?
  • The study of Algorithms?
  • The study of hardware?
• Some algorithms are computationally infeasible, or they would take far too long to complete.
  • Trying to crack a 14 character password by brute force
• This class is here because:
  • Understanding how the computer works helps us to determine what is feasible
  • Understanding how the computer works helps us make programs that are more efficient.
  • Understanding how performance of computers is measured is essential if you are involved in purchasing/specifying computer systems
• Computer Organization
  • How does a computer work?
  • How does data travel through the computer?
  • How do control signals change the data path?
  • How are control signals generated
  • What is a cache?
  • What is a 8x2¹⁰ memory system
  • A "mechanical" view of a computer
• Computer Architecture
  • How do I design a computer?
  • What instructions are needed?
  • How are numbers represented?
  • What types of data do I have?
  • The logical view of the computer
• an Instruction Set Architecture is the standard interface to the hardware.
  • Instructions
  • Addressing details

The Main Components of a Computer

• What is the difference between hardware and software?
• Consider a simple calculator:
  • 10 digit keys
  • 4 operators (+,-,*,/)
  • 1 enter key (=)
  • operations are in the form
    • digits operator digits enter
    • 45 + 34 =
    • 124 / 2 =
  • The result is printed.
  • Can you write software to do this?
  • Can hardware do this?
  • What is the difference?
• The Principle of Equivalence of Hardware and Software
  • Anything that can be done with software can also be done with hardware, and anything that can be done with hardware can also be done with software
  • in some sense hardware and software are the same thing
  • But only if we don't look at speed.
  • Java for example
    • Java code is compiled to byte code
    • This is then run on the java virtual machine
    • Which is an implementation of a computer
  • Interesting point: "Modern computers are actually implementations of algorithms that execute other algorithms"
  • Special purpose computers vs general purpose computers
• For hardware we will consider three basic systems
  • A processor to interpret and execute programs (ch 4,5)
  • A memory system to store data and programs (ch 6)
  • A mechanism for transferring data to/from the computer (ch 7)