The Basic Computer
UNIT 1 THE BASIC COMPUTER Structure 1.0 1.1 1.2 1.3 1.4
Introduction Objectives The von Neumann Architecture Instruction Execution: An Example Instruction Cycle 1.4.1 1.4.2
1.5
1.0
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Interrupts Interrupts and Instruction Cycle
Computers: Then and Now 1.5.1 1.5.2 1.5.3 1.5.4 1.5.5
1.6 1.7
Page Nos.
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The Beginning First Generation Computers Second Generation Computers Third Generation Computers Later Generations
Summary Solutions/Answers
29 29
INTRODUCTION
The use of Information Technology (IT) is well recognised. IT has become a must for the survival of all business houses with the growing information technology trends. Computer is the main component of an Information Technology network. Today, computer technology has permeated every sphere of existence of modern man. From railway reservations to medical diagnosis, from TV programmes to satellite launching, from matchmaking to criminal catching ─ everywhere we witness the elegance, sophistication and efficiency possible only with the help of computers. In this unit, you will be introduced to one of the important computer system structures: the von Neumann Architecture. In addition, you will be introduced to the concepts of a simple model of Instruction execution. This model will be enhanced in the later blocks of this course. More details on these terms can be obtained from further reading. We have also discussed about the main developments during the various periods of computer history. Finally, we will discuss about the basic components of microprocessors and their uses.
1.1
OBJECTIVES
After going through this unit you will be able to: • • • • •
1.2
define the logical structure of the computer; define the instruction cycle; define the concept or Interrupt; discuss the basic features of computers; and define the various components of a modern computer and their usage.
THE VON NEUMANN ARCHITECTURE
The von Neumann architecture was the first major proposed structure for a generalpurpose computer. However, before describing the main components of von Neumann
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