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Chapter 1: Introduction

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Chapter 1: Introduction

  • What Operating Systems Do
  • Computer-System Organization
  • Computer-System Architecture
  • Operating-System Structure
  • Operating-System Operations
  • Process Management
  • Memory Management
  • Storage Management
  • Protection and Security
  • Kernel Data Structures
  • Computing Environments
  • Open-Source Operating Systems

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Operating System Concepts – 9th Edition

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Objectives

  • To describe the basic organization of computer systems
  • To provide a grand tour of the major components of operating systems
  • To give an overview of the many types of computing environments
  • To explore several open-source operating systems

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What is an Operating System?

  • A program that acts as an intermediary between a user of a computer and the computer hardware
  • Operating system goals:
    • Execute user programs and make solving user problems easier
    • Make the computer system convenient to use
    • Use the computer hardware in an efficient manner

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Operating System Concepts – 9th Edition

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Computer System Structure

  • Computer system can be divided into four components:
    • Hardware – provides basic computing resources
      • CPU, memory, I/O devices
    • Operating system
      • Controls and coordinates use of hardware among various applications and users
    • Application programs – define the ways in which the system resources are used to solve the computing problems of the users
      • Word processors, compilers, web browsers, database systems, video games
    • Users
      • People, machines, other computers

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Operating System Concepts – 9th Edition

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Four Components of a Computer System

Figure: A view of operating system services

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Operating System Concepts – 9th Edition

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Computer System Organization

  • Computer-system operation
    • One or more CPUs, device controllers connect through common bus providing access to shared memory
    • Concurrent execution of CPUs and devices competing for memory cycles

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Computing Environments - Virtualization

  • Allows operating systems to run applications within other OSes
    • Vast and growing industry
  • Emulation used when source CPU type different from target type (i.e. PowerPC to Intel x86)
    • Generally slowest method
    • When computer language not compiled to native code – Interpretation
  • Virtualization – OS natively compiled for CPU, running guest OSes also natively compiled
    • Consider VMware running WinXP guests, each running applications, all on native WinXP host OS
    • VMM (virtual machine Manager) provides virtualization services

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Operating System Concepts – 9th Edition

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Computing Environments - Virtualization

  • Use cases involve laptops and desktops running multiple OSes for exploration or compatibility
    • Apple laptop running Mac OS X host, Windows as a guest
    • Developing apps for multiple OSes without having multiple systems
    • QA testing applications without having multiple systems
    • Executing and managing compute environments within data centers
  • VMM can run natively, in which case they are also the host
    • There is no general purpose host then (VMware ESX and Citrix XenServer)

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Operating System Concepts – 9th Edition

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Computing Environments - Virtualization

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Operating System Concepts – 9th Edition