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Mongolia International University Operating Systems Operating Systems Chapter 2 Chapter 2 B.M.H B.M.H

Computers3 Ch2

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Text of Computers3 Ch2

  • 1. Operating Systems Chapter 2 B.M.H

2. Learning Objectives

  • Software Classification
  • System Software
  • Operating System
  • OS of PCs
  • NOS

MIU 3. Computer System

  • Hardware
    • Input devices
    • Processor (CPU)
    • Output devices
    • Secondary storage
  • Software
    • System software
    • Application software
  • People

MIU 4. Software

  • System software
  • all programs related to coordinating computer operations
    • Operating systems
    • Programming language translators
    • A variety of utility programs
  • Application software
  • allows user to perform useful work
    • Word processing, spreadsheet software, etc

MIU 5. System SW

  • When you think of a computer, what first comes into your head?
    • The physical component
      • like the monitor, keyboard, or mouse
    • The applications that run on your computer
      • like word processing, video game, internet browsing

MIU 6. Operating System

  • Anoperating systemis the software needed to communicateapplication programsand computerhardwareto each other. (called OS)


  • Serves as a intermediary
    • between the applications software and the hardware
  • The fundamental software
    • that controls access to all other hardware and software resources


  • A set of programs
    • that lies between the applications software and the hardware
    • Kernel: the most important program in OS
    • Can be divided as remaining in memory
      • Resident : Kernel
      • Nonresident : other OS programs

MIU 10. Kernel

  • The program that manages the OS
  • Most of it remains in memory
    • Referred to asresident
  • Controls the entire OS
  • Loads into memory other OS programs (called nonresident) from disk storage only as needed

MIU 11. Kernel MIU A kernel connects the application software to the hardware of a computer. 12. Booting

  • The process of loading the OS into memory
  • When computer is turned on,
    • A small program stored in a ROM chip performs some internal HW component tests,
    • Then loads the kernel from the hard drive into the computer s memory
  • Calledbootstrapping

MIU 13. OS

  • Three main functions
    • Managing the computer s resources,
      • such as the CPU, memory, disk drives and printers
    • Establishing auser interface
    • Executing and providing services for applications software

MIU 14. User interface

  • Determines how the user interacts with the OS
    • Interface : inter + face
    • : a way of presenting information to and obtaining information from a user
  • Two basic forms
    • Command-line interface
    • Graphical user interface (GUI)

MIU 15. User interface

  • Command-line interface
    • Text-based
    • Requires you to type in complete OS commands
    • Ex) MS-DOS, Unix, Linux, many large-computer OSs
  • Graphical user interface (GUI)
    • Visual images and menus to allow users to enter commands
    • Ex) Windows, Mac OS, some installations of Linux and Unix

MIU 16.

  • OSs for Personal Computers
  • OSs for Networks
  • OSs for Large Computer Systems

MIU Index 17. OS for personal computers

  • When you buy something for your computer, you must know
    • not only the OS the computer has,
    • but also about itsplatform

MIU 18. OSs for Personal Computers

  • The SW is grouped according to the platform, on which the SW can run.
  • Platform
    • A combination of computer hardware and operating system software
    • Most common families of platforms
      • Windows family : (referred as Wintel)
        • Microsoft Windows + Intel processor based PC
      • Macintosh family
        • Mac OS + Motorola processor
      • Unix family
        • Unix + all families of processors

MIU 19. MIU 20. MS-DOS

  • Called DOS (Disk Operating System)
  • Command-line user interface
    • C: (disk drive)
    • > : prompt
      • a signal that the system is prompting you to do something
      • the only visible result of booting
      • At this point, you must type command

MIU 21. Microsoft Windows

  • GUI
    • Icons, menus (pull-down menus, pop-menus)
  • Three branches serving different users
    • Home/consumer market
      • Windows 9x (95, 98, ME)
    • Corporate market
      • Windows NT, 2000
    • Both the consumer and corporate
      • Windows XP
    • For pocket computers and Internet appliance
      • Windows CE

MIU 22. MIU 23. MAC OS

  • The first commercially successful GUI
    • Based on concepts developed at Xerox s PARC research center in Palo Alto, California
  • MAC OS X
    • Enhancement in multimedia support and multitasking-the ability to do several things at once.

MIU 24. MIU 25. UNIX

  • A multiuser time-sharing OS
  • A character-based system with a command-line user interface
  • The primary OS in use on Internet server, today
  • Run on about every type of computer available from microcomputers to mainframes


  • Linus Torvalds, a student at the Univ. Of Helsinki in Finland
    • Created the kernel of a Unix-like OS
    • Made the source code available to the public free of charge
  • Command-line interface, also provide a GUI

MIU 27. OSs for Networks

  • NOS (Network Operating System)
    • An extension of OSs for PCs
    • Designed to let computers on a network share resources
    • Similar to a standard OS but include special features for handling network functions
    • Ex) Windows 2000


  • Functions
    • Resource sharing on a network
      • Such as hard disks and printers
    • Data security
      • Does this user have the right to that data?
    • Troubleshooting
      • Computer *** on the network failed to receive a message intended for it
    • Administrative control
      • Track the online hours and track the number of messages to and from each computer


  • In a client/server relationship
    • Parts of the NOS : on Server computer
      • file access, management programs
    • Other NOS components : on Client computer
      • software that permits requests to the server and messages to other computers
      • Client computers has its own OS (ex, Windows ME)