Cabrillo College

							Cabrillo College



       CIS 172 Survey of
       Operating Systems
                                         Chapter


                                            1
     Introduction to Operating Systems

An Overview of Microcomputers
What’s Contained in and Attached to a
Microcomputer?
Purpose, Types, and Functions of Microcomputer
Operating Systems
Yesterday’s Operating Systems
Desktop OSs Available Today
     Learning Objectives
   Describe the microcomputers in use today
   Identify common computer hardware components
   Describe the purpose and functions of
    microcomputer operating systems
   Describe major events in the evolution of
    microcomputer operating systems
   List and compare the common microcomputer
    operating systems
An Overview of Microcomputers

   What is a Microcomputer?
    –   A computer built around a microprocessor
            Microprocessor performs calculations or processing
            A personal computer (PC) is a microcomputer
             that complies with hardware standards set and
             supported by Microsoft and Intel
An Overview of Microcomputers

   What Types of Microcomputers Are Used
    Today?
    –   Desktops and laptops
    –   Servers – provide services to other computers
    –   Handheld devices – designed for a specific
        purpose
    What’s Contained in and
    Attached to a Microcomputer?

   Microprocessor
    –   Also known as the CPU or processor
    –   Central component of a microcomputer
    –   Performs calculations
    –   One or more per microcomputer
What’s Contained in and
Attached to a Microcomputer?

   Microprocessor (continued)
    –   Since the 386DX, Intel Microprocessors support
        three modes:
            Real mode
            286 protected mode
            386 protected mode
What’s Contained in and
Attached to a Microcomputer?

   Microprocessor (continued)
    –   Real mode
            Intel processors power up in this mode
            Total address space = 1MB
            640KB limit for OS and application
            Single-tasking
What’s Contained in and
Attached to a Microcomputer?

   Microprocessor (continued)
    –   286 protected mode
            Total address space = 16 MB
            Can multitask certain applications
            Does not support virtual machines
What’s Contained in and
Attached to a Microcomputer?

   Microprocessor (continued)
    –   386 protected mode
            Total address space = 4GB
            Supports the use of virtual machines
            Multitasking
What’s Contained in and
Attached to a Microcomputer?

   Microprocessor (continued)
    –   Processors can work with 8-bit, 16-bit, 32-bit,
        and 64-bit chunks of data
    –   The number of bits (binary digits) is the size
        of data that can be processed at one time
What’s Contained in and
Attached to a Microcomputer?

   Motherboard and Chipset
    –   Motherboard – central circuit board
    –   Contains one or more CPU slots or sockets into
        which the processor is plugged
    –   Chipset, memory slots, voltage regulator module
        (VRM), ROM BIOS, and the expansion bus slots
        are components of a motherboard
    –   Chipset controls the flow of signals to and from
        the processor and other components
What’s Contained in and
Attached to a Microcomputer?

   Memory
    –   Chips that store programs and data
    –   Random-access memory (RAM)
    –   Read-only memory (ROM)
What’s Contained in and
Attached to a Microcomputer?

   Memory (continued)
    –   RAM
           System, main, or physical memory
           Used by active programs
           One or more circuit cards with memory chips
           Volatile – all is lost when the computer is powered
            off
What’s Contained in and
Attached to a Microcomputer?

   Memory (continued)
    –   ROM BIOS
            Stores programs permanently
            Called ‘firmware’ since it is non-volatile
    –   ROM BIOS contains:
            Code for starting the computer
            Code for controlling communications between
             the processor and other components
            A setup program for configuring system options
            Configuration information stored in a special kind
             of non-volatile RAM called the CMOS RAM
What’s Contained in and
Attached to a Microcomputer?

   ROM BIOS configuration information
    –   Disk drive types and capacity
    –   Disk boot order
    –   System memory
    –   Connectors (ports)
    –   Power management
    –   Other information determined by
        motherboard and ROM BIOS manufacturers
What’s Contained in and
Attached to a Microcomputer?

   Video Adapter and Display
    –   Video adapter – circuitry that sends the controlling
        output signals to the display screen
    –   Display screen – a monitor or a flat panel display
        (FPD) for visual output from the computer
What’s Contained in and
Attached to a Microcomputer?

   Keyboard
    –   An input device with a typewriter style layout
        of alphanumeric and punctuation keys
    –   Includes additional function, control, arrow,
        and editing keys
What’s Contained in and
Attached to a Microcomputer?

   Pointing Device
    –   Required to move a graphical pointer (cursor)
        around in a GUI
    –   Mouse is the most common pointing device –
        connects via a physical cable or a wireless
        connection.
    –   Other pointing devices: touch pad, track ball,
        joystick, and light pen
What’s Contained in and
Attached to a Microcomputer?

   Disk Drives
    –   Store data and programs
    –   Encoded on surface of small spinning platters
    –   Magnetic or optical technology
    –   Floppy drives and hard disk drives use magnetic
        technology
    –   Compact disk (CD) and digital versatile disk
        (DVD) drives use optical technologies
What’s Contained in and
Attached to a Microcomputer?

   Peripheral Devices
    –   Broad term for nonessential add-on devices
    –   Includes printers, scanners, pointing devices,
        digital cameras, external modems, and disk
        drives
Purpose, Types, and Functions
of Microcomputer Operating Systems


   What is an Operating System?
    –   An Operating System is:
            The central control program for a computer
            The intermediary between applications &
             hardware
Purpose, Types, and Functions
of Microcomputer Operating Systems


   Operating System Functions
    –   User interface
    –   Job management
    –   Task management
    –   Memory Management
    –   File management
    –   Device management
    –   Security
Purpose, Types, and Functions
of Microcomputer Operating Systems

   User Interface
    –   AKA the ‘shell’
    –   A software layer for user interaction
    –   Includes the command processor
    –   Includes the visual components of the OS
            Character-based command line
            GUI
Purpose, Types, and Functions
of Microcomputer Operating Systems

   Job management
    –   Controls the order and time in which
        programs are run
   Task management
    –   Found in multitasking operating systems
    –   Controls the focus
    –   Allows user to switch between tasks
Purpose, Types, and Functions
of Microcomputer Operating Systems

   Memory Management
    –   Manages placement of programs and data
        in memory
    –   Virtual memory manager moves code and
        data to virtual memory (file on hard drive)
Purpose, Types, and Functions
of Microcomputer Operating Systems

   File Management
    –   AKA data management
    –   Allows the OS to read, write, and modify data
    –   Data is organized into files
    –   Allows users to organize their files into
        containers called folders or directories
Purpose, Types, and Functions
of Microcomputer Operating Systems

   Device Management
    –   Controls hardware through device drivers
    –   A device driver is unique to a device
    –   Created by the manufacturer of the device to
        work with a specific operating system
Purpose, Types, and Functions
of Microcomputer Operating Systems

   Security
    –   Provides password-protected authentication
        of the user before allowing access
    –   Checks user name and password
    –   Restricts the actions that can be performed on
        a computer, customized for each user
Purpose, Types, and Functions
of Microcomputer Operating Systems

   Categories of Operating Systems
    –   Single-User/Single-tasking
    –   Single-User/Multitasking
    –   Multi-User/Multitasking
    –   Real-Time
Yesterday’s Operating Systems

   First the machines…
    –   Charles Babbage designed the first computer in
        the 1820s
    –   Apple II was the first microcomputer to combine
        critical elements like keyboard, monitor, operating
        system, and desirable and useful applications
Yesterday’s Operating Systems

   Then the Operating Systems
    –   Early single-purpose computers included
        system functions
    –   OSs did not exist as separate entity
    –   OSs evolved from need for multipurpose
        computers
Yesterday’s Operating Systems

   DOS, CP/M, Apple, and the Killer App
    – To be widely accepted a computer needed a
      ‘killer app’
    – VisiCalc was the killer app of 1970’s micro-
      computers
    – VisiCalc ran under the CP/M OS
    – VisiCalc contributed to the success of the
      Apple II
    – Both PC DOS and a version of CP/M were
      available for the IBM PC
Yesterday’s Operating Systems

   The Second Wave (second killer app)
    –   Lotus 1-2-3 – a DOS spreadsheet application
        that is fast and provides added functionalities
    –   Lotus 1-2-3 became the killer app for the
        IBM-PC/PC DOS combination.
Yesterday’s Operating Systems

   OS/2 (Operating System/2)
    –   Version 1.0 introduced in 1987
    –   Developed by Microsoft and IBM
    –   1.0 had costly memory and disk requirements
    –   IBM introduced OS/2 Warp in 1990’s
    –   IBM has ended development of new versions
Yesterday’s Operating Systems

   Microsoft Windows
    –   1985 first version – GUI on top of DOS
    –   Windows 3.0, introduced in 1990, provided better
        support for legacy DOS applications
    –   Windows 3.x works in real mode, standard mode,
        and 386 enhanced mode
    –   1992 Windows 3.1 successful with MS Office
Yesterday’s Operating Systems

   Windows for Workgroups
    –   DOS and earlier versions of Windows had no
        networking
    –   Windows for Workgroups 3.1 and 3.11 enabled
        peer-to-peer networking
Desktop OSs Available Today

    DOS from Microsoft      Windows 2000
    Windows NT              Windows XP
    Windows 98              Macintosh OSs
    Windows ME              UNIX
                             Linux
    Desktop OSs Available Today

   DOS from Microsoft
    –   DOS provides support for interaction with
        disk drives
    –   Microsoft’s first version of DOS, called PC
        DOS
    –   Introduced with the first IBM-PC in 1981
    –   Each major version of DOS supported new
        disk capacities
    –   DOS has a text-mode command line interface
Desktop OSs Available Today

   Windows NT
    –   First Microsoft OS to take full advantage of the
        capabilities of the Intel’s 386 protected mode
    –   Two main versions of NT – one for servers and
        another for desktop computers
    –   Windows NT 4.0, introduced in 1996, has a GUI
        similar to Windows 95
Desktop OSs Available Today

   Windows 98
    –   An evolutionary development compared to
        the earlier Windows operating system in
        terms of GUI and integrated components
    –   New options for customizing the GUI,
        including tighter integration with Microsoft’s
        Web browser, Internet Explorer (IE)
Desktop OSs Available Today

   Windows 98 (continued)
    –   Comes with drivers and support for devices
        like DVD drives
    –   It was the choice for PCs with plug and play
        (PnP) hardware, not supported by Windows NT
Desktop OSs Available Today

   Windows Me
    –   Introduced in 2000 as an upgrade to Windows 98
    –   Improved music, video, and home networking
        support
    –   Provides utilities as well as applications for
        dealing with PC software configuration, digital
        music, and video
Desktop OSs Available Today

   Windows 2000
    –   Family of OS products, introduced in 2000
    –   Combines the best of Windows 98 and
        Windows NT
    –   Windows 2000 Professional, Windows 2000
        Server, Windows 2000 Advanced Server, and
        Windows 2000 Enterprise Edition
Desktop OSs Available Today

   Windows XP
    –   Several products, but no server version
    –   Most common are Windows XP Home Edition
        and Windows XP Professional
    –   Improved GUI as well as several network- and
        security-related features
    –   Default desktop only contains the Recycle Bin
Windows Vista

   http://en.wikipedia.org/wiki/Windows_Vista
   What is a Wiki?
   Can we trust it?
Desktop OSs Available Today

   Macintosh Operating Systems
    –   Only run on Apple Macintosh computers
    –   Mac OS 9 and Mac OS X common today
Desktop OSs Available Today

   Macintosh Operating Systems (continued)
    –   Macintosh hardware and software are proprietary
        products of Apple Computer Company
    –   Macintosh computers generally use the PowerPC
        chip with an architecture that is enhanced for
        graphics and multimedia
Desktop OSs Available Today

   UNIX
    –   Introduced by Bell Labs Computing Science
        Research Center (Bell Labs) as UNIX Version 6
        in 1975
    –   A portable operating system for mini-computers
        and mainframe computers
    –   Supports timesharing and multi-user systems
    –   An excellent server operating system as it utilizes
        resources carefully, allowing only the required
        services to be loaded
Desktop OSs Available Today

   UNIX (continued)
    –   The current commercial versions of UNIX
        include Sun Microsystems’ Solaris, Hewlett-
        Packard’s HP-UX, IBM’s AIX, and Compaq’s
        Tru64 UNIX
    –   Many open source versions of UNIX are also
        available, which can be changed according to
        requirements
Desktop OSs Available Today

Linux
  –   Modeled on UNIX
  –   Named for original developer, Linus Benedict
      Torvalds
  –   Begun in 1991 by Torvalds and others as open-
      source for modern computers.
  –   Written in the C language using GNU C Compiler
      (GCC)
Desktop OSs Available Today

Linux (continued)
   –   Distributed free
   –   Vendors sell bundles with extras (utilities,
       GUIs, manuals)
   –   Novell, Red Hat, and others distribute such
       bundles
   –   Fastest-growing computer server OS
   –   Making inroads on desktop computers
Chapter Summary

Microcomputers Today
  –   A computer consists of hardware, applications
      software, and operating system software
  –   The operating system allows the user to interact
      with the computer hardware
Chapter Summary

Common Microcomputer Hardware
  –   The basic components of a microcomputer are
      processor, motherboard, memory, video adapter
      and display, keyboard, pointing device, disk
      drives, and peripheral devices
  –   You can identify hardware components by a
      visual inspection, by observing information
      displayed during the boot up process, and by
      accessing a ROM BIOS setup program
Chapter Summary

Purpose and Functions of Microcomputer
 Operating systems
  –   Certain functions are provided by most, if not
      all, current operating systems. These functions
      include a user interface, job management, task
      management, memory management, file manage-
      ment, device management, and security.
  –   The operating system makes everything work
      together
Chapter Summary

Purpose and Functions of Microcomputer
 Operating systems
  –   You can identify most of the functions provided
      by your operating system by careful observation.
      For instance, evidence of support of the security
      function includes a required logon procedure
      when you start your computer, and the need for
      authorization to access resources on your local
      computer.
Chapter Summary

Purpose and Functions of Microcomputer
 Operating systems
  –   There are four categories of operating systems:
          Single-User/single-tasking
          Single-User/multitasking
          Multi-User/multitasking
          Real-Time
  –   A Single-User/single-tasking operating system
      is one that allows only a single user to perform a
      single task at a time
Chapter Summary

Purpose and Functions of Microcomputer
 Operating systems
  –   An operating system that allows a single user to
      perform two or more functions at once is a Single-
      User/multitasking operating system
  –   A Multi-User/multitasking operating system is
      an operating system that allows multiple users to
      run programs simultaneously on a single network
      server, called a terminal server
Chapter Summary

Purpose and Functions of Microcomputer
 Operating systems
  –   Real-time operating systems are defined by
      their speed and ability to work with special
      real-time applications programs. A Real-time
      operating system is a very fast, relatively small
      OS that is often embedded, meaning it is built
      into the circuitry of a device and not normally
      loaded from a disk drive
Chapter Summary

Major Events in the Evolution of
 Microcomputer Operating Systems
  –   The history of current microcomputers and their
      OSs involved many technical advances and the
      imagination of a multitude of innovative people
  –   You can find many accounts of the history of
      computers and operating systems by searching
      the Internet
Chapter Summary

What OSs Are Available Today?
  –   The microcomputer operating systems common
      today include MS-DOS, several versions of
      Windows (Windows 98, Windows 2000, and
      Windows XP), Mac OS 9, Mac OS X, and several
      versions of UNIX and Linux
  –   Each of today’s common operating systems is
      best suited for certain uses
Chapter Summary

What OSs Are Available Today?
  –   Microsoft desktop OSs are common in the
      business environment
  –   Both UNIX and Linux can be found on high-
      end servers and on desktop computers. The use
      of Linux is growing on all types of systems
  –   The Mac OSs are commonly used in education
      and in graphic workstations