a+ guide to managing and maintaining your pc, 6e chapter 2 introducing operating systems (v0.92)

A+ Guide to Managing and Maintaining your PC, 6e

Chapter 2Introducing Operating Systems (v0.92)

A+ Guide to Managing and Maintaining your PC, 6e 2

Introduction

• A computer comprises hardware and software– Physical devices are the visible

component– The controlling software component is

not visible


Operating Systems Overview

• The OS can be analogized to a “middleman”– Between the hardware and the

applications software

• A computer needs only one operating system

• Operating systems have evolved to a very large and complex software system


Basic Function of an OS

• Manages hardware

• Runs applications

• Provides an interface for users

• Retrieves and manipulates files


Figure 2-1 Users and applications depend on the OS to relate to all applications and hardware components


Overview of OS Types


DOS (Disk Operating System)

• The first OS used by IBM PC computers and compatibles

• Where DOS can still be found:– Specialized systems using older applications– On troubleshooting disks or CDs

• Windows 3.x and DOS– Windows 3.x provided a graphical interface– Underlying OS functions were performed by DOS


Figure 2-3 Windows 3.x was layered between DOS and the user and applications to provide a graphics interface for the user and a multitasking environment for applications


DOS Still Lives!

• Windows 9x/Me uses DOS in the underlying OS

• Windows XP/2000 run DOS emulation programs

• Command prompt mode of NT/2000/XP/Vista

• Recovery Console– 2000/XP/Vista


Windows 9x/Me

• Refers to Windows 95, Windows 98, Windows Me

• Combine a DOS core with graphical user interface

• Designed to bridge legacy and newer technologies– Backward-compatible with older systems– Able to accommodate new technologies


Figure 2-5 Windows 9x/Me is the bridge from DOS to Windows NT


Windows NT

• Two versions of Windows NT (New Technology):– Windows NT Workstation for desktops– Windows NT Server to control a network

• Best known feature: new OS core replacing DOS

• Completely new file storage system (NTFS)


Windows 2000

• Upgrades Windows NT 4.0

• Improvements over Windows NT:– A more stable environment– Support for Plug and Play– Device Manager, Recovery Console, Active Directory– Better network support– Features specifically targeting notebook computers


Windows XP

• Integrates Windows 9x/Me and Windows 2000

• Two main versions: Home Edition and Professional

• Noteworthy new features:– Allows two users to logon and open applications– Incorporates Windows Messenger and Media Player– Adds advanced security, such as Windows Firewall


Windows XP Requirements

• Installation requirements– 64 MB RAM (128 MB recommended)– 1.5 GB free hard drive space (2 GB

recommended)– 233-MHz CPU speed (300-MHz

recommended)


Figure 2-8 The Windows XP desktop and Start menu


Windows Vista

• Newest Windows OS• (4) versions• Noteworthy new features:

– New graphical interface– Revamped engine– A new interface between it and applications– New security features– DirectX 10 (games & multimedia)


Vista Issues

• Hefty hardware requirements• Limited support for older hardware• Little hardware support for DirectX 10• Software compatibility problems• Performance• First edition issues

– SP1 released early 2008


Windows Server 2003

• Refers to a suite of Microsoft operating systems: – Windows Small Business Server 2003– Storage Server 2003– Server 2003 Web Edition– Server 2003 Standard Edition– Server 2003 Enterprise Edition– Server 2003 Datacenter Edition


UNIX

• Comprises a class of operating systems

• UNIX versions referred to as flavors or distributions

• Chief uses:– Controlling networks– Supporting Internet-based applications


Linux

• Variation on UNIX created by Linus Torvalds• OS kernel and source code are freely distributed• Popular distributions:

– SuSE (www.novell.com/linux/suse)– RedHat (www.redhat.com) – Ubuntu

• Used as both a server and a desktop • X Windows: GUI shells for UNIX and Linux

http://www.novell.com/linux/suse

http://www.redhat.com/


OS/2

• Jointly developed by IBM and Microsoft

• Chiefly used in certain types of networks

• Part of OS/2 was incorporated into Windows NT


Mac OS

• First introduced in 1984 with Macintosh computers

• Current version: Mac OS X (ten)

• Mac OS X can work on some Intel-based computers

• Markets: education, desktop publishing, graphics

• Noteworthy features:– Support for graphics and multimedia capabilities – Use of the Finder program to provide the desktop– Superior Plug and Play capabilities– Excellent support for multitasking


Figure 2-10 The Mac OS X desktop is intuitive and easy to use


Operating System Components and Functions


Operating System Components

• Components common to all OS’s– Kernel– Shell– Registry database and/or initialization

files


OS Component Descriptions

• The shell exposes functions to users and applications– Graphical or command prompt

• The kernel (core) interacts with hardware devices– Example: passes a print request to a printer device

• Registry database and initialization files – Store configuration information in Windows


Figure 2-11 Inside an operating system, different components perform various functions


Basic Operating System Functions

• Manages hardware

• Runs applications

• Provides an interface for users

• Retrieves and manipulates files


An OS Provides a User Interface

• Sequence of events occurring after PC is turned on– The operating system is loaded– Running OS provides an interface (desktop)– OS awaits an event, such as a double-click

• A user can initiate an event in several ways:– Click a menu item – Enter a command in Run dialog or command console – Double-click an icon


Operating System User Interfaces

• Command prompt

• GUI (Graphical User Interface– Menu– Icon


Figure 2-12 Enter command lines in a Command Prompt window


Figure 2-13 A menu-driven interface: Windows Explorer in Windows XP


An OS Manages Files and Folders

• File system: organizes files and folders

• File systems used by Windows for hard drives:– File Allocation Table (FAT): tracks disk

space usage– New Technology File System (NTFS):

replacing FAT


Storage Device Structure

• Organization of a hard drive or floppy disk– Platter contains concentric tracks– Track contains 512 byte sectors– Cluster contains one or more sectors– Cluster is the smallest unit on disk for

storing a file


Figure 2-14 A hard drive or floppy disk is divided into tracks and sectors; several sectors make one cluster


Files and Directories

• File system hierarchy:– Directories (called folders in Windows)– Subdirectories (child directories) – Files


Files and Directories (continued)

• Directories can contain subdirectories and files

• Directory table: lists subdirectories and files

• Root directory: directory for a logical drive; e.g., C:\

• Path: drive, directories, filename, and file extension– Example: C:\wp\data\myfile.txt points to

“myfile”


Figure 2-15 A hard drive is organized into directories and subdirectories that contain files


Partitions and Logical Drives on a Hard Drive

• Hard drives are organized into partitions

• Two types of partitions– Primary: can only have one logical drive; e.g.,

C:\• Can be bootable

– Extended: can have one or more logical drives


Hard Disk Partitions

• Logical drive (sometimes called a volume) – Formatted using a file system– Has a root directory and subdirectories

• Disk Management tool– Used to create/view partitions, format logical

drives


Figure 2-18 Use the Windows 2000/XP Disk Management utility to see how a hard drive is partitioned


An OS Manages Applications

• The OS installs and runs all other PC software

• Application: software providing services for users

• Applications rely on the OS for support operations– Example: MS word relies on OS to manage memory

• Applications are typically tailored to a single OS– Ensure that OS is suitable for a given application


Installing Application Software

• Sources of application software:– Internet, CDs, DVDs, or floppy disks

(obsolete)

• Installation program is provided by application


Installation Program Tasks

• Folders are created on the hard drive

• Files are copied to the folders

• For Windows, entries are made in Windows registry

• Icons are usually placed on desktop

• For Windows, entries are added to the Start menu


Launching Application Software Using the Windows Desktop

• An application has to be started before use– You run, load, launch, or execute the application

• Four ways to run software: – Use a shortcut icon– Use the Start menu– Use the Run command– Use Windows Explorer or My Computer


Real (16-bit), Protected (32-bit), and Long (64-bit) Operating Modes

• Bit type: number of bits simultaneously processed

• Real (16-bit) mode– Exposes hardware to application (no longer used)– Example: DOS

• Protected (32-bit) and Long (64-bit) modes– OS controls how an application accesses hardware– Preemptive multitasking is supported – Example: Windows XP Professional x64 Edition


16-bit, 32-bit, and 64-bit Software

• 16-bit software – Written for Windows 3.x– Data access is 16 bits at a time

• 32-bit programs – Written for Windows NT/2000/XP and Windows 9x/Me

• 64-bit programs– Written for Windows XP Professional x64 Edition

• Most software today is mostly 32-bit


An OS Manages Hardware

• OS interacts with hardware using drivers or BIOS

• Software falls into three categories:– Device drivers or the BIOS– Operating system– Application software


Figure 2-23 An OS relates to hardware by way of BIOS and device drivers


How an OS Uses Device Drivers to Manage Devices

• Device drivers: specify how to interact with a device– Example: a driver links a computer to a digital camera

• Drivers are provided by OS and device manufacturer

• Three kinds of drivers (corresponds to a mode)– 16-bit real, 32-bit protected, and 64-bit long

• Device drivers in Windows– Before installation, verify Microsoft has tested device– Registry stores information about 32-bit device drivers– Updated drivers are available at manufacturer’s site


Device Drivers in Windows

• Before installation, verify Microsoft has tested device– Windows XP/Vista use signed drivers

• Registry stores information about 32-bit device drivers

• Updated drivers are available at manufacturer’s site


How an OS Uses System BIOS to Manage Devices

• System BIOS contains device information – Instructions enable CPU to communicate with device– Example: keyboard activated at startup using BIOS

• Configure BIOS device interaction in CMOS setup

• The OS may use system BIOS to access devices

• Disadvantage of using BIOS device management– BIOS does not operate as fast as device drivers


How an OS Manages Memory

• Memory functions performed by OS at startup– Launches utilities to manage memory– Assigns addresses to each location of memory

• Drivers, OS, and application use memory addresses– Enables three software layers to refer to shared

data


OS Memory Access

• 16-bit applications program in real mode has direct access to RAM – Example: Under DOS

• The OS controls memory access in protected mode– The address spaces of a program is protected – Virtual memory expands number of running

programs– Examples: Windows 2000/XP/Vista


Figure 2-27 Protected mode allows more than one program to run, each protected from the other by the operating system


OS Tools to Examine a System

• A variety of tools are available:– The Windows Desktop– My Computer and Windows Explorer– System Properties– Control Panel – Device Manager– System Information– Windows Help and the Microsoft Web Site


The Windows Desktop

• Primary tool provided by the Windows shell

• Terms associated with the desktop– Taskbar: displays information, offers program access– Service: support program running in the background– System tray: displays icons for running services– Shortcut: desktop icon pointing to a program


Desktop Configuration Tools

• Display Properties Window

• The Taskbar and System Tray

• Shortcuts


Figure 2-28 The Windows XP desktop and Start menu


My Computer and Windows Explorer

• Used to manage files, folders, and other resources

• Tools share similar functionality

• Perform a wide range of tasks using shortcut menus – Example: create a new file

• File and folder operations performed with Explorer– Creating a folder– Deleting a folder– Changing file attributes– Changing folder options


Explorer File and Folder Operations

• Creating a folder

• Deleting a folder

• Changing file attributes

• Erasing a file

• Renaming a file

• Changing folder options


Figure 2-41 Create a new file using Windows Explorer


System Properties Utility

• Two ways to open the utility program:– Right-click My Computer and select

Properties– Click the System applet in the Control

Panel


System Properties Utility (continued)

• Some tasks that can be performed – View processor and memory information– Change the name of the computer on the network– Access Device Manager on the Hardware tab– Control performance on the Advanced tab– Switch System Restore on or off – Use the Automatic Update tab to control updating


Control Panel

• Contains applets used to manage the system

• Accessing Control Panel in Windows XP– Click Start and the click Control Panel

• Two views: Category View and Classic View

• Applets can be launched via the Run dialog box– Example: enter Main.cpl to open Mouse Properties


Device Manager

• Primary graphical tool for solving hardware problems

• Primary screen displays a list of devices– Right click Properties to view device details

• Symbols are used to indicate a device status– Example: red X over device indicates it is

disabled


Device Manager (continued)

• Some tasks that can be performed– Enable, disable, uninstall a device – Update device drivers– Uninstall device drivers


Figure 2-47 Windows XP Device Manager gives information about devices and allows you to uninstall a device


System Information

• Used to view detailed information about the system

• Important features – BIOS version you are using– The directory where the OS is installed– How system resources are used– Information about drivers and their status

• To open utility, enter Msinfo32.exe in Run dialog box


Windows Help and the Microsoft Web Site

• Key guide to system

• Excellent troubleshooting resource– Example: analyze problem with Internet connection

• Microsoft Web site: http://support.microsoft.com

• Use search engine to locate alternative resources– Ensure that the alternative site is reputable

http://support.microsoft.com/


Figure 2-51 Troubleshooter making a suggestion to resolve a problem with using the modem to connect to the Internet


Keystroke Shortcuts in the OS

• Simplify interaction with the operating system

• Examples– Function keys: F4, F5, F8– Text editing operations: Ctrl+C, Ctrl+V, Ctrl+x

• Shortcut keys are critical when mouse is not working


Summary

• The OS manages system resources for users and applications

• DOS (disk operating system): early command- driven OS

• Modern OSs: Windows 2000/XP, Linux, Mac OS X

• Operating systems are divided into a kernel and user shell

• Two OS running modes: real and protected


Summary (continued)

• OS functions: providing a user interface, managing files, managing applications, and managing hardware

• Windows desktop: primary graphical interface to OS

• Windows Explorer: used to navigate directory and manipulate files and folders

• Other tools: System Properties, Control Panel, Device Manager, System Information, and Windows Help

• Keystroke shortcuts provide a way to perform tasks without a mouse

a+ guide to managing and maintaining your pc, 6e chapter 2 introducing operating systems (v0.92)

Documents

windows firewalla guide

windows nta guide

applicationsa guide

dosa guide

recommendeda guide

filesa guide

windows mecombine

new technologiesa guide