Transcript 21324-8chapter02

A+ Guide to Managing
and Maintaining Your PC
Fifth Edition
Chapter 2
How Hardware and Software
Work Together
You Will Learn…

About operating systems, what they are, and
what they do

How an OS interfaces with users, applications,
and hardware

How system resources help hardware and
software communicate
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Introducing Operating Systems
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Software that controls a computer
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Acts as a middleman between applications and
hardware
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Two main internal components

Shell

Kernel
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OS as a Middleman
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The Shell and the Kernel
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Common Operating Systems
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DOS
Windows 9x
Windows NT, Windows 2000, and
Windows XP
Unix
Linux
OS/2
Mac OS
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What an Operating System
Does

Provides user interface
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Stores, retrieves, and manipulates files and
folders
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Manages applications
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Manages hardware
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How an OS Provides a User
Interface
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Command-driven interfaces
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Menu-driven interfaces
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Icon-driven interfaces
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A Menu-Driven Interface
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How an OS Manages Files and
Folders
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Uses file system (FAT or NTFS) to track how
clusters are used for each stored file
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Uses directories, subdirectories, and files
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Uses partitions and logical drives on hard drive
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Tracks, Sectors, and Clusters
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Files and Directories
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Partitions and Logical Drives
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How an OS Manages
Applications
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Provides access to hardware resources
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Manages data in memory and in secondary
storage
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Performs other background tasks
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Loading Application Software
Using the Windows Desktop
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Shortcut icon
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Start menu
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Run command
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Windows Explorer or My Computer
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Using a Shortcut Icon to Load
Software
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Real and Protected Operating
Modes
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Real (16-bit) operating mode
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CPU processes 16 bits of data at one time
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Software has “real” access to hardware
Protected (32-bit) operating mode
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CPU processes 32 bits of data at one time
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More than one program can be running, each one
“protected” from others
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Uses preemptive multitasking
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16-Bit and 32-Bit Software
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16-bit software
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Written for Windows 3.x
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Accesses data 16 bits at a time
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Programs should not infringe on resources of other
programs that are running
32-bit software
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Written for Windows 95 and later Windows OSs
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How an OS Manages Hardware
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Uses device drivers or the BIOS (system
BIOS, startup BIOS, or CMOS setup) to
interface with hardware
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Trend is to manage devices with device drivers
rather than BIOS
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How an OS Manages Hardware
(continued)
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How an OS Uses Device
Drivers to Manage Hardware
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Device drivers provide OS with software
necessary to control devices
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16-bit read-mode drivers
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Supported by Windows 95/98
32-bit protected-mode drivers
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Supported by Windows 95/98, Windows Me, and
Windows NT/2000/XP
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How an OS Uses System BIOS
to Manage Devices
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To communicate with simple devices (eg,
floppy drives or keyboards)
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To access the hard drive
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Using System BIOS
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Using System BIOS (continued)
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System Resources
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System Resources (continued)
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Depend on certain lines on a bus on
motherboard
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System bus components
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Data bus carries data
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Address bus communicates addresses (memory
addresses and I/O addresses)
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Control bus controls communication (IRQs and
DMA channels)
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System Bus Components
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Interrupt Request Number (IRQ)
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Line on a bus that device needing service uses
to alert the CPU
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Managed by interrupt controller on
motherboard
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Early motherboards: eight IRQs
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Second group of IRQs and second interrupt
controller have been added to accommodate need
for more devices
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Common Assignments for First
Eight IRQs
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Second IRQ Controller
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Viewing IRQ Assignments
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Microsoft Diagnostic Utility (MSD) for DOS
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Device Manager for Windows 2000/XP and
Windows 9x
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Viewing IRQ Assignments
(continued)
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Viewing IRQ Assignments
(continued)
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Memory Addresses
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Hexadecimal numbers assigned to RAM and
ROM so the CPU can access both
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Used to access physical memory
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Often written in segment:offset form
(eg, C800:5)
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Memory Addresses (continued)
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I/O Addresses
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Numbers CPU can use to access hardware
devices
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I/O Addresses (continued)
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Common Assignments for I/O
Addresses
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Direct Memory Access (DMA)
Channels
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Shortcut method that lets an I/O device send
data directly to memory, bypassing the CPU
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DMA Channels
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OS Tools to Examine a System
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Device Manager
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System Information utility
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Microsoft Diagnostic Utility (MSD)
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Device Manager
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Primary tool used to manage hardware devices
under Windows 2000/XP and Windows 9x
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Device Manager ( continued)
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System Information Utility
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Gives similar, but more, information than
Device Manager
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BIOS version in use
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Directory where OS is installed
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How system resources are used
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Information about drivers and their status
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Additional information about software
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Using Windows System
Information
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Microsoft Diagnostic Utility
(MSD)
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Useful for viewing information about the
system, including:
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Memory
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Video
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Ports
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Device drivers
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System resources
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Using MSD
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Summary

How hardware and software work together
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Different operating systems

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What they do

How they work to control hardware devices
How an OS provides the interface that users
and applications need to command and use
hardware devices
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