A+ Guide to Managing and Maintaining Your PC
You Will Learn… z
About operating systems, what they are, and what they do
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How an OS interfaces with users, applications, and hardware
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How system resources help hardware and software communicate
Fifth Edition
Chapter 2
How Hardware and Software Work Together
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
Introducing Operating Systems
OS as a Middleman
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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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The Shell and the Kernel
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Common Operating Systems z z z
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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
How an OS Provides a User Interface
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Provides user interface
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Command-driven interfaces
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Stores, retrieves, and manipulates files and folders
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Menu-driven interfaces
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Icon-driven interfaces
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Manages applications
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Manages hardware
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Tracks, Sectors, and Clusters
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How an OS Manages Files and Folders
A Menu-Driven Interface
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
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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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Files and Directories
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How an OS Manages Applications
Partitions and Logical Drives
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Loading Application Software Using the Windows Desktop z
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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CPU processes 16 bits of data at one time
Software has “real” access to hardware
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Manages data in memory and in secondary storage
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Performs other background tasks
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
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CPU processes 32 bits of data at one time
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 software
Written for Windows 3.x
Accesses data 16 bits at a time
Programs should not infringe on resources of other programs that are running
Protected (32-bit) operating mode
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16-Bit and 32-Bit Software
Real (16-bit) operating mode
Provides access to hardware resources
Using a Shortcut Icon to Load Software
Real and Protected Operating Modes z
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32-bit software
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Written for Windows 95 and later Windows OSs
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How an OS Manages Hardware z
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 Uses Device Drivers to Manage Hardware z
Device drivers provide OS with software necessary to control devices
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16-bit read-mode drivers
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How an OS Manages Hardware (continued)
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How an OS Uses System BIOS to Manage Devices z
To communicate with simple devices (eg, floppy drives or keyboards)
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To access the hard drive
Supported by Windows 95/98
32-bit protected-mode drivers
Supported by Windows 95/98, Windows Me, and Windows NT/2000/XP
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Using System BIOS
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Using System BIOS (continued)
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4
System Resources
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
System Resources (continued)
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System Bus Components
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
Depend on certain lines on a bus on motherboard
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System bus components
Data bus carries data
Address bus communicates addresses (memory addresses and I/O addresses)
Control bus controls communication (IRQs and DMA channels)
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Interrupt Request Number (IRQ)
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Common Assignments for First Eight IRQs
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
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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
Early motherboards: eight IRQs
Second group of IRQs and second interrupt controller have been added to accommodate need for more devices
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Second IRQ Controller
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Viewing IRQ Assignments (continued)
Viewing IRQ Assignments z
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)
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
A+ Guide to Managing and Maintaining Your PC, Fifth Edition
Memory Addresses
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Memory Addresses (continued)
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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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I/O Addresses z
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Numbers CPU can use to access hardware devices
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Common Assignments for I/O Addresses
I/O Addresses (continued)
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Direct Memory Access (DMA) Channels z
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DMA Channels
Shortcut method that lets an I/O device send data directly to memory, bypassing the CPU
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OS Tools to Examine a System z
Device Manager
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System Information utility
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Microsoft Diagnostic Utility (MSD)
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Device Manager z
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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)
System Information Utility z
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Using Windows System Information
BIOS version in use
Directory where OS is installed
How system resources are used
Information about drivers and their status
Additional information about software 44
Microsoft Diagnostic Utility (MSD)
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Using MSD
Useful for viewing information about the system, including:
Memory
Video
Ports
Device drivers
System resources
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Summary z
How hardware and software work together
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Different operating systems
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A+ Guide to Managing and Maintaining Your PC, Fifth Edition
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Gives similar, but more, information than Device Manager
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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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