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Chapter 2
Operating Systems: Software in
the Background
1
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What is an Operating System?
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Set of programs between application software
and hardware
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Operating System Definitions
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Kernel – main program
Booting
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Functions of an Operating
System
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Manage computer’s resources
User interface
Services for application software
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Basics of a Personal Computer
Operating System
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Platform
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Operating system
Hardware
Application software is platform specific
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Comparing User Interfaces
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Command line
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Text based
User must memorize commands
Graphical user interface
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Icons
Mouse
Nothing to memorize
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Home/Consumer Market
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Windows 95 and Windows 98
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Plug and Play
Object Linking and Embedding (OLE)
Long file names
Internet browsing
DVD
Wizards
Utilities
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Home/Consumer Market
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Windows Me
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More multimedia support
Restores system files
Automatic updates
Home network wizard
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Corporate Market
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Windows NT
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Network environment
Stronger security features
NT workstation and NT server
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Corporate Market
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Windows 2000
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Windows NT and Windows 98
Personalized preferences
Windows 2000 Professional and Windows
2000 Server
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Windows XP
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Extends Windows Me
More stable environment
Network Server
Desktop Computer
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Professional Client
Personal Client
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Windows CE
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Subset of Windows
Embedded Systems
Pocket computers
Internet connectivity
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Other Operating Systems
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Mac OS
UNIX
LINUX
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Network Operating Systems
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Sharing of resources
Data security
Troubleshooting
Administrative control
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Operating Systems for Large
Computers
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Mainframes
Used by many people at once
Several programs in memory
Special problems
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Sharing the CPU
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Multiprocessing
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Multiple CPUs
Each CPU with one program
Programs run simultaneously
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Sharing the CPU
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Multiprogramming
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Multiple programs
Programs run concurrently
Event-driven
Interrupts
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Sharing the CPU
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Time-sharing
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Multiple users
Time-driven
Time slice
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Memory management
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Partitions or regions
Foreground
Background
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Memory Management
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Virtual storage
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Paging
Page table
Thrashing
Memory protection
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Resource Allocation
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Sharing storage resources
Sharing printing resources
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Spooling
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Utility programs
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File manager
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allows you to view directories
allows copy, move, rename, delete, etc.
Windows Explorer
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Utility programs
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Device drivers
Backup and restore
File compression
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WinZip
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Utility programs
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Defragmenter