System Software

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System Software

• Chapter 4
• The Power behind the Power

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Chapter 4 Key Questions

• 4.1 What are the three components of system
  software?
• 4.2 What are the principal functions of the
  operating system?
• 4.3 What are some common desktop, network, and
  portable OSs?
• 4.4 What are the characteristics of device
  drivers and utility programs?

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Three Components of System Software
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Three components of system Software

• Operating Systems
• Manage system resources CPU, memory, I/O
• Control and monitor the execution of other
  programs
• Device Drivers
• Programs that are used to control peripheral
  devices
• Utility Programs
• Support and enhance existing programs
• File backup, disk de-fragmentation, etc.

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Operating System What It Does

• Booting
• process of loading an operating system into a
  computers memory
• CPU(memory) management
• the supervisor(kernel) remains in memory
• It directs other nonresident, programs
• Virtual memory use hard disk as a logical
  extension of memory

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Operating System What It Does

• File management
• File a program or data (audio, video, text)
• OS manages files on hard disks and other storages
  devices like CD-ROM, DVD, etc
• Provides file-related operations
• Create, delete, copy, rename,
• folders (directories) for file management
• NOTE use folders to organize your files

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Operating System What It Does

• Task Management
• Multitasking
• the execution of two or more programs by one user
  concurrently on the same computer with one
  central processor
• Multiprogramming
• the execution of two or more programs
  concurrently on a multiuser operating system
• Time-sharing
• a single computer processes the tasks of several
  users in round-robin fashion
• Multiprocessing
• processing done by two or more computers or
  processors linked together to perform work
  simultaneously

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Operating System What It Does

• Formatting
• Prepare a disk (floppy disk, or hard disk) for
  store data and/or programs.
• Each disk must be formatted before it can be
  used,
• Hard disks formatted by the manufacture,
  normally not done by end users
• Floppy disks formatted by the manufacture or by
  end users

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Different Operating Systems

• DOS
• Mac OS
• Windows 3.1, 95, 98, Me
• Network platforms
• Netware
• Windows NT/2000
• Unix/Solaris
• Unix/Linux/FreeBSD
• Palm OS
• Windows CE/Pocket PC

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Device Drivers

• Device drivers
• Programs that are designed to control input and
  output devices
• Three components for I/O devices
• Device itself (scanner) - hardware
• Device controller (parallel card) - hardware
• Device driver designed for the OS -software
• Normally it is on a CD-ROM or a floppy disk

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Utility Programs

• Utility programs
• Backup duplicate copy of data on your hard disk
• Data recovery used to restore data that has
  been physically damaged or corrupted
• Virus protection
• Antivirus software program that scans hard
  disks, floppy disks, and memory to detect viruses
• Data compression utilities Compress the data so
  that less space is required to store or transmit
  data
• File defragmentation reorganize files on your
  hard disk for better performance