Transcript System Software

System Software
Chapter 4 of Computers:
Understanding Technology (Third
edition)
September 16, 2009 - William
Pegram
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System Software in Context
• Hardware
– Input (Ch. 2)
– Processing (Ch. 2)
– Output (Ch. 3)
– Storage (Ch. 3)
• Software
– System software(Ch. 4)
– Application software (Ch. 5)
September 16, 2009 - William
Pegram
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System Software
• Operating Systems
• Utility Programs
• Language Translators – Compiler,
Interpreter
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Pegram
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Operating Systems
• When computer is started, part of
operating system is loaded into random
access memory (RAM) from the boot drive
(typically the hard drive)
• Functions of operating system
– Managing main memory
– Controlling peripheral devices
– Managing file operations
– Monitoring system performance
– Providing user interface
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Operating System Functions
• Output buffers – selected areas of RAM which hold data
waiting to be transferred to an output device – This frees
the CPU to move on to something else; output device
will often be slower – print spooling is example
• Multitasking – User can work on more than 1 application
at the same time
• Drivers – programs that allow the operating system to
communicate with a peripheral device – the driver is
often specific to a specific device, manufacturer and
model number; typically this means that the application
program need only know how to communicate with
Windows and not with each peripheral device
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Pegram
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Operating System Functions (cont.)
• Security features
– Operating system can force user to enter a
correct username and password to access the
computer
– Windows XP and Windows Vista can provide
multiple user accounts on a single machine
and different levels of privileges among the
accounts
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User Interfaces
• Command line – e.g. DOS
• Graphical User Interface (GUI) – e.g.
Windows
• Graphical user interface was used in the
Alto computer developed by Xerox Palo
Alto Research Center, and later used in
the Apple Lisa and Macintosh computers
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Pegram
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Elements of GUI
• On-Screen desktop with graphical elements
displayed – icons, buttons, etc.
• Display windows – title bar, scroll bar, and other
common features
• Menus with drop down menus
• Toolbars with icons
• Dialog boxes to provide information and prompt
responses – tabs, radio buttons, checkboxes,
text boxes, OK/cancel buttons
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Pegram
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Personal Computer Operating
Systems
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Windows XP (ITN 114)
Windows Vista
Macintosh
IBM OS/2
Linux (ITN 170, ITN 270)
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Server Operating Systems
• Some operating systems are used with
networks, allowing multiple users to
connect to the server
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Server Operating Systems
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Novell NetWare
Windows NT Server
Windows 2000 Server (ITN 111)
Windows 2003 Server (ITN 115)
Windows 2008 Server
Unix (ITN 171 and ITN 271)
Linux (ITN 170 and ITN 270)
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Wireless Device Operating
Systems
• Palm OS
• Windows Mobile
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Pegram
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Utility Programs
• Antivirus – Norton, Symantec, McAfee
• Firewalls – security system that acts as
boundary to protect computer or network
• Diagnostic
• Uninstaller – remove all files associated with a
program
• Disk scanner – identify bad sectors
• Disk defragmenters
• File compression – WinZip, PKZIP, and Stuffit
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Utility programs (cont.)
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Backup
Disk toolkits – fix problems with a disk
Spam blocker
Anti-spyware – Windows Defender
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Pegram
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Language Translators
• Programmers generally write programs in
high-level languages – Java, COBOL,
Fortran
• Compilers translates entire program into
machine language file; that file is then
executed whenever program is run
• Interpreter translates one statement at a
time without producing a file, so repeated
runs require interpreter each time
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Pegram
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