Download Chapter 3 - Angelfire

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System Software
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Objectives
• By the end of this lecture, you should know
how to:
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– Describe the differences between system
software and application software.
– Discuss the three basic functions of any
operating system.
– Describe the three categories of operating
systems.
– Discuss the purpose of utilities and utility suites.
– Identify the five most essential utilities.
– Define device drivers.
– Discuss language translators.
Systems Software
• Background software that helps you
interact with the computer
• Designed to handle
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– Technical details
– Where programs stored
– How commands executed
– Where files saved
– How output handled
Four Kinds of Programs
• Operating system
• Utilities
• Device drivers
• Language translators
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Operating Systems
• Every operating system performs three basic
functions:
1. Resource management
• coordinate keyboard, mouse, printer, monitor, storage
devices, and memory.
2. Provide a user interface
• users interact with application programs and computer
hardware through a windows-like graphical user interface
(GUI) that use graphic objects called icons to represent
commonly used features.
3. Run applications
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• the OS loads and runs application programs, such as
word processors and spreadsheets, and support
multitasking, which is the ability to run more than one
application at a time.
Operating Systems
• Some widely used operating systems are:
• Windows
• Mac OS
• Unix
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Windows
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• Windows is the most popular
microcomputer operating system.
• Windows gets its name from its use of
rectangular boxes called windows.
• Over 80 percent of the market now uses
Windows.
• It is designed to run with Intel and Intel
compatible microprocessors such as
Pentium IV.
Windows
• Versions of Windows include
– Windows 95
– Windows 98
– Windows 2000
– Windows ME
– Windows XP
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Windows
• Multitasking - different programs running
simultaneously with this operating system.
• The user interface of Windows is called the desktop.
• The desktop has two views:
– Classic
– Web style – look and feel of Internet Explorer browser.
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• Windows and many other operating systems store
information in a system of files and folders.
• Files are used to store data and programs and are
stored on a secondary storage device such as the
hard disk.
• Related files are stored within a folder, and for
organization purposes, a folder can contain other
folders.
Windows
• The common way for users to interact with the
Windows operating system is by selecting
icons.
• The Start Menu of Windows displays a list of
commands used to:
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Gain access to information.
Change hardware settings.
Find information.
Get online help.
Run programs.
Log off a network.
Shut down the computer.
Mac OS
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Operating system designed to run only on
Macintosh computers.
It is a very powerful and easy to use
operating system and comes in a variety of
versions.
Its market share is much less than
Windows.
Mac OS includes several unique features:
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Sherlock - an innovative search feature for
locating information on the Web or hard drive.
Aqua – an intuitive user interface.
Dock – provides a flexible tool for organizing
files.
Unix
Linux
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Unix
The Unix operating system was originally designed
to run on minicomputers in network environments.
A powerful operating system for microcomputers
and servers on the Web.
One important version of Unix is called Linux.
Linux is not a proprietary operating system (it is not
owned and licensed by a company).
It was developed in 1991 by Linus Torvalds, a
graduate student at the University of Helsinki.
Torvalds provided the operating system free to
others.
Categories of OS
1. Embedded – hand-held
2. Network OS – linked computers
3. Stand-alone OS – desktop
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Categories of OS
• Embedded operating systems:
• Used for handheld computers and smaller
devices like PDAs.
• Completely stored within the device in its
ROM memory.
• Popular embedded operating systems
include Windows CE and Palm OS.
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Categories of OS
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Network operating systems (NOS):
• Used to control and coordinate computers
that are linked together.
• Typically located on one of the connected
computers hard disks.
• Called the network server, this computer
coordinates all communication between
linked computers.
• Popular network operating systems include
NetWare, Windows NT Server, Windows
XP Server, and UNIX.
Categories of OS
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Stand-alone operating systems
(desktop operating systems):
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Control a single desktop or notebook computers.
Located on the computer’s hard disk.
Often desktop computers and notebooks are part of
a network.
– The desktop operating system works with the
network’s NOS to share and coordinate resources.
– Referred to as the client operating system
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Popular desktop operating systems include
Windows, Mac OS, and some versions of UNIX.
Utilities
• Utilities are specialized programs designed
to assist users with tasks that will help run
their computers without problems.
• Most operating system programs provide
some utility programs.
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• More powerful utility programs can be
purchased.
Essential Utilities
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Troubleshooting
Antivirus
Uninstall
Backup
File compression
Utilities
• Troubleshooting
• programs that recognize and correct problems.
• Antivirus
• programs that guard your computer against viruses.
• Uninstall
• programs that allow you to remove unneeded programs
from your hard disk.
• Backup programs
• programs that make copies of your files.
• File compression programs
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• programs that reduce the size of files.
Windows Utilities
• Backup
– utility program that makes a copy of selected or all files
that have been saved onto a disk. It helps to protect you
from the effects of a disk failure.
• Disk cleanup
– troubleshooting utility that identifies and eliminates
nonessential files. This frees up valuable disk space
and improves system performance.
• Disk defragmenter
– utility program that locates and eliminates unnecessary
fragments and rearranges files and unused disk space
to optimize operations.
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• These utilities can be accessed from the Systems
Tools menu.
Utility Suites
• Several utility programs sold in a
package is called a utility suite.
• The cost of the utility suite package
is less than buying the programs
separately.
• Two best-known utility suites are:
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– McAfee Office.
– Norton System Works.
– DataFellows
Norton System Works
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Norton System Works includes a suite of
five separate program groups.
Each group can be purchased separately or
as part of the suite.
The five groups of Norton System Works
are:
1. Norton Utilities – a collection of 17 separate
trouble-shooting utilities.
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finding and fixing problems
improving system performance
preventing problems from occurring
troubleshooting other problems
Norton System Works
2. Norton AntiVirus – a collection of antivirus
programs.
– protection from over 21,000 different
viruses
– quarantine or delete existing viruses
– automatically update its virus list to check
for newest viruses
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Norton System Works
3. Norton CleanSweep – a collection of
programs to safely remove programs and
files.
– Archive, move, backup files
– Clean up your hard drive
– Protects existing files from damage
4. Norton CrashGuard – a collection of
trouble-shooting utilities.
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– automatically protects against programs
that crash or freeze the display screen
– provides options to recover your current
work before an event causes a crash or
freeze
Norton System Works
5. Norton Web Services – utilities to keep you
alert.
– monitors system for out-of-date software
– notifies you of available software updates
that can be installed from the Internet
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Device drivers
• Specialized programs
• Loaded into memory each time
• Add new device: install device driver
– Whenever a new device is added to the computer system,
a new device driver must be installed before the device can
be used.
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Device drivers
• Drivers work with the operating system to allow
communications between the device and the rest of
the computer system.
• Many times, device drivers are available directly
from the manufacturer’s Web site.
• Windows provides an Add/Remove Hardware
Wizard that offers step-by-step guidance for the
installation and removal of device drivers.
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Language translators
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• Language translators convert human-oriented
programming languages to machine language.
• Computers only understand a language
consisting of 0’s and 1’s called machine
language.
• To ease the burden of programming entirely in
0’s and 1’s, special programming languages
were develop that more closely approximate
human language.
• Language translators convert these
programming statements into the zeros and
ones that the computer is able to process.