SYSTEM SOFTWARE
CSC402 Lecture 4
Computing Science Department
SINU
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Objectives
List the two major components of system software.
List the five basic functions of an operating system.
Explain why a computer needs an operating system.
Explain what happens when you turn on a computer.
List the three major types of user interfaces.
List the three categories of operating systems.
Discuss the strengths and weaknesses of the most
popular operating systems.
 List the system utilities that are considered to be
essential.
 Discuss data backup procedures.
 Understand troubleshooting techniques and determine
probable solutions to any operating system problems
you may encounter.
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SYSTEM COMPOSITION
USER
APPLICATION
SYSTEM
SOFTWARE
HARWARE
Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall
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System Software
• A software that enables the applications software to
interact with the computer and helps the computer
manage its internal and external resources.
• It is a collection of computer programs that manage the
resources of a computer and facilitate access to those
resources.
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System Software
o Starting the computer and transferring files from
the storage device to RAM memory.
o Managing programs that are active and on the
desktop and taskbar or running in the background.
o Managing memory (RAM) to optimize its use.
o Coordinating tasks including the communication
between input and output devices and programs.
o Providing a user interface to allow for easy and
seamless communication with the user.
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System Software
• Operating systems
• Principle component of System software
• Device drivers
• Help the computer control peripheral devices
• Utility programs
• Support, enhance, or expand existing programs
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System Software
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System Software
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Operating Systems
o Loads the OS into RAM
o Called booting
• Cold boot
o Start a computer that has not yet been
turned on.
• Warm boot
o Restarting a computer that has been turn
on.
o Important after installation of software or
computer crash or stop working.
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Operating Systems
o Involves six steps in cold or warm
boot)
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Operating Systems
o Step 1
• Load BIOS (Basic Input/Output System)
instructions into memory to allow computer to:
o Accept keyboard input.
o Show information on the monitor.
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Operating Systems
o Step 2
• Conduct the power-on self-test (POST) to
confirm that both the computer and its
peripheral devices are working properly. If any
part of the POST fails:
o A beep will sound.
o An error message will appear on the
monitor.
o The computer will stop.
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Operating Systems
• Step 3
o Load the operating system.
• BIOS looks for the operating system.
• BIOS loads into memory the kernel, the central part
of the operating system.
o Kernel (Supervisor) – manages the CPU
o Remains in main memory while the computer is
running, and directs other “non-resident”
programs to perform tasks that support
application programs.
• The operating system loads the system
configuration information.
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Operating Systems
o Step 4
• Check the system configuration.
o The registry, a database, stores information
about software and peripherals choices.
o The OS checks the configuration for drivers,
utility programs containing instructions for the
proper functioning of peripheral devices.
o The OS installs and loads needed drivers.
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Operating Systems
o Step 5
• Load system utilities, such as:
o Antivirus software
o Speaker volume control
o Step 6: Authenticate users.
• If necessary, enter an authentication/login, a user
name and password.
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Operating Systems
o Multitasking operating systems permit more than one
application to run at the same time.
• The foreground application is the active one.
• Background applications appear inactive.
o Preemptive multitasking ensures that all applications
have fair access to the CPU.
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Operating Systems
o A buffer, an area that holds data and instructions
temporarily, makes programs run faster.
o RAM memory functions as the buffer.
o The OS gives each program a portion of RAM
memory and keeps them from interfering with each
other.
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Operating Systems
o Virtual memory uses a portion of the hard disk
to extend RAM.
• Pages are units of fixed size and contain program
instructions and data.
• When RAM is full, copies of pages are temporarily
stored in a swap file, a special hard disk file.
• Transferring files between RAM and the hard disk is
called paging.
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Operating Systems
o Adding more RAM is often the best way to
improve computer performance because:
• Excessive of paging slows the computer and
called thrashing.
• Accessing data from the hard disk is slower than
accessing it from RAM.
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Operating Systems
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Operating System
• Device drivers enable communication between
the computer and the devices.
• Interrupts, signals created by input and output
devices, notify the OS when actions are taken.
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Operating System
• The user interface allows the user to:
• Start application programs
• Manage storage devices
• Safely shut down the computer
Graphical Interface
Menu Driven
Interface
Command-line-driven Interface
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Operating System
• The graphical user interface (GUI) uses icons, which
are small images that:
• Represent computer resources used to initiate
actions
• Appear on the desktop, the work area created
after the OS loads into memory
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Operating System
• The menu-driven user interface:
• Provides text-based menus
• Displays available user options
• The command-line user interface:
• Requires the user to type commands to instruct
the OS to perform the desired actions
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Operating System
Operating Systems
Market Share
Android
43.06%
Windows
29.39%
iPhone OSX
77.35%
Mac OSX
5.81%
Unknown
2.03%
Linux
1.11%
Source: https://gs.statcounter.com/os-market-share
• Android OS is the most popular operating system followed
by Windows.
• Several iterations
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Operating System
• Windows 11 – Most recent version
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Operating System
 Microsoft Windows 7
Feature
Versions
Home Premium
Professional
Ultimate
Improved desktop navigation including Windows Touch, a
feature that enables touch screen input
X
X
X
Starts programs faster; finds documents quicker
X
X
X
Web experiences are faster, easier, and safer
X
X
X
Watch, pause, and re-wind TV on your PC
X
X
X
Create a home network with HomeGroup
X
X
X
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Operating System
 Microsoft Windows 7 cont…
Feature
Create a home network with HomeGroup
Run Windows XP productivity programs in XP Mode
Connect to company networks easier and with more security with
Domain Join
Back up to a home or business network
Protect data on your PC and portable storage devices against loss or
theft with BitLocker
Work in the language of your choice and switch between any of 35
languages
Versions
Home Premium
Professional
Ultimate
X
X
X
X
X
X
X
X
X
X
X
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Operating System
• Microsoft Windows Vista
o Has translucent windows, three-dimensional
animation, and live taskbar thumbnails
o Supports tablet PCs and other mobile devices
o Has new and improved features such as:
• Search
• Networking tools
• Integrated speech recognition
• Gadgets—applications that appear as icons
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Operating System
• Microsoft Windows Server 2008
o Used in corporate environments to support
client/server systems
o Benefits include:
• Security
• Web server
• Administration
• Virtualization
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Operating System
• Microsoft Windows Mobile
o Designed for smartphones and PDAs
o Includes simplified versions of Windows
programs
o Supports synchronizing with corresponding
programs on desktop computers
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Operating System
• Mac OS
o Used on Macintosh personal computers
o Stable and simple to use
o Latest version is Mac OS X Snow Leopard
• UNIX
o Features preemptive multitasking
o Has many versions that are not compatible
o Hard to use
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Operating System
• Linux
o Is an open source software, meaning the source
code is available to users
o Powerful and free
o Gaining acceptance for Web servers
• Embedded operating systems
o Used in cell phones, kitchen appliances, etc.
o Include Windows CE and Symbian OS
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Operating System
• MS-DOS (DOS)
o Short for Microsoft disk operating system
o A command-line user interface OS
• PC versus Mac versus Linux
o A platform is the chip and operating system.
o PCs dominate.
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System Utilities:
• System utilities (utility programs)
o Software programs that are essential to
effective management of the computer
system
o Perform tasks such as:
• Backing up files
• Providing antivirus protection
• Compressing files
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System Utilities:
• Backup software copies data found on the hard
disk to a backup device.
• Full backups include all files and data.
• Incremental backups include only those files
changed or added since the previous
backup.
o Drive imaging software creates a mirror image of
the entire hard drive.
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System Utilities:
• Antivirus software protects
the computer from viruses.
• Popular antivirus programs:
o Norton AntiVirus
o McAfee VirusScan Plus
o AVG
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System Utilities:
• Searching for and managing files
o File manager is the utility software that
organizes and manages data.
• Copy files
• Determine how and where files are stored
• Delete files
o A search utility enables you to locate files.
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System Utilities:
• Scanning and defragmenting disks
o Disk scanning programs find and resolve disk
file storage problems.
o Disk cleanup utilities remove unnecessary files
to save space.
o Disk defragmentation programs reorganize
stored data in a more efficient manner.
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System Utilities:
• File compression utilities
o Decrease the size of files,
resulting in faster
downloads
o Create archives by storing
files in a special format
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System Utilities:
• Systems Update
o Windows Update for
Windows 7 and Vista
automatically
downloads and installs
updates.
o It includes service
packs, version
upgrades, and
security updates.
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System Utilities:
• Troubleshooting
o Keep a boot disk (emergency disk) to load
the operating system during times of
emergency.
o Use the Windows Help and Support utility.
o Shut down the system properly.
• Use correct procedure; don’t just turn the
power off.
• Put in sleep mode, a lower-power state, as an
alternative.
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Questions & Answers
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