Chapter 3 SAK3002 – Information Technology and Its Application SAK3002 – IT and Its Applications COMPUTER SOFTWARE 3 Chapte r
Dec 26, 2015
Chapter 3 SAK3002 – Information Technology and Its Application
SAK3002 – IT and Its Applications
COMPUTER SOFTWARECOMPUTER SOFTWARE
33ChapterChapter
Chapter 3 SAK3002 – Information Technology and Its Application
SAK3002 – IT and Its Applications
Objectives of this chapter:Objectives of this chapter:
Identify the types of system software
Identify the types of operating system
Describe the functions of an operating system
Identify utility programs
Explain the purpose of the utilities program
You can…
Chapter 3 SAK3002 – Information Technology and Its Application
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OverviewOverview
This chapter covers System Software
Operating System Utility Program
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Computer software is:
A group of programs that connects user with computer devices
Comprised of a sequence of instructions Designed to instruct the computer to execute
desired functions by the users
IntroductionIntroduction
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Introduction (cont’d)Introduction (cont’d)
Software Layers
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System SoftwareSystem Software What is system software?
Programs that Programs that maintain operation maintain operation
of computerof computer
OperatingOperating Systems Systems Utility ProgramsUtility Programs
Two categories
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3.1 Operating System
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A group of programs that organize and manage the whole computer operations
OS is a set of instructions that coordinate all the internal activities among computer hardware, application programs and users
Operating SystemOperating System What is an operating system?
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OS is controlled by the kernel. What is a kernel?
Kernel is the supervisor program that manage the memory and devices
Kernel is loaded into the memory from the hard disk (or other storage) during booting until computer is turned off
It is known as memory resident (because it resides in memory as long as the power is on. Non-resident are other programs that resides in hard disk at the same time)
Operating System (cont’d)Operating System (cont’d)
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The functions of an operating system
administer security
start the computer (Booting)
manage memory
monitor performance
control a network
provide a user interfacemanage programs
provide file management and other utilities
establish an Internet connection
schedule jobs and configure devices
Operating System (cont’d)Operating System (cont’d)
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Booting
Cold boot Turning on computer that has been powered off
Warm boot Restarting computer that is powered on
Process of starting or restarting a computer
Operating System (cont’d)Operating System (cont’d)
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A personal computer boot up process
Step 1. Power supply sends signal to com-ponents in system unit
Step 4. Results of POST are compared with data in CMOS chip
Step 2. Processor accesses BIOS to start computer
Step 3. BIOS runs tests, called the POST, to check components such as mouse, keyboard, and adapter cards
Step 5. BIOS looks for system files on a USB drive, in floppy disk drive or CD/DVD drive, and then hard disk
Step 6. Kernel (core) of operating system loads into RAM
Step 7. Operating system loads configuration information and displays desktop on screen
Operating System (cont’d)Operating System (cont’d)
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4 main functions of OS:Manage computer programsManage computer hardwareProvides user interfaceSupport application software
Operating System (cont’d)Operating System (cont’d)
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Manage computer programs Managing programs refers to how many
users, and how many programs, an operating system can support at one time
An OS can be single tasking, multi-tasking, cooperative multi-tasking, preemptive multi-tasking, multithreading and multiprocessing
Single tasking Runs only one program at a time
Operating System (cont’d)Operating System (cont’d)
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Multi-tasking Same concept as multiprogramming Allows 2 or more programs at the same time Divide the programs into active and inactive.
Active application is called foreground application and inactive application is background application
CPU does not run the programs simultaneously but manage the resources i.e. memory based on active/inactive applications
Operating System (cont’d)Operating System (cont’d)
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Cooperative Multi-tasking Based on multi-tasking concept, whereby
foreground application controls CPU until program ends
But if program crashes/hang, OS needs to be rebooted
Preemptive Multi-tasking Based on multi-tasking concept But if program crashes/hang, OS is able to
take over CPU so other programs can be maintained
Operating System (cont’d)Operating System (cont’d)
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Multithreading One program may execute more than one
task Example print and edit at the same time
Multiprocessing Use of 2 or more processor at the same time Programs run simultaneously Each processor manage own resources Hardware dependant esp. motherboard
Operating System (cont’d)Operating System (cont’d)
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Manage computer hardware Memory Unit
OS partitions the memory for each program. If memory is insufficient, OS may use virtual
memory, which allocates a portion of a storage medium to function as additional RAM
In virtual memory, programs/instructions are stored in fixed-sized unit called pages
If memory if full, OS will copy pages into swap file in hard disk and reloaded into memory when needed
Operating System (cont’d)Operating System (cont’d)
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Step 1. The operating system transfers the least recently used data and program instructions to disk because RAM is needed for other functions.
Step 2. The operating system transfers data and program instructions from hard disk to RAM when they are needed.
With virtual memory (VM), portion of hard disk is allocated to function as RAM
Operating System (cont’d)Operating System (cont’d)
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Input/Output Devices OS provides interrupt handler, a mini
program to handle interrupt from input/output devices.
Examples of interrupt are mouse click/scroll/keyboard punch
OS requires device driver to operates hardware devices. Drivers are loaded during booting
Operating System (cont’d)Operating System (cont’d)
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What is a device driver?
Device Device DriverDriver
Program that Program that tells operating system tells operating system how to communicate how to communicate
with devicewith device
With With Plug and PlayPlug and Play, , operating system operating system
automatically configures automatically configures new devices as you new devices as you
install theminstall them Also called Also called driverdriver
Operating System (cont’d)Operating System (cont’d)
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Spooling
Sending print jobs to buffer instead of directly to printer Print jobs line up in queue
Operating System (cont’d)Operating System (cont’d)
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Provides User Interface OS manages communication between the
computers and users Users may login, run application programs,
manage files (copy/save) and on/off computers using any type of interface
There are 3 types of command instructions:i. Command line
Instructions to be typed in i.e. to save a file into diskette is C:\WINDOWS>copy C:myfile.doc a:
Users have to memorize instructions
Operating System (cont’d)Operating System (cont’d)
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ii. Menu-driven User selects instruction from a text-based pull-
down menu Instructions are entered either via mouse click/
keyboard <ENTER> of arrow keys
iii. Graphical user interface (GUI) User selects instruction by mouse click or
keyboard <ENTER> icons
Operating System (cont’d)Operating System (cont’d)
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User interface
command-line interface menu-driven interface
Controls how you enter data and instructions and how information displays on screen
Operating System (cont’d)Operating System (cont’d)
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Graphical User Interface (GUI)
User interacts with menus and visual images such as icons and buttons
Operating System (cont’d)Operating System (cont’d)
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Device-dependent
Runs only on specific type of
computer
Some characteristics of operating systems
Downward compatible
Works with application software written for earlier
version of operating system
Upward compatible
Runs on new versions of operating system
Proprietary software
Privately owned and limited to specific vendor
or computer model
Device-independent
Runs on many manufacturers’
computers
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Stand-aloneStand-alone
Three categories of operating systems
EmbeddedEmbedded NetworkNetwork
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Stand-alone operating systems
Example: Windows
Windows Version Year Released
Windows 3.x 1990
Windows NT 3.1 1993
Windows 95 1995
Windows NT Workstation 4.0 1996
Windows 98 1998
Windows Millennium Edition 2000
Windows 2000 Professional 2000
Windows XP 2001
Windows XP SP2 2004
Windows Vista 2006
Operating System (cont’d)Operating System (cont’d)
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Fast, reliable Windows operating system
Stand-Alone Operating SystemsStand-Alone Operating Systems Windows XP
Available in five editions: Home Edition, Professional Edition, Tablet PC Edition,Media Center Edition,and 64-bit Edition
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Successor to Windows XP, containing a new interface and new / enhanced features
Stand-Alone Operating SystemsStand-Alone Operating Systems Windows Vista
Available in several editions, grouped into Home and Business categories
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Stand-Alone Operating SystemsStand-Alone Operating Systems
Mac OS X
Available only for computers manufactured by Apple
Macintosh operating system has been model for most GUIs
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Stand-Alone Operating SystemsStand-Alone Operating Systems
UNIX Used by power users
because of its flexibility and power
Most versions offer GUI
Available forcomputers of allsizes
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Stand-Alone Operating SystemsStand-Alone Operating Systems Linux
Red Hat provides a version of Linux called Red Hat Enterprise Linux.
Popular, free, multitasking UNIX-type operating system
Open-source software—code is available to public
Both a stand-alone and a network operating system
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Network operating system
Allows users to share printer, Internet access, files, and programs on a network
Administers security by establishing user name and password for each user
Operating System (cont’d)Operating System (cont’d)
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Network Operating SystemsNetwork Operating Systems
Examples of network
operating systems
NetWareNetWare
Designed for Designed for client/server client/server
networksnetworks
Windows Windows Server 2003Server 2003
Upgrade to Windows Upgrade to Windows 2000 Server2000 Server
UNIX / LinuxUNIX / Linux
Multi-purposeMulti-purposeoperating systemoperating system
SolarisSolaris Version of UNIX Version of UNIX developed by Sun developed by Sun
MicrosystemsMicrosystems
Specifically for Specifically for e-commerce e-commerce applicationsapplications
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Embedded Operating SystemsEmbedded Operating Systems
Embedded operating system
Found on most mobile computers, PDAs, and other small devices
Windows CE is scaled-down version of Windows
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Embedded Operating SystemsEmbedded Operating Systems Operating systems for PDAs
Windows Mobile for Pocket PC Palm OS for Palm
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Embedded Operating SystemsEmbedded Operating Systems
Embedded Linux
Scaled-down Linux operating systemdesigned for PDAs, smart phones,smart watches, set-top boxes,Internet telephones, and otherdevices
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Embedded Operating SystemsEmbedded Operating Systems
Symbian OS
Open-source, multitasking operating system designed for smart phones
Make telephone calls, save appointments, browse Web, send and receive e-mail and faxes, and more
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3.2 Utility Program
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A small program that provides an addition to the capabilities provided by the operating system
Performs maintenance-type tasks, usually related to managing a computer, its devices, or its programs.
Utility programUtility program
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File manager
Performs functions such as copying, renaming, deleting, and moving files
Image viewer displays contents of graphics file when you double click on it
OS Utility ProgramOS Utility Program
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Personal firewall
Detects and protects a personal computer from unauthorized intrusions
The latest update to Windows XP automatically enables the built-in personal firewall upon installation
OS Utility ProgramOS Utility Program
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Uninstaller
In Windows XP, In Windows XP, uninstaller is in Add/Remove uninstaller is in Add/Remove
Programs in Control PanelPrograms in Control Panel
Removes a Removes a program and program and
all associated filesall associated files
OS Utility ProgramOS Utility Program
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Disk scanner
Detects and corrects problems on hard disk
Searches for and removes unnecessary files
OS Utility ProgramOS Utility Program
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Disk defragmenter
Reorganizes files and unused space on hard disk so programs run faster
fragmented disk
disk after defragmentation process
OS Utility ProgramOS Utility Program
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Diagnostic utility
Compiles technical information about hardware and some software
Prepares report outlining problems
OS Utility ProgramOS Utility Program
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Backup utility
Copies selected files or entire hard disk onto another storage medium
Most compress files during backup to require less storage space
OS Utility ProgramOS Utility Program
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Screen saver
Causes monitor’s screen to display moving image or blank screen if there is no activity for a specified time
To secure computer, user configures screen saver to require password to deactivate
OS Utility ProgramOS Utility Program
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Stand-Alone Utility ProgramsStand-Alone Utility Programs Antivirus program
Identifies and removes viruses in memory, storage media, and incoming files
Must be updated frequently
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Stand-Alone Utility ProgramsStand-Alone Utility Programs What is a virus?
Potentially damaging computer program Affects computer without user’s knowledge
SIGNS OF SIGNS OF VIRUS VIRUS
INFECTIONINFECTION
• An unusual message or image is displayed on the computer screen• An unusual sound or music plays randomly• The available memory is less than what should be available• A program or file suddenly is missing• An unknown program or file mysteriously appears• The size of a file changes without explanation• A file becomes corrupted• A program or file does not work properly• System properties change
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Stand-Alone Utility ProgramsStand-Alone Utility Programs Spyware
Program placed on a computer without the user’s knowledge that secretly collects information about the user
Often enters a computer as a result of a user installing a new program A spyware remover is a program that detects and deletes spyware
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Programs that remove or block certain items from being displayed
Pop-up Blockers
Stand-Alone Utility ProgramsStand-Alone Utility Programs Internet filters
Anti-SpamPrograms
WebFilters
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Stand-Alone Utility ProgramsStand-Alone Utility Programs File compression utility
Shrinks size of files to free up room and improve performance
Compressed files are sometimes called zipped files
Two popular utilities: Winrar and WinZip
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Stand-Alone Utility ProgramsStand-Alone Utility Programs CD/DVD burning software
Writes text, graphics, audio, and video files to a recordable or rewriteable CD or DVD
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Stand-Alone Utility ProgramsStand-Alone Utility Programs Personal computer maintenance utility
Identifies and fixes operating system problems and disk problems
Some continuously monitor computer to identify problems before they occur