SC161-Lecture3

Thiti Theerathean
Center for Teaching Excellence
University of the Thai Chamber of Commerce
E-mail : thiti_the@utcc.ac.th

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T h e P r i n c i p l e s o f I n f o r m a t i o n Te c h n o l o g y .
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The System Software consists of the programs that control or maintain the
operations of the computer and its devices. It serves as the interface between
user, the application software and the computer’s device.
There are two types of system software :
 Operating system.
 Utilities programs.

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Operating system
An operating system (OS) is a set of programs containing instructions that work
together to coordinate all the activities among computer hardware resources
Start the computer Provide a user interface Manage programs
Manage memory
Schedule jobs and
Configure devices
Establish an internet
connectionMonitoring
Performance
File management
Control a network
Administer security

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The process of starting or restarting a computer is called boot
Cold boot
• Turning on
a computer
that has
been
powered off
completely
Warm boot
• Using the
operating
system to
restart a
computer

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Power ON

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A User Interface controls How you enter data and instructions and How
information is displayed on the screen.
Two types of user interfaces are
With a graphical user interface (GUI),
you interact with menus and visual
images
With a command-line interface, a user
uses the keyboard to enter data and
instructions

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Single user
and
Multiuser
Single tasking
and
multitasking
Foreground
and
background
How an operating system handles programs directly affects your
productivity
A computer with separate processors also can serve as a
Fault-tolerant computer.

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The memory management is to optimizes the use of RAM.
 allocates or assigns data and instructions to area of memory.
 while they are being processed.
 monitor contents of memory.
 clears items from memory when processor no longer
requires them.

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What is Virtual memory ?
The Virtual memory (VM) is a concept in which the OS allocates a
portion of a storage medium.
 Uses an area of the hard disk for virtual memory, called
swap file.
 Swaps data and information between memory and storage.
 Swapping Technique is called Paging

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A job is ….  Receiving data from input device.
 Sending information to output device.
 Processing instructions.
 Transferring items between storage and
memory.
The Operation System determines the order in which
jobs are processed.

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Sometimes, a device already may be busy processing one job when
it receives a second job. While waiting for devices to become idle,
the OS places items in Buffer.

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A driver is a small program that tells the
operating system how to communicate
with a specific device
Plug and Play automatically configures
new devices as you install them
Today, many devices and operating system
support Plug and Play.
If you attach a new device to a computer. Its driver must be installed
before you can use the device.

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The OS provide a Connect to a
network wizard that guides users
through the process of setting up
a connection between a computer
and ISP .

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A Performance monitor is a program that assesses and reports
information about various computer resources and devices.

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 Searching for files
 Viewing images
 Sorting
 Formatting
 Copying
 Renaming
 Deleting
 Moving files

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 Some operating systems are designed to work with a server
on a network
 A server operating system organizes and coordinates how
multiple users access and share resources on a network
 Server is computer that controls
access to network and provides
centralized storage area.
 Other computers on network are
called Clients.

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Each user has a user account
 A user name, or user ID, identifies a
specific user
 A password is a private combination
of characters associated with the
user name
The network administrator use network OS to establish permissions to
resource. These permissions define who can access certain resources and
when they can access those resources.

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Types of Operating Systems
A stand-alone operating system is a
complete operating system that works
on a desktop computer, notebook or
mobile computing device
A network operating system typically
resides on the server and is designed
specifically to support all sizes of
networks
An embedded operating system resides
on a ROM chip on a mobile device or
consumer electronic device

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A Utility program, also called a Utility, is a type of system
software that allows a user to perform maintenance-type tasks.
 File manager
 Search Utility
 Image Viewer
 Uninstaller
 Disk Cleanup
 Disk Defragmenter
 Backup / Restore Utility
 Personal Firewall
Windows Utility
 Antivirus
 Spyware Remover
 Internet Filters
 File Compression
 Disc Burning
 System Tweak
Utility Programs

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A file manager is a utility that performs functions
related to file management
 Displaying a list of files
 Organizing files in folders
 Copying, renaming, deleting, moving, and
sorting files and folders
 Creating shortcuts
A search utility is a program that attempts
to locate a file on your computer based on
criteria you specify

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An image viewer allows users to display, copy,
and print the contents of a graphics file
An uninstaller removes a program, as well as
any associated entries in the system files

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A disk cleanup utility searches for and removes
unnecessary files
 Downloaded program files
 Temporary Internet files
 Deleted files
 Unused program files
A disk defragmenter reorganizes the files
and unused space on a computer’s hard disk
so that the operating system accesses data
more quickly and programs run faster

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 A backup utility allows users to copy files
to another storage medium
 A restore utility reverses the process and
returns backed up files to their original form
A personal firewall detects and protects
a personal computer from unauthorized
intrusions

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 Antivirus
 Spyware Remover
A virus describes a potentially damaging computer
program that affects a computer negatively
A worm copies
itself
repeatedly in
memory or
over a network
A Trojan horse
hides within or
looks like a
legitimate
program
An antivirus
program
protects a
computer
against viruses

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 Antivirus
 Spyware Remover

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 Antivirus
 Spyware Remover
 An unusual message or image is displayed on the 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 dose not work properly.
 System properties change.
 The operating system runs much slower than usual.

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 Antivirus
 Spyware Remover
Spyware is a program placed on
a computer without the user’s
knowledge that secretly collects
information about the user
• A spyware remover detects
and deletes spyware and other
similar programs
Adware displays an online
advertisement in a banner or
pop-up window
• An adware remover is a
program that detects and
deletes adware

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 Antivirus
 Spyware Remover
 Filters are programs that remove or block certain items from
being displayed
Web filters
Anti-spam
programs
Phishing
filters
Pop-up
blockers

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A file compression utility shrinks the size of a file(s)
 Compressing files frees up room on the storage media
 Two types of compression :
Lossy
Lossless
When Lossy data compression is applied to a file,
the quality of the file will decrease slightly each
time you compress the file.
You will be unable to restore the file to its exact
original state.
Lossless data compression is used when you must
compress a file, but also must be able to return
that file to its exact original state

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Disc burning software writes text, graphics,
audio, and video files on a recordable or
rewritable optical disc
A computer maintenance utility
identifies and fixes operating system
problems, detects and repairs disk
problems, and includes the capability of
improving a computer’s performance

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An Application Software consists of programs designed to make users more
productive and assist them with personal tasks. It has a variety of uses :
 To make business activities more efficient.
 To assist with graphics and multimedia projects.
 To support home, personal, and educational tasks.
To facilitate communications.

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 Packaged software, mass-produced
 Custom software, performs functions specific to a business or
industry
 Web-based software, hosted by a Web site
 Open source software, provided for use, modification, and
redistribution
 Shareware, copyrighted software that is distributed free for trial
period
 Freeware, copyrighted software provided at no cost
 Public-domain software, freeware with no copyright restrictions
Available in a variety of forms:

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Business Software
A Business Software is application software that assists people in becoming
more effective and efficient while performing their daily business activities.

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Multimedia Software
Power users often use sophisticated software that allows them
to work with graphics and multimedia.

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Home and Personal Software
The application software is designed specifically for home, personal and
education use. Most of programs in this category are relatively inexpensive.
 Software Suite for personal use
 Personal Finance software
 Image Editing software
 Clip art / Image Gallery
 Video and Audio Editing software
 Travel and Mapping software
 Educational and Reference software

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Communication Software
Web Browser E-Mail Instant Messaging Chat Room
Text, Picture, Video
Messaging
RSS Aggregator Blogging
Newsgroup/Message
Board
FTP Video Conferencing

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Web Applications
A Web application is a Web site that
allows users to access and interact
with software from any computer or
device that is connected to the
Internet

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Learning Tools for Application Software
 Web-based training is a type of CBT
that uses Internet technology and
consists of application software on
the Web
 Distance learning (DL) is the delivery
of education at one location while
the learning takes place at other
locations

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



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A computer program is a series of instructions that
directs a computer to perform tasks.
 The source of a program may be
used to describe an algorithm to
a human reader.
 These modules are stored as a collection
of files.
 It is often written by computer
programmers.
 Source code is written in a
programming language.

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 Executable file (.exe / .com) is a part of a program that
actually sends commands to the processor.
 Dynamic Link Library File (.dll) is a partial .exe file. It will
not run on its own, its commands are accessed by another
running program.
 Initialization File (.ini) contains information that programs
can use as they run.
 Help file (.hlp / .chm) contains an indexed and cross-linked
format of help information.
The common extensions for program files

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Source code or Source program
 Code refers to statements that are written in any programming language.
 Programming language enable the programmer to describe a program
using a variation of basic English. The results are saved in a file and called
Source Code.
 Source codes are compiled or interpreted to Machine language or
Machine code.
Source Code Translator
1 1 0 1 0 0 1
1 0 1 0 0 0 1 1 0 1 0
0 1 0 0 0 1 1 1 0 1 0 1 1
0 0 0 1 1 0 1 1 1 1 0 1 1 1 0
1 0 0 1 0 0 1 0 0 1 0 1 0 0
1 1 1 0 0 1 1 1 0 0 0 1 1 0
0 1 1 0 1 1 0 1 1 0 0 1 1
0 1 1 0 1 0 0 1 1 1 0
0 0 1 1 0 1
Machine Code

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Programming Languages : Low-Level Languages

– The first generation of programming languages.
– The only language the computer directly recognize.
– Instructions use a series of binary digits.
– Coding is tedious and time-consuming.

– The second generation of programming languages.
– Use Symbolic instruction code.
– Source code is converted to machine code by Assembler.
– Used to control hardware.

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Programming Languages : Procedural Languages
 The third-generation language (3G) that uses a series of English-like words and
arithmetic symbols to write instruction.
 The programmer writes instructions that tell the computer what to accomplish
and how to do.
 Short for COmmon Business-Oriented Language
 designed for business application.
 Useful for processing transactions on mainframe.
 COBOL
 C language  Originally designed for writing system software.
 Used most often with the UNIX.
 BASIC  short for Beginner's All-purpose Symbolic Instruction Code
 easy-to-understand and used to help for teaching the
fundamentals of programming

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Compiler  A Compiler converts the entire source program
into machine language.
 The output of the compiler is called object code.
 You can copy the object code onto any similar
platform and run the program.
 An Interpreter translates and executes each statement
of source code at the time.
 Programmer can correct any errors before it translates
the next line of code.
 It runs slower than compiled code.
Interpreter
Before executing the program, you must use either a compiler or an
interpreter to convert the source program into machine language.

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Programming Languages : OOP Languages
 An Object-Oriented Programming (OOP) language allows programmers
the ability to reuse and modify existing objects.
 An Object is an item that can contain both data and the procedures that
read or manipulate that data.
 Each data element is called an Attribute or Property.
 The procedure in the object is called an Operation or Method.
Other advantages include:
Objects can be
reused
Programmers create
applications faster
Work well in a RAD
environment
Most program
development tools
are IDEs

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 Java  Developed by Sun Microsystems.
 Object code is called Bytecode which is machine independence.
 Uses a Just-In-Time (JIT) compiler to convert bytecode into
machine dependence code.
 C++  An extension of the C programming language.
 Additional features for working with objects, classes, events
and other object-oriented concepts.
 C#  based on C++ and was developed by Microsoft.
 Like JAVA , it uses a JIT compiler but it resulting code is called
Microsoft Intermediate Language (MSIL)

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Programming Languages : Markup Languages
Tags
 Designed for the definition and
presentation of text.
 Used to specify the formatting
are called tags.

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 HTML  Short for Hyper Text Markup Language.
 Uses to format documents for display on the Web.
 User for display data.
 xHTML  Short for eXtensible HTML.
 Includes features of HTML and XML.
 Short for eXtensible Markup Language.
 Allows to create customized tags and use predefined tags to
display content appropriately on various devices
 Used for sharing data.
 XML
 WML  Short for Wireless Markup Language.
 subset of XML and is used to design pages for micro-browsers.

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Programming Languages : Script Languages
 An interpreted language is used to develop a small program
that run inside of another program.
 "Scripts" are distinct from the core code of the application that
written in a different language.
 Designed for gluing software components together.
 Referred to as glue languages or system integration languages.
 Popular script languages include PHP , JavaScript , VBScript

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Programming Development
The Program development consists of a series of steps programmers use to build
computer programs

Step 1 – Analyze Requirements
• To initiate program development, programmer:
– Reviews the requirements
– Meets with the systems analyst and users
– Identifies input, processing, and output
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Step 2 – Design Solution (con.)
• In structured design, the programmer typically begins with a
general design and moves toward a more detailed design
• Programmers use a hierarchy chart to show program modules.
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• A program flowchart graphically
shows the logic in a solution
algorithm 58

• The sequence control structure
shows one or more actions
following each other in order
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• The selection control structure tells the program which action
to take, based on a certain condition
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• The repetition control structure enables a program to perform one
or more actions repeatedly as long as a certain condition is met
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• Flowcharting software makes it easy to modify and
update flowcharts
– SmartDraw
– Visio
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• Pseudocode uses a
condensed form of
English to convey
program logic
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Step 3 – Validate Design
• Check for logic errors using test data
Develop
various
sets of test
data
Determine
the
expected
result
Step
through
the
algorithm
Compare
the results
Repeat
steps for
each set of
test data
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Step 4 – Implement Design
• Implementation of the design includes using a program
development tool that assists the programmer by:
• Generating or providing some or all code
• Writing the code that translates the design into a computer program
• Creating the user interface
• Extreme programming is a strategy where programmers
immediately begin coding and testing solutions as soon
as requirements are defined
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Step 4 – Implement Design
• Program development tools
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Step 5 – Test Solution
The goal of program testing is to ensure the
program runs correctly and is error free
• Errors include syntax errors and logic errors
• Debugging the program involves removing the bugs
• A beta is a program that has most or all of its features and
functionality implemented
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Step 6 – Document Solution
• In documenting the solution, the programmer
performs two activities:
Review the
program code
Review all the
documentation
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