Vedanta Let's Log in Computer Science Book - 9.indd

Vedanta Let’s Log in Computer Science | Book 9

when the person in not using a computer. For example, printers or plotters
are hard-copy output.

Monitor

The keyboard is the most commonly used input device and the monitor is the most
commonly used divice for producing soft-copy output device on most personal
computer systems. As you use your computer to type a letter, copy files, or surf
the Internet, hardly a moment goes by when you are not looking at your monitor.
When people work in graphics, they want to see whether the images are crisp
and clear and how well graphics are displayed. Two important hardware devices
determine the quality of the images you see on any monitor: the monitor itself and
the video controller.
The basic types of monitors used today are LCD (Liquid Crystal Display), LED
(Light Emitting Diode) and OLED (Organic Light Emitting Diode). LCD flat-panel
monitors are thinner and lighter. They are used commonly with portable computer
systems like notebook computers, where LED monitors one a very short depth and
light. They occupy less space, consume low power, and provide higher contrast and
better viewing angles than LED.

LCD LED OLED

Monitors

OLED (Organic Light Emitting Diode) is a new display technology that is brighter,
more efficient and thinner. It has better refresh rates and contrast than an LCD.
OLEDs deliver the best picture quality ever and are used in high-end smartphones
and tablets.

Printer

Besides the monitor, the other important output device is the printer. Generally,
printers fall into two categories: impact and nonimpact. An impact printer

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creates an image by using pins or hammers to press an indeed ribbon against the
paper. The most common type of impact printer is the dot matrix printer. Other
types of impact printers are line printers and band printers.
Nonimpact printers use other means to create an image. Inkjet printers, for
example, use tiny nozzles to spray droplets of ink onto the page. Laser printers
work like photocopiers.

Printers

In the early years of computing, dot matrix printers were the most commonly used
printing devices. They are not as prevalent now, although dot matrix printers
are still popular in business and academic settings because they are relatively
fast and cost effective in operation. They do a good job of printing text and simple
graphics. Inkjet printers now offer much higher quality for about the same price,
and they have become more popular than dot matrix printers at home and small
businesses. Laser printers are also popular at home and businesses, but they are
more expensive to buy and operate than either inkjet to dot matrix devices.

Three Dimensional Printer (3D) 3D printer

Impact printer and non-impact printer print text on
paper but 3D printer prints an object. For example, any
playing toys or any machinery parts are printed through
the 3D printer. 3D printing builds parts out of plastic,
metal and other materials directly from CAD (Computer-
Aided Design) drawings that have been cross-sectioned
into thousands of layers. This technology helps to build a
3D object by modelling. This technology is called additive
manufacturing.

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Graph Plotter

A plotter is a special kind of output device. It is like a printer because it
produces images on paper, but the plotter is typically used to print large-format
images, such as construction drawings created by architects. Generally, plotters
are more expensive than printers. The different types of plotters are:

(i) Flatbed Plotter (ii) Roller Plotter (Drum Plotter)
(iii) Electro-Static Plotter (iv) Inkjet plotter

Flatbed Plotter Roller Plotter (Drum Plotter) Electro-Static Plotter Inkjet plotter

Plotters

Speaker

Computer speakers, or multimedia speakers are external speakers, commonly
equipped with a low-power internal amplifier.
Some of the slightly better computer speakers
have equalization features such as bass and treble
controls, improving their sound quality to some
extent. Sound systems are especially useful to
people who use their computer to create or use
multimedia products, watch videos, or listen to
music, or participate in online activities such as
videoconferences or distance learning. Computer
speakers range widely in quality and in price. Speakers

Projector

Projector is an output device that can take the
display of a computer screen and project a large
version of it onto a flat surface. Projectors are
often used in meetings, seminars, conferences
and presentations so that everyone in the

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room can view the presentation in the magnified screen. Projectors are classified
into three types. They are:

i) Cathode Ray Tube Projector (CRT)

In the early days of projectors, CRT
projectors were commonly used. They utilize
three tubes: one for each of the primary colors
red, green, and blue. Due to their large size, low
light output and the frequent need to converge
and align the images projected from each of the
three tubes, they are no longer in use nowadays.

ii) Liquid Crystal Display projector (LCD) CRT Projector

LCD projectors work by utilizing polarized mirrors that pass and reflect only
certain colors of light. This causes each channel
of red, green and blue to be separated, and later
re-converged via a prism after passing through
an LCD panel that controls the intensity and
saturation of each color. LCD projector can
achieve greater brightness at lower energy
consumption. It is comparatively smaller than
CRT projectors.
LCD Projector

iii) Digital Light Processing projector (DLP)

DLP projectors can be classified as one- DLP Projector
chip or three- chip. One-chip DLP projectors
can produce more than 16 million colors while
three-chip models can produce more than 35
trillion colors. This allows DLP projectors to
reproduce more natural and real like images on
the screen.

Ports

All modern computers come with the same basic set of ports. These allow you to
connect common devices to your computer. Without these ports, your computer
would not boot properly and if it did, you would be unable to interact with the
software on the system. Most plugs fit where they belong to. The most commonly
used ports are:

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Mouse and Keyboard Ports
They accept the keyboard and mouse plugs.
Two Universal Serial Bus (USB) Ports
They accept any number of devices including cameras and
joysticks.
Monitor Port
Most monitors connect to the three-row port on the right side of
the image. This can be found either by the serial port or with the
expansion cards.
Parallel Port
Most common uses are to connect older printers to the computer.
Serial Port
Serial Port is connected to external modems.

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Network Port
This port allows your computer to plug into a network or use a
high-speed Internet connection.
Audio Port
There are typically three audio ports on modern computers. The
green speaker port is for our headphones or desktop speakers.
The pink microphone port is for a small microphone. The yellow
speaker out is designed for serious audiophiles to connect their
computer to a home stereo system.
Modem Port
It connects your computer to a phone line. The most common use
for a modem is internet access.

POINTS TO REMEMBER

The physical parts of computer which can see, feel, and touch are called computer
hardware.

The complete cycle of four units as fetch, decode, execute, and write back of
microprocessor for processing the instruction is called instruction cycle.

Motherboard helps data communication between different hardwares.

Microprocessor gets data and instruction from various hardware and processes it
with the help of software to produce information as an output to user.

The physical part of computer that stores data, information, and software temporarily
or permanently is called memory or storage.

Secondary memory is used to store data and instruction permanently for future use.

Hard disk stores large amount of data and information permanently. It is made up of
aluminium materials while its surface is coated with ferromagnetic element.

Hard disk can be replaced and upgraded with SSD (Solid State Drive) as a new
technology.

A storage unit consists of primary and secondary storages.

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The most commonly used optical storage discs are CD, DVD, Blu-ray disc, etc.
The devices which enter raw data and instructions into the computer system are
called input devices.
The device which displays meaningful information from the computer is called an
output device.
Additive manufacturing technology is used by computer-aided-design (CAD)
software or 3D object scanners or printers.

Exercise

1. Answer the following questions:
a. Define computer hardware.
b. What is the motherboard?
c. Why is it necessary to have a backing storage device in computer?
d. What is printer? Explain different types of printers.
e. Briefly describe the main functions of CPU.
f. Define computer memory? Distinguish between primary memory and secondary
memory.
g. What are the two most common input and output devices?
h. Why is RAM called temporary memory?
i. Why is ROM called a non-volatile memory?
j. What is secondary storage?
k. What is the advantage of random access device over sequential access device?
l. Differentiate between the hard disk and solid state drive.
m. Explain why a computer must have a primary and secondary memory.
n. Write the difference between impact and non-impact printer.
o. Why do we use a bar code reader?

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p. Classify the following printers into impact and non-impact:
Thermal Printer, Laser Printer, Daisy Wheel Printer, Dot matrix Printer.

q. What is graphic plotter?
r. What is mouse? How many click buttons does it have?
s. What is Joystick? What is the use of Joystick?
t. Differentiate between microphone and speaker.
u. What is the projector? What are its types?
v. Classify the following devices into Input, Output, and Storage devices.

Tape, Hard disk, Touch Pad, Microphone, Monitor, Scanner, Speaker, DVD, Joystick,
Blue-ray Disc, Printer, OLED

2. Give appropriate technical terms of the following:
a. A device to convert normal picture into a digital picture.
b. A device to give hard output.
c. A program written in ROM
d. Printer which prints by striking the ribbon with pins.
e. Printer which sprays ink to the paper while printing.
f. A device connected to a computer for remote access.
g. A spare copy created of important program and documents.
h. Physical components of the computer.
i. The high speed memory kept between CPU and main memory.
j. A storage media that stores data and programs optically.
k. An optical disc which enables pre-recorded data to be read.
l. The device which gives hard copy output.
m. The device which enters text, graphics, and pictures directly into the computer.
n. It is a connector, generally found on the back of the computer that allows a user to
connect different devices to the computer.
o. A main circuit board where processor and other vital components are mounted.
p. A volatile memory in a computer.
q. Printer with the similar working mechanism of a photocopier.

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3. Give full forms of the following abbreviations:

a. PCB b. BIOS c. ROM d. RAM e. RPM
i. FM j. USB
f. TPI g. CD h. DVD n. CRT o. LCD

k. CAD l. OMR m. OCR

4. Fill in the blanks.

a. A computer to produce useful output its ……………..and ………..must work together.
b. …………….cannot be utilized without supporting hardware.
c. The first microprocessor was the …………..
d. …………., ………. and ……….microprocessors are now common.
e. …………….is the heart of any normal computer.
f. The motherboard as the ……………..board in a computer.
g. The device that acts as supplement to main memory is called …………………
h. A standard compact disc can store …………..of data or about ………..minutes of

audio.
i. Compare to hard disk drives CD-ROM drives are………….

5. Choose the best answer:

a. Physical components of a computer are ..................

i. software ii. hardware iii. both a and b iv. None of them
iv. CIOS
b. Motherboard does not contain .................. iv. Intel 2004
iv. All of them
i. PCB ii. BIOS iii. Memory iv. EEPROM
iv. None of them
c. .................. is the first microprocessor.

i. Intel 2002 ii. Intel 4002 iii. Intel 4004

d. .................. is a volatile memory.

i. ROM ii. RAM iii. Flash memory

e. .................. is not the form of ROM.

i. TROM ii. PROM iii. EPROM

f. .................. is magnetic storage device.

i. DVD ii. Blu ray iii. Floppy disk

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g. Small pressure and motion sensitive area on a portable computer that you can use to
move the mouse pointer

i. Track ball ii. Joystick iii. Scanner iv. Touch pad

i. .................. monitors actually display two colors.

i. Monochrome ii. Gray scale iii. CRT iv. LCD

j. Hard disk can be replaced and upgraded by ………...

i. pendrive ii. magnetic disk iii. SSD iv. magnetic tape

7. Write short note: b) 3D printer c) QR Code
a) Motherboard e) OLED monitor
d) SSD

Activities

1. Prepare a power point presentation about different computer hardwares found in
present time and present in your class as a group discussion.

2. Draw in chart paper about different types of computer hardware with name and
paste in your classroom.

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Unit

1.5

Introduction

The ingredient that enables a computer to perform a specific task is software, which
consists of instructions. A set of instructions that drive a computer to perform
specific tasks is called a program. A program or group of programs are designed
for end users. These instructions tell the machines’ physical components what to do:
without the instructions, a computer cannot do anything at all. When a computer
uses a particular program, it is said to be running or executing that program.

Different types of computer software

Although the array of available programs is vast and varied, most softwares fall
into two major categories: System software and application software. Systems
software consists of low-level programs that interact with the computer at a very
basic level. This includes operating systems, compilers, and utilities for managing
computer resources.
In contrast, application software (also called end-user programs) includes
database programs, word processors, and spreadsheets. Figuratively speaking,
application software sits on top of systems software because it is unable to run
without the operating system and system utilities.

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System Software

The system software is any program that controls the computer’s hardware or that
can be used to maintain the computer in some way so that it runs more efficiently.
It includes operating systems, assemblers, compilers, file management tools, device
drivers, utilities, and more. Since system software runs at the most basic level of
computer, it is called “low-level” software. It generates the user interface and
allows the operating system to interact with the hardware. Fortunately, we do not
have to worry about what the system software is doing since it just runs in the
background.

1) Operating System (OS) User
Application
An operating system tells the computer
how to use its own components. Examples of
operating systems include Microsoft Windows,
the Macintosh Operating system, Linux,
Windows 7/ 8/ 10, UNIX, Android KitKat, Android
Marshmallow, Apple’s iOS, etc.

An operating system is essential for any computer, Operating system
because it acts as an interpreter between the
hardware, application programs, and the user.

When a program wants the hardware to do
something, it communicates through the operating
system. Similarly, when you want the hardware to
do something (such as copying or printing a file),
your request is handled by the OS. In a network Hardware

environment, a network operating system allows
computers to communicate and share data across a network while controlling
network operations and overseeing the network’s security.

Some basic functions of operating system software are:
It provides easy interaction between user and computer.
It starts the computer and controls its entire functioning.
It controls and manages input / output devices.
It manages various types of memories such as primary, secondary, cache, etc.
It interprets and executes the commands of application programs.
It provides platform to run other software programs.

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It provides security to users’ jobs and files.
It allows users to share data and software among themselves.
It notifies the user about any fault that may occur in the computer.
According to the user operating system is divided into two types. They are:
i. Single-User Operating System
ii. Multi-User Operating System

i. Single User Operating System

As the name implies, Single-user operating system is designed to manage the
computer so that one user can effectively do one thing at a time. The Palm OS for
Palm handheld computers is a good example of a modern single-user, single-task
operating system. This is the most common type of OS used on a home computer,
as well as on computers in offices and other work environments. There are two
general types of the single-user operating system: single task and multitasking
systems. MS-DOS, Windows 3X, Windows 95/97/98 are the examples of single user
operating system.

ii. Multi-User Operating System

A multi-user operating system allows multiple users to use the same computer
at the same time and / or different times. In other words, a multi-user operating
system is a computer operating system that allows multiple users on different
computers or terminals to access a single system with one OS on it. These programs
are often quite complicated and must be able to properly manage the necessary
tasks required by the different users connected to it. Unix, Virtual Memory System
(VMS), and mainframe OS are the examples of multi-user operating system.

CUI (Character User Interface)

In this type of operating system software, user gives command or character to
perform the tasks. Keyboard is used to give command in this operating system. It
is not user friendly as compared to GUI operating system software. DOS, UNIX,
Novel Netware, etc. are the example of character user interface.

GUI (Graphical User Interface)

In this type of operating system software, user gives command to perform the tasks
by clicking on icons, buttons, and menus using mouse. It uses keyboard as well as

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mouse and it is user friendly as compared to CUI operating system. MS Windows
7/8/10, Linux, etc. are the example of GUI.
Nowadays, Microsoft Corporation develops GUI based operating system software
and use. Windows operating system software users are growing in number in
the world. Windows is a GUI based operating system software that controls all
activities of computer system. In this operating system software, the user use
different application program and document display on window, so it named as
window.
Mouse is used to open file. Computer shuts down and perform different command
in windows operating system software, so that user no needs to remember long
command to perform task. Nowadays, windows10 is the latest operating system
software.

The Desktop Desktop

When we switch on our computer,
after the welcome message of the
windows, the first screen that we
see is desktop. It contains icons,
program or files shortcuts, start
button, and taskbar needed for
accessing the available programs.

Wallpaper

The background picture of Windows desktop
is called the desktop background. It is also
called the wallpaper. Desktop wallpaper is the
image that fills the background of our computer
screen when all programs are closed.

Change the Wallpaper

Right-click on your desktop and choose
Personalize.
Select Picture from the Background drop-
down list.
Close the Settings window.

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Icons

The small labelled pictures present on the
desktop are called icons. These icons are used
to open specific programs, folders, or documents.
Desktop icons are also called shortcuts. Some
commonly found icons are This PC, Recycle
Bin, etc.

This PC Icon

This PC icon represents all the hard-disk drives, saved files, and
folders. Using it, we can access all the drives, folders, and files stored
in a computer. Double-click on the icons to open it. You can open
drives, folders, and files in it by double-clicking on their icons.

Recycle Bin Icon

The Recycle Bin icon represents all the deleted folders and
files. It acts as a dustbin for our computer. It is used to store our
deleted items. We can restore our deleted files from the Recycle
Bin. However, once a file is deleted from the Recycle Bin, it cannot
be recovered.

Taskbar

Taskbar is the long horizontal bar present at the bottom of the desktop. The
different parts of a taskbar are shown below:

Taskbar

Working with files and folders

File

A file is a collection of related information. The icon of the file tells us what type
of file it is. All the data in your computer is stored in file. There are many different
types of files in computer. Image files, program files, text files, music files, etc are
some of its type.

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A filename consists of two parts: filename and extension.

Filename can be any name given by the user while the extension is given by the
program where it is created.

Annapurna.jpg extension

filename

Folder

A folder is a container for storing files and other folders. A collection
of related files can be grouped in a common folder. A folder within a
folder is called a sub-folder.

Creating Folder

To create a new folder on the desktop, follow the given steps.
Right click on the blank area of the desktop.
A pop-up menu appears.

Select New and Click on Folder
Type in the folder name.
Press on Enter.
A new folder is created.

Selecting file and folder

To select a single file or folder, click on it.
To select multiple files and folders, click one by one on every file or folder with
Shift key pressed.

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To select multiple files and folders that are not placed together, select the file
or folder with Ctrl key pressed.

Opening a file/folder

To open a file or folder, double-click on it. The file/folder opens and you can
view its contents.

Renaming a file or folder

Right click on the icon of the chosen
file or folder.
A pop-menu appears. Click on
Rename.
Type in the new name.
Press on Enter.

Deleting a File or a Folder

Right-click on the file or folder that you want to delete.
A pop-up menu appears. Click on Delete option.
or
Select the file or folder.
Press on Delete key.

When we delete a folder or file, by default,
windows moves it to the Recycle Bin.
The file/folder remains in the Recycle Bin
unless it is deleted from there also.

Restoring deleted files or folders from Recycle Bin

Restore means bringing back the deleted files or
folders to its original location from Recycle Bin.
Double-click on the Recycle Bin icon present on
the desktop.
Right-click on the file or folder you want to
restore.
Click on restore.

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Moving a File or Folder

Cutting and pasting are typical Windows functions. Cutting means moving
something (file, folder, text, image, etc.). Pasting is the action of bringing the cut
item in its new location.

To cut a file or folder

Right-click on the file or folder that you
want to move.
A pop-up menu appears. Click on Cut.
or
Select the file or folder that you want to
move.
Press on Ctrl+X.

Paste the file to a new location.

Open the desired folder where you want to move the
file or folder.
Right-click on the blank area.
Click on Paste from the pop-up menu.

or
Select the file or folder that you want to move.

Press on Ctrl+V.

Copying a File or Folder

Like cutting, copying is also a common function in
Windows. Copying creates a duplicate item.

To copy a file or folder

Right-click on the file or folder that you want to move.
A pop-up menu appears. Click on Copy.
or
Select the file or folder that you want to move.
Press on Ctrl+C.

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Paste the file to a new location

Open the chosen folder where you want to copy the file or folder.
Right-click on the blank area.
Click on Paste from the pop-up menu.
or
Select the file or folder that you want to move.
Press on Ctrl+V.

Running different programs in Windows

Windows provides many additional apps that help us in performing various tasks.
Some important apps in Windows 10 are as follows:

Calculator

You can perform different arithmetic and scientific calculations from this app.
To run Calculator

Press on Windows Key and on R at the
same time.
Run window appears.
Type ‘calc’ as shown in the figure alongside.
Finally, click on the OK button.
The Calc app runs.

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Notepad

It is a simple text-editor program.
Type “notepad” in Run Window to use this app.

On-Screen Keyboard

This app allows you to type without a physical keyboard.
To run On-Screen Keyboard

Press on Windows Key and R at the same time.
Run window appears.
Type ‘osk’ as shown in the figure alongside.
Finally click on the OK button.

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The On-Screen Keyboard app runs.

Magnifier

This app is used to magnify (enlarge) the screen.
To run Magnifier tool

Press on Windows Key and on R at the same time.
Run window appears.
Type ‘magnify’ as shown in the figure alongside.
Finally, click on the OK button.

The Magnify tool appears on the screen.
Press on + or – button to Zoom In or Zoom Out the current screen.

2) Utility Software

A utility (also known as service program, service routine, tool, or utility routine)
is a program that makes the computer system easier to use or performs highly
specialized functions. Utility softwares are used to manage disks, troubleshoot
hardware problems, and perform other tasks that the operating system itself
may not be able to do. Examples of utility software are: disk defragmenters, virus
scanners, archive, registry cleaners, network managers like (NAV, Kaspersky,
Winzip, WinRar, etc.)

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3) Language Processors

Language translator or language processor is a type of system software that
translates programs prepared by programmer in any other languages into machine
language. It converts the programming instructions written in human convenient
form into machine language codes that computers understand and process. The
programs written in any programming language need to be converted to binary
form using language translator. There are three types of language translators.
They are:

i. Assembler ii. Interpreter iii. Compiler

i. Assemblers

Computer programmers started using text codes instead of binary codes to
make programming easier. They started using codes called mnemonics which are like
mov (move), int (interrupt), jnz (jump not on zero), etc. The programming language
which uses mnemonics is called Assembly Language. An Assembly Language
program cannot be executed by a computer’s processor because it understands
only machine language. The program written in Assembly Language should be
converted into machine language program (also called machine code). Software
called Assembler is used to translate Assembly Language program into machine
code. Assembler software is available in the market from different companies like
Microsoft Assembler (MASM), and Turbo Assembler (TASM). Machine Language
and Assembly Language are called Low Level Language. These languages interact
with the computer’s hardware directly. This makes them powerful but difficult:
powerful because they can do everything possible in a computer as they interact
with the hardware parts directly and difficult because the programmer has to
possess in-depth knowledge about all the hardware of a computer. Programs
written in Low Level Languages are called machine dependent because the
program written for a machine with one type of hardware does not work in another
machine with different type of hardware.

ii. Interpreters

An interpreter is a type of language translator that translates program
written in high level language (human language) into machine language line by
line or statement by statement. Only after the translation of first statement of
the program, it translates the next statement of the program and so on. In other
words, an interpreter translates a statement in a program and executes the
statement immediately before translating the next source language statement.
While converting of the statement, if any error occurs, it immediately shows the

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error message and terminates the execution of the next statement. Some of the
programming languages such as GWBASIC, QBASIC, LISP, LOGO, etc. use
interpreter language translator.

iii. Compilers

A compiler is a type of language translator which translates high level code
into machine code at once and saves in a binary file. The translated binary file
is called an object file. The object file is linked with library modules and other
required modules to make an independent executable file. These executable files
can be executed in the future without the compiler or the source code. Some of the
programming languages such as C, C++, Visual Basic, Java, FORTRAN, etc.
use compiler as a language translator.

High Level compiler Object File linker Executable
Language (translated binary program

Code file)

Library and
other modules

Device Drivers

The operating system often provides programs for working with special devices
such as printers. These programs are called drivers because they allow the
operating system and other programs to activate and use, “drive” as the hardware
device. Most new software you buy will work with your printer, monitor, and other
equipment without requiring you to install any special drivers because device
drivers for common peripherals are already included in the OS.

Application Software

Application software is a type of computer software designed to solve a specific
problem in a specific time according to instruction provided by user. It is a set of
an organized program developed to perform a specific data processing jobs such
as preparing documents, accounting ledgers, bills, playing music, displaying
result of exams, manipulating graphics, etc. for the user. It can manipulate text,
numbers, graphics, and a combination of these depending on the work for which it
was developed. Application software is designed by focusing for all general people

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or for a person, company or organization. Some examples of application software
are word processors, spreadsheets, database, accounting, web browsers, payroll
programs, communication programs, multimedia programs, graphics programs,
etc. There are two types of application software. They are:

i. Packaged Software ii. Customized or Tailored Software

Packaged Software

Packaged software is a type of
generalized set of application
software that allows the computer
to perform specific task for different
users. It is user friendly ready-
made program designed to meet
the common requirements of a wide
variety of users for particular type of
work in more than one environment.
Some examples of the most commonly used packaged software are: word processing
software, spreadsheet software, presentation software, database software, graphics
software, multimedia software, accounting software etc.

Customized or Tailored Software

If none of the available application software packages meets the specific
requirements of a user (an organization or an individual), it becomes necessary
for the user to create a customized software package. A Tailored or Customized
application software is the software developed by the programmers using high
level languages such as Visual Basic, C#, Java, ASP.Net, SQL Server, Oracle, PHP,
etc. to meet the specific requirement of an individual or organization. Examples
of customized software are banking software, hotel management software, school
management software, etc.

Open Source Software/ OSS

Open Source Software (OSS) is computer software in which the source code is
freely available to the general public for redistribution, modification, examination
or any other feasible purpose. It is available in source code format free of cost.
The distributions of open source software expect and encourage users and outside
programmers to examine the code in order to identify problems and to modify the
code with suggested improvement and enhancements. The users get the freedom
to run the open source software for any purpose and redistribute copies of either

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the original or modified form. It is usually created as a collaborative effort in which
programmers improve upon the code and share the changes within the community.
Open Office, VLC, Mozilla Firefox, MySQL, Miro Video Converter, X-Chat2, PealZip
(zip software), ZScreen (screen-capture software), Linux are the examples of open
source software.

Open Source Software

Desktop Application and a Web Application

A desktop application is a computer program that runs locally on a computer device,
such as desktop or laptop computer which could be used on standalone machines
only. Desktop applications have traditionally been limited by the hardware on
which they are run. They must be developed for and installed on a particular
operating system and may have strict hardware requirements that must be met to
ensure that they function correctly. Updates to the applications must be applied by
the user directly to their installation and may require hardware upgrades or other
changes in order to work.

Desktop Applications

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However, with the advent of internet and online commerce, web application
development gained importance. Word processors, Spreadsheet, Media players can
be considered to be typical desktop applications, while an online shopping cart on
an e-Commerce website, e-banking can be considered as a web application. Some
desktop applications can also be used by multiple users in a networked environment.

Web Applications

Web application development, however, soon started replacing desktop applications
for reasons of portability and better functions from the point of view of utility.
Web application development is usually made on a client-server architecture and
use a web-browser as the client interface. The user accesses the application using
the web and works with resources available over the internet, including storage
and CPU processing power. This approach allows for “thin clients” (machines with
limited hardware capabilities) to provide access to complex applications delivered
from a centralized infrastructure.

Mobile Apps

Applications specially designed and developed to
run on smartphones, iPad and tablets are called
Mobile Apps or simple apps. These applications
are developed for various purposes like gaming,
entertainment, productivity, etc. Typically these
apps are hosted on a common platform called App
Store (in case of Apple or iOS users) or Google Play
Store (in case of Android users) or Windows Store
(in case of Windows or Microsoft users). You can find
millions of apps on these platforms and download
apps of your interest either free or by paying Mobile Apps

required amount. Depending on purposes, some of these apps are standalone or
Internet dependent. Clock App, FM Radio App, Camera App, etc. do not require
Internet Connection whereas Facebook, Viber, WhatsApp, etc. require Internet.

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Since number of smart phones have been increasing day by day and are always
carried by people, usability and accessibility of Mobile Apps are very high.
These days, more and more people access and use Internet via Mobile Apps like
Facebook, YouTube, Webchat, WhatsApp, Snapchat, Viber, HamroPatro, etc.
Every organization nowadays is trying to deliver their service to their customers
via Mobile Apps.

POINTS TO REMEMBER

The set of instruction or program written by using programming language to solve a
problem is called computer software.
The software that manages, controls and supports computer system is called system
software.
Operating system software manages, controls, and looks after overall operation of
computer.
The background area of the windows screen is called desktop.
Icons are the small picture buttons that represent file, folder, programs, etc.
Dialogue box appears to perform a task or command like file save, document print,
etc. to user in windows operating system.
A file is a set of related data and information stored on computer system.
Folder is a container to store file and sub folder.
Language processor converts high level language or assembly language into machine
level language and vice versa.
An assembler is a type of language processor which converts program code written
in assembly language into machine language.
The main objective of utility software is the smooth functioning condition of computer
system.
The application software is used to type e-mail, edit photos, make presentation,
listen to music, produce engineering design, video, and bills, etc.
Open source software is freely available software and source code is also available
free of cost.
The software which is proprietary or open source software available free of cost is
called freeware.

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Exercise

1. Fill in the blanks.

a. A set of .................. that drive a computer to perform specific tasks is called program.

b. Most softwares fall into .................. major categories.

c. .................. operating system allows computers to communicate and share data across
a network.

d. Examples of utility software are ..................

e. Machine Language and Assembly Language are called ..................

f. A .................. is software which translates whole high level code into machine code at
once.

g. An ........... translates high level language instructions one by one at the time of execution.

h. Electricity can have two district states ……..and ……….

i. ………………..or…………….are used to translate high level language codes into
machine codes.

j. ………….is called machine language.

k. ……………language is the mother tongue of the computer.

l. There are ………….types of applications software.

m. A……………..software is the software developed by the programmers using high
level languages.

n. Apple or iOS users apps are hosted on a …………………platform.

o. Android users apps are hosted on a …………………platform.

p. Windows users apps are hosted on a …………………platform.

2. Write the technical Terms of the following.

a. The invisible part of computer system which user cannot touch.
b. A set of program that controls and manages the overall operations of a computer.
c. Software that translates program written in high level language into machine language

line by line.
d. A computer program that allows other programs to interact with a hardware device.
e. Software that is designed for general user for common purpose.
f. System software designed to perform maintenance work on the computer system.
g. Freely available source code to the general public.

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3. Give full forms of the following abbreviations:

a. TASM b. MASM c. FORTRAN d. COBOL
h. GUI
e. BASIC f. OSS g. CUI

4. Choose the correct answer.

a. Software is collection of ……………..

i) instructions ii) unprocessed data

iii) programs iv) none of them

b) The special set of program files of a device.

i) Device Driver ii) Utility Software

iii) Operating System iv) Language Translator

c) Software that translates program written in high level language into machine language
at once.

i) Assembler ii) Interpreter

iii) Compiler iv) None of them

d) Software that serves as an intermediary between user and computer system.

i) Operating System ii) Application Software

iii) Utility Software iv) Language Translator Software

e) A specialized set of program that performs specific task for an organization.

i) System Software ii) Packaged Software

iii) Customized Software iv) None of them

f) Computer software in which the programming code is free for people to view, modify,
and build new software.

i) Utility Software ii) Open Source Software

iii) Application Software iv) Device Driver

5. Answer the following questions:
a. Define hardware and software.
b. How many types of software are there? Write two examples of each.
c. Define and distinguish between application software and system software.
d. Explain the importance of system software for a computer system.

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e. What is a utility program? List some tasks commonly performed by utility programs.
f. How does a normal user interact with the hardware of a computer? Describe the various

in-between layers.
g. What is open source software (OSS)?
h. Differentiate between compiler and interpreter.
i. Why does a computer system need application software?
j. Differentiate between packaged and tailored software.
l. Why is tailored software demanded by the user or an organization?
m. What are web applications?
n. Give any two differences between desktop applications and web applications.
o. What are mobile apps? Give any four examples.
p. Why are mobile apps very popular nowadays?

6. Classify the following software into Application and System.

MS-Windows, MS-Word, MS-Excel, Unix, MS-Access,
Internet Explorer,
Linux, Photoshop, Dream weaver, WinZip, 3D Studio Max,
Acrobat Reader.
Kaspersky, Power DVD, AutoCAD, Maya,

Mac O/S, Windows 10, Red Hat, Flash,

Activities

1. Draw in chart paper the different types of computer hardware with name and paste
in your classroom.

2. Name one useful open source softwares that you are familiar with. List its features
and prepare a presentation.

3. Take a short interview with your teachers, friends, parents, and relatives. Prepare a
field report about what types of computers, laptops or other devices they are using.
And what types of operating system the device has. Also, make a list of apps that
they have used in their smartphones and present in your classroom.

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Group

B

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Unit

2

Chapter Includes:

Different Graphics Format
Graphics for Web
Image Size and Resolution
Graphic Editing

Introduction

A graphic is an image or visual representation
of an object. The term "Graphics" is derived
from the Greek word 'graphikos', which means
'something written'. Such visual images that
are generated by a computer are called computer
graphics.

Computer graphics are simply images
displayed on a computer screen. It includes
everything that is presented through images
developed or designed using different graphical
software. Graphic design is a means of visual
communication. As you have heard an English
language idiom "A picture is worth a thousand
words," with a good graphical design, you can
express your message more effectively and beautifully. Our brain process visual
information so much more effectively and quickly than textual information.
Therefore, graphics is a very important communication component in present days.

Computer graphics is the discipline of generating images with the aid of computers.
Today, computer graphics is a core technology in digital photography, film, video
games, cell phone and computer displays, and many specialized applications. In
previous grades, you have worked on MS-Paint and Adobe Photoshop. You can
draw and edit pictures with these graphical softwares.

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Some popular image editing software are:
Adobe Photoshop
GIMP (GNU Image Manipulation Program)
Adobe Illustrator
CorelDraw
Paint.net

The term “Computer Graphics” was
first used by William Fetter, Graphic
Designer of Boeing Company in 1960.

2.1 Different Graphics Format

Image files are composed of digital data. Graphic formats are the standards
used for organizing and storing digital images. Basically, there are two types of
graphics format.

a. Raster Format Raster Format

Raster graphics are the most common type of image
files. Raster format (also called Bitmap images) are composed
of tiny squares called pixels (px), and each pixel is assigned a
specific color. Pixel is the smallest element of a raster image.
In digital imaging, a pixel (short for Picture Element) is the
smallest addressable element of a picture represented on a
screen. The number of pixels determines the image quality.

b. Vector Format

Unlike raster format, vector images are not
composed of pixels. This format is most commonly
used for creating logos, illustrations, and print
layouts. Digital information is stored using some
mathematical formulas that establish points on
a grid in a vector image. The main features of
vector graphics are that its quality remains same
when you enlarge it to any size.

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Differences between raster and vector graphics:

Raster Graphics Vector Graphics
Vector graphics are composed of
Raster graphics are composed of paths, or lines.
pixels. Vector images can be enlarged
without losing quality.
Raster images get blurry when they Vector images occupy less space.
are enlarged.
Highly applicable for drawing
Based on quality, raster images Suitable to design logos
occupy more space. Popular Vector Graphics Editors:
Adobe Illustrator, CorelDraw
Highly applicable for painting
Common file extensions: AI, PDF,
Suitable for web graphics SVG, EPS

Popular Raster Graphics Editors:
Adobe Photoshop (has limited vector
capability), GIMP

Common file extensions: JPG, GIF,
BMP, TIF, PNG

Note: - Joint Photographic Experts Group
- Bitmap
JPG - Graphics Interchange Format
BMP - Tagged Image Format
GIF - Portable Network Graphics
TIF - Adobe Illustrator
PNG - Scalable Vector Graphic
AI - Encapsulated Post Script
SVG - Portable Document Format
EPS
PDF

2.2 Graphics for Web

Graphics adds visual appeal to the information, which is vital to web design.
Web graphics includes illustrated images, infographics, charts, graphs, animated
graphics, and photographs. Good graphic design increases the usability of your
site. Graphics is used to communicate or explain ideas visually.

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Things to be considered while using web graphics:
Graphical content should be used with purpose.
Do not use graphics with large file size. It consumes more bandwidth.
Always use graphics, relevant to the content.
Crop the unwanted part of the graphics.
Balance the graphics with background and text color.

Some Popular Graphical Software for Web Design:
Adobe Photoshop, and GIMP for raster graphics. They also provide limited
features of handling vector graphics.
Adobe Illustrator, and CorelDraw for vector graphics.
Google Photos, Pixlr, Befunky, Fotor, PicMonkey, Photoshop Express, and
iPiccy are some popular online photo editors.

Web Graphics Format

The primary web graphics format are gif, jpg, and png. All these common web
graphics format are called bitmap graphics.

JPG Graphics

JPG is the most common image format used in web.
Usually digital cameras take images in JPG format.
It is suitable for images with a lot of different colors like photographs.

GIF Graphics

GIF is the second most common image format used in web.
Suitable for images that require a few distinct colors such as line drawings,
logos, b/w images, or images with few colors.

PNG Graphics

Newest file format.
Better compression and transparency features than GIF.

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jpg gif png
Graphic Interchange
Full Form JPEG - Joint Format Portable Network
Photographic Experts gif or jif Graphics
Group Yes
ping
Pronounced as Jay Peg 256 Yes
PNG – 8 (256)
Support Transparency No Yes
Lossless PNG – 24 (16
Maximum Color 16 Million Million)
Supported No

Animation Supported No Lossless

Compression Lossy
Technique

Not Transparent Image Transparent Image supported by GIF and PNG

Compression techniques

Lossy Compression

In lossy compression, the compressed file cannot be brought back to its original
form. JPG supports lossy compression.

Lossless Compression

In lossless compression, the compressed file can be decoded back into its original
form with zero loss of information. PNG and GIF supports lossless compression.

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2.3 Image Size and Resolution

Image size refers to the length and width of a digital image. In the given
figure, the dimension of the image is given as 3264x1836. It means:

The image width is 3264
pixels.
The image height is 1836
pixels.
Therefore, the total number
of pixels that made the given
image is:

3264 ×1836 pixels = 5,992,704 pixels

To check the image size Image File Metadata

Step 1 : Right Click on the image file from its folder. A pop-up menu
appears.

Step 2 : Click on Properties.

You need to change the image size depending on your purpose of using the particular
image. For example, you have high-quality photograph, which you want to publish
on a web page. Then you need to lower the image size to decrease the download
time for your web site visitor. Likewise, if you have to print the image file, you
should have high-quality image.

Resolution What is a megapixel?

Resolution refers to the Technically, a megapixel is equal to 1,048,576 pixels but
number of pixels in an the camera manufacturing company round this figure
image. The greater the to 1,000,000 (1 million). Therefore, 1 million pixel is
number of pixels, the equivalent to 1 megapixel.
higher the resolution,
provides more details and If you have 12 megapixel camera, then the photo it takes
better definition to the can have maximum 12x1,048,576 (12,582,912) pixels if
image. the aspect ratio of your camera is 3:2. Approximately,
each full size of raw image taken by 12MP camera is
The most common units 4344 x 2896 pixels in dimension. So, by multiplying the
to measure resolution are number of pixels along the width by those of the height
PPI (pixels per inch) and (4344 x 2896 = 12,580,224 – rounded to 12 million
DPI (dots per inch). pixels), we get the actual number of pixels in the image.

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PPI – It refers to the number of pixels per inch that makes an image. It affects the
print size and quality of an image.
For Example: resolution – 96 pixels/inch

1 inch – 96 pixels

Total number of pixels per square inch = 9,216 pixels (96 pixels x 96 pixels)
In the same way, if the resolution is 300 pixels/inch, the number of pixels per
square inch will be 90,000 pixels.
DPI – It only refers to a printer. It indicates the number of physical dots of ink in a
printed document. For example, 1200 dpi printer uses 1200 dots of ink in every inch
to make up the colors.
Image resolution controls the print size of an image. The resolution sets the number
of pixels that are printed per linear inch of paper horizontally and vertically.

Calculating Print Size

6.18 inch

12.5 inch

Image Dimension – 900 x 445 pixels
Resolution: 72 pixel/inch

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Width of actual print size = 12.5 inch (900/72)
Height of actual print size = 6.18 inch (445/72)
Therefore, the given image takes the area of 12.5 by 6.18 inch of paper while
printing. This is also called document size.
Major considerations:

Optimize the file size of your image. Do not place large size image unnecessarily.
Choose the suitable format (jpg, gif, png) for your webpage.
Place the image at the appropriate place of your webpage.
Set the appropriate width and height of image proportionately.
Number of pixels determines the size of image.
Generally, resolution sets the print size of an image.
Image size refers to the pixel dimension of an image not its size in Bytes or
KB.
File size of image (in Bytes or KB) varies with image content and compression
techniques.

2.4 Graphics Editing

Graphics is a vital component for expressing ideas and information in the
web site. Therefore, one of the core skills of a web designer is a good knowledge of
graphics editing. There are many graphics editing application software available to
design and edit web graphics. In this lesson, some basic image editing techniques
are discussed using the most popular photo-editing tool – Adobe Photoshop.

Adobe Photoshop

Adobe Photoshop is a raster graphics editor developed and published by Adobe Inc.
It was originally created in 1988 by Thomas and John Knoll. Most of the graphic
designers, web designers, graphic artists, photographers, and creative professionals
use this popular tool.
Adobe Photoshop is very popular software because of its different image editing
and retouching effects. Adobe Photoshop allows users to manipulate, crop, resize,
correct color, apply effects, add text, and many other editing tasks.

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To start Photoshop

Step 1 : Open the Run Window.

Step 2 : Type Photoshop.
Step 3 : Press on Enter or Click on OK.

[If Adobe Photoshop is installed in your computer, Photoshop starts.]

Photoshop Workspace

Menu Bar

Tools Panel Options Bar

Palettes

Document Window/Canvas
Photoshop Workspace

Menu Bar

Menu bar contains the File, Edit, Image, Layer, Select, and other menus, which
provide you a variety of image editing commands, adjustments, and panels.

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Document Window/Canvas

Document Window or Canvas displays the graphic file you are currently working
on. You can open multiple image file in the workspace.

Tools Panel

Tools Panel contains a variety of tools for editing images and creating artwork.
Similar tools are grouped together.

Options Bar

Options bar provides you the different options for the tool you are currently working
with.

Palettes

Palettes include color, layers, character, and other necessary palettes, which
provides you a variety of related controls for working with images. You can add
other palettes in the workspace from the Windows menu.

Opening an Image File

Follow the steps to open an image file:
Step 1 : Click on File Menu > Open … (Keyboard Shortcut: Ctrl + O)

An open dialog box appears:

Step 2 : Select the folder of your image file.
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Step 3 : Select the required image file.
Step 4 : Click on Open button.

Changing the Image Size

Follow the steps to change the image size:
Step 1 : Open the required image file.

Step 2 : Click on Image Menu > Image Size…
(Keyboard Shortcut: Alt+Ctrl+I)
An Image Size dialog box appears:

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Step 3 : Here, the size of image is 900x900 pixels. Print size is 12.5 by 12.5
inch and the resolution is 72.
Type the required width and height in the pixel dimension section.

Note:

In the above dialog box, Constrain Proportions is checked. It means if you enter the value of
Width, the value for Height is proportionately set.

Step 4 : Change the value of width and height in document size section if
you want to print it.

Note:

Think about the resolution of image. The output will come in low quality if you increase the
size of low-resolution image.

Step 5 : Click on OK button to accept the changes.

Changing the Image Format

Follow the steps to change the image format:
Step 1 : Open the required image file.
Step 2 : Click on File Menu > Save As… (Shortcut Key: Shift+Ctrl+S)

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A Save As dialog box appears:

Step 3 : Type name in filename drop-down list box if you want to give
another name.
Step 4 : Select the target folder if you want to save in another location.
Step 5 : Select the file format that you want to change.

Step 6 : Click on Save button.

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Creating a new image file

Follow the steps to create a new image file:

Step 1 : Click on File Menu > New… (Shortcut Key: Ctrl+N)
A New dialog box appears:

Step 2 : Type the required value for width, height, and resolution of your
page.
Step 3 : Select Color Mode and background contents.
Step 4 : Click on OK.
Now, a blank image file appears on the workspace.

Tools Panel

This palette contains some groups of tools that are used to edit and manipulate
images. Here, text tool and some selection tools of tools panel are discussed below:

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Rectangular Marquee Tool (M) Move Tool (V)
Lasso Tool (L) Magic Wand Tool (W)
Crop Tool (C) Slice Tool (K)
Brush Tool (B)
Spot Healing Brush Tool (J) History Brush Tool (Y)
Clone Stamp Tool (S) Paint Bucket Tool (G)
Eraser Tool (E) Dodge Tool (O)
Blur Tool (R) Horizontal Type Tool (T)
Pen Tool (P) Rounded Rectangle Tool (U)
Eyedropper Tool (I)
Path Selection Tool (A) Zoom Tool (Z)
Notes Tool (N)
Hand Tool (H) Background Color

Foreground Color

Edit in Quick Mask Mode (Q)
Jump to ImageReady (Ctrl+Shift-M)

Tools Panel

Note:
The character in the bracket in Tools Panel is shortcut key to activate the required tool. For
example, press V to activate Move tool.

Type Tool

The Type tool is used to add text to your image file. You might have to add text
while creating poster, invitation, or any other graphical design. You can also apply
different effects to text in Photoshop.

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Adding Text

Follow the steps to add text over an image:

Step 1 : Create a new file or open an existing image file.
Step 2
: Click on Type tool from Tools panel or simply press “T”.

The Type tool is activated.

Various Options related with text appear in the Options
Bar.

Set the font family Set the font size Set the text colour

Step 3 : Options bar of Type Tool
Step 4 :
Choose the target font, text size, and color.
Click and drag anywhere in the workspace (new image or existing
image) window to create a text box.

A new text layer is added to your image.

Text layer

Step 5 : Text Box over the image

Type the required text.

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Moving Text
Select the text layer.
Select the Move tool or press on V.
Click on and drag the text to the
required location.

Edit the Text
Double-click on the layer icon of
the required text.
or,
Select the type tool and click on
the text.
The text is highlighted.
Now, you can modify the text, text size, and color

Selection Tools

The selection tools are what you use to select portions of an image to edit. Selection
tool is one of the mostly used tools in Photoshop while manipulating or designing
images. These tools are used to isolate different part of an image so that we can
work only on that particular area without affecting the rest of the image.

Marquee Tool

The Marquee tool is the most basic
of selection tools and often the one
most useful. This tool is used to draw
selections based on geometric shapes.
Specifically, the marquee tool allows
you to draw rectangular and elliptical
selections.

Follow the steps to select a part of an image using the Marquee tool:
Step 1 : Open a required image file.
Step 2 : Select either Rectangular or Elliptical selection tool.

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Step 3 : Click on and drag over the area of the image you want to select.

Note:

Hold down shift button while dragging to constrain the marquee to square or circle.
You can cut, copy or apply some other effects on the selected portion of the image.

Lasso Tool

Lasso Tool allows the user to draw freehand selections
around objects. Besides the standard Lasso tool,
Photoshop provides two other types of Lasso tools:
Polygonal Lasso Tool and Magnetic Lasso Tool.

Follow the steps to select a part of an image using the Lasso tool:

Step 1 : Open a required
image file.

Step 2 : Select the Lasso
Tool.

Step 3 : Click and drag to
draw a freehand
selection border
over a targeted
part of the image.

Step 4 : Release the
mouse button.

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Polygonal Lasso Tool:

The Polygonal Lasso tool allows the user to draw straight-edged segments of a
selection border.

Follow the steps to select a part of an image using the Polygonal Lasso Tool:

Step 1 : Open a required image file.
Step 2 : Select the Polygonal Lasso Tool.
Step 3 : Click on the required point on the image to set the starting point.
Step 4 : Move the cursor to the
next point not far from
Step 5 : the starting point and
click the left button
again. A selection
path is drawn between
these two points.
Keep putting points in
the same way until the
target area is outlined.

Note:

To draw a straight line at a multiple of 45°, hold down Shift as you move to click the
next segment.

To draw a freehand segment, hold down Alt and drag.

To erase recently drawn straight segments, press on the Delete key.

Magnetic Lasso Tool:

It is an edge selection tool that detects an image's edges and automatically selects
the pixels around them. This gives it a high degree of precision, particularly if
there is some contrast between image and the background.

Follow the steps to select a part of an image using the Magnetic Lasso tool:
Step 1 : Open a required image file.
Step 2 : Select the Magnetic Lasso Tool.
Step 3 : Click on the required point on the image to set the starting point.
Step 4 : Release the mouse button or keep it pressed, and then move the

Approved by Curriculum Development Centre, Sanothimi, Bhaktapur 100