comp

Ø Expansion Slots and cards :



Graphic Card

A graphic card is an expansion card whose function is to generate output
images to a display.

Modem

A modem is a device or program that enables a computer to transmit data
over telephone or cable lines.

Sound Card

A sound card is an expansion board that actually is an audio processor
consisting ADC and DAC unit in it. It is used to manipulate sound input and
outputs.

Network Card

NIC is a computer circuit board that is installed in a computer. It provides
the point where we plug in the Ethernet cable so that computer can become the
part of network. It contains electronic circuitry that enables a device to
communicate using a wired or wireless connections.

NIC is a computer hardware component that connects a computer to a computer
network. It also boosts or amplifies the signal’s strength.

Ø Computer Power Supply : The computer power supply is a metal box

inside the system unit that safeguards the PC components by converting

high voltage current to low voltage current. It converts the electric current
from source to correct voltage and frequency to power the load. It is designed
to convert 110 V or 230 V AC power from the mains to several low voltage
DC power outputs for the internal components of the computer.

Ø Exhaust Fan : Exhaust fan is a component of a system unit

responsible for cooling down the power supply device. It prevents the system

from getting overheated.

Ø Buses : Buses are sets of wires that facilitate the communication
between different components of a motherboard.

Types of Buses

i. Data Buses : The group of wires that carry data from RAM to
microprocessor and back and also carry instruction from ROM to RAM
for execution are called data buses.

ii. Address Buses : They carry the memory address of data sent through
data buses and address of the I/O devices.

iii. Control Buses : The CPU transmits a variety of control signals to
different components and devices also transmit control signals to the
CPU. It is done by using control signals.

Computer Software






A computer is merely a machine that knows nothing by itself. Rather
it requires clear-cut instructions for each and everything it performs. A set of self-
contained instructions that tells a computer how to solve a problem or carry out a
task is called a program. A group of such programs that are put into a computer
to operate and control its activities is called a software. It instructs the different
hardware units what to do and how to do. Software utilizes the hardware
performs the sequence of actions. So basically software contains huge number of
data and instructions arranged in a systematic order. Without software hardware
can not operate. It is the abstract part of the computer system that enables the
different hardware devices carry out input, processing and output operations.
At the very basic level, computer software consists of a machine language that
consists of groups of binary values, which specify processor instructions. The
processor instruction changes the state of hardware in a predefined sequence.

Computer Software is a collection of related programs along with all the necessary
data, information and documents that helps us to perform various task on a
computer system.

Program Software

• It is the set of instructions to • It is collection of instructions,
perform a specific job. program and data.

• It is component of software. • It is a logical unit which drives
the computer system.
• It defines process in the
computer. • It defines both process and data.

• Eg: a program to calculate SI, • Eg: MS Word, Adobe Photosoph
area of circle etc. etc.

Computer software can be classified into two types as:

1. System Software
2. Application Software

1. System Software

The software that activates the computer system and provide
operating environment to application software is called system software. It acts
as the bridge between computer hardware and application software. It controls
and manages all the resources and operations of a computer system. System
software is the collection of operating system, device drivers, language
processors and utility software.

It deals with the physical complexities of computer hardware and provides
the environment for executing application program.

v Operating System :
An operating system is the most important software that runs on a

computer. It is a system software that controls and coordinates the internal
working of the computer and performs a large number of functions which are
essential to operate the computer system. OS is a group of software that manages
all the computer resources and its operations. It acts as interface between the
users and hardware. It is the first program that is loaded into the computer by a
boot program and remains in main memory at all times. Hence, we can say that
OS is the soul of the computer system without which computer hardware becomes
functionless.

Examples : Windows, IOS, Android OS, Linux, Unix etc.

An operating system is a collection of programs designed to control the
hardware of a specific data-processing system in order to allow users and
application programs to make use of it.

Functions of Operating System

i. Booting the computer system.
ii. The operating system provides the basic interface (communication link) to

the user to work on computer. It receives commands from the users and
executes them.
iii. The operating system manages all the hardware devices of a computer.

Ø It recognizes inputs given by input devices.
Ø It manages RAM space to load multiple programs.
Ø It accesses files and programs to and from the storage devices.
Ø It allocates the CPU to a process and de-allocates processor when a

process is no longer required.
Ø It sends output to the monitor and other output devices.

iv. The operating system provides the platform on which other software are
executed.

v. An operating system allows to maintain data security management and
file management.

vi. Prevents the deadlock situation.
vii. Handles the interrupt.

v Device Driver :

A device driver is a small piece of software that tells the operating
system and other software how to communicate with a piece of hardware. Every
hardware attached to the computer system has its device driver installed, which
activates and introduces the hardware to the computer system.

It enables the operation of numerous devices including mouse, keyboard,
printer, video card and CD-ROM drive etc. by translating commands from
operating system or the user into commands understood by the associated
component. It also translates the response from the component back to the OS,
software application or user.

v Utility Software :

Utility software is designed to analyze, configure, optimize, manage
and maintain the computer resources. It helps the end users manage and tune
the relationship between hardware and software so that they keep running at
peak performance. Many OS have utility programs built in directly into the OS
itself. Other utility programs are available separately as software package
users must install. It is the system management tool.

Some examples of utility programs include :

Utility Software Description
Disk Defragmenter Fragmentation is a process that occurs in a computer’s
memory where the parts of same file gets scattered over
the different location. It happens while saving, modifying
or deleting the content of the files.
Defragmenter rearranges the fragmented files in the
continuous spaces on the disk. It reduces the data access
time and helps in efficient storage usage.

Scan Disk It helps to see if there are any potential problems on the

disk. If any errors are found, it will fix them. It also scans
the bad sector and try to recover them.

Backup Software It assists you in backing up your files and even the entire
computer hard drive.

Disk Cleanup It is a tool that inspects the hard disk and looks for the
files that can be safely deleted. Deleting unnecessary files
frees up the valuable disk space.

Antivirus It is a software designed to detect, identify and remove the
viruses and other malware from the computer system.

File Manager File manager or file browser is a computer program that
provides a user interface to manage file and folders.

Disk Partitioning Disk partitioning is the creation of one or more regions on
a hard disk or other secondary memory devices, so that an
operating system can manage information in each region
separately.

Disk Compression It is a software designed to organize or compress data to
maximize free disk space.

v

v

v Language Translator : Programming languages are the artificial

languages used to build computer programs. Machine language is the

language CPU understands which consists of the instructions composed

with 0s and 1s.

Language Processor is a special type of software that is used to

translate the programs written in high level and assembly level language

into machine level language. It also reports the errors in the program while

coding.

There are 3 types of language translators as:

i. Assembler
ii. Compiler
iii. Interpreter

Compiler Interpreter
§ It translates the whole program § It translates the program codes

at once. line by line.

§ Debugging is difficult. § Debugging is faster.
§ Program execution is faster. § Program execution is slower.
§ It generates object code. § It doesn’t generate object code.
§ C, C++ uses compiler. § QBasic, Python uses interpreter.

2. Application Software

Application software is a software designed to perform a specific
function directly for the user, in some cases, for another application. It enables
the users to accomplish a certain specific task. Application software is able to
manipulate the text, numbers and graphics to perform the job assigned by the
users.

Some Application Software are

Word Processing Software: MS-Word, Notepad, WordPad etc.
Database Software: MS-Access, FoxPro, Oracle etc.
Spreadsheet Software: MS-Excel, Lotus-123, Apple numbers etc.
Multimedia Software: VLC media player, Photoshop etc.

Types of Application Software are:

o Packaged Software
o Tailored Software

v Packaged Software :

It is a ready-made application program developed for sale to the
general public. It is targeted for a large audience. This kind of software are well
tested and contain very less errors. Packaged Software are very user friendly.
Eg: MS-Word, MS-PowerPoint, Oracle etc.

Special features of these generalized set of program :

Ø It should be user friendly.
Ø The package should have menu driven facilities.
Ø The user should be provided with the ‘HELP’ for technical support.
Ø The package should help the user in performing the task efficiently.

v Tailored Software :

It is a specific purpose software. Tailored made software is made as
per the specifications of a client. It is a custom made software to address the need
of the users. High level language such as C, C++, Java etc. are used to make
tailored software.
Eg: Hotel reservation software, School result processing software etc

Difference: Tailored Software

Packaged Software • It is specific purpose software.

• It is general purpose software. • It is expensive.
• It is cheaper, sometime free in cost. • It contains more errors.
• It is well tested and contain less error. • Ex: database management system for
• Ex: Microsoft office, Adobe Photoshop
schools, banks etc.
etc.

Difference: Application Software

System Software • It is designed to perform a group of
coordinated task for user.
• It is designed to provide platform to
other software. • It uses the services provided by the
system software to interact with the
• Manages resources and helps to run hardware components.
hardware and application software
• Runs when the user requires.
• Runs when the system start and runs
till the end. • It is machine independent.
• The programmer can ignore the
• It is machine dependent.
• The programmer must understand the architecture of the machine and
hardware details to write application
architecture of the machine and software.
hardware details to write system • Writing application software is easy.
software.
• Writing system software is complex.

Introduction to Open Source Software

Open source software is software whose source code is available and can
be customized and altered within the specified guidelines laid down by the
creator. It is free to use and the source code is available under a copyright
license to the public. They can use, modify or enhance the OS and redistribute.

Examples : Linux, Open Solaris, Free DOS, Apache OpenOffice etc.

Advantages :

i. It is available for free and redistribution may be available to do as per the
terms and conditions.

ii. It is a valuable learning opportunity for programmers. They can get the
source code, learn and also apply their own skills to the programs.

iii. Collective and collaborative efforts to the available open source programs
helps to build a more general and powerful programs.

Disadvantages :

i. Since open source software is free to use, there is typically no technical
support included with the software.

ii. Sometimes redistribution may be blocked.

Cloud App

A cloud app is an application that operates in the cloud. Cloud apps are
considered to be a blend of standard Web applications and conventional
desktop applications. A desktop app resides entirely on a single device at the
user’s location. A web app is stored entirely on a remote server and is delivered
over the internet through a browser interface. Cloud apps can provide offline
mode, rich user experience and instant responses to user actions. Cloud apps
also store data in the cloud.

Mobile Apps

An app is a small program distributed through app store that can be
downloaded and installed at once. Mobile apps are generally small, individual
software units with limited functions designed to run on a smart phone or
tablet computer. So mobile apps are hand picked by the users based on the
ability of their device. Different mobile apps are gaming apps, m-commerce
apps, productivity apps and lifestyle and entertainment apps.

Software Piracy

Software piracy is the unauthorized copying, redistribution, storage, use or
manufacture of software products.

Examples of software piracy

• Making and/or sharing copies of installation software.
• Sharing log in credentials used to access a web based software.
• Buying a single copy of a software program and installing it without

permission on multiple devices.
• Distributing software or mobile apps from the internet in a manner that

violates the license terms.

Differentiate :

Hardware Software

• Physical elements of a computer system. • A collection of instructions that tells
the computer how to perform a task.

• When damaged, it can be replaced with • When damaged, it can be reinstalled
a new component. using a backup copy.

• Developed using electronic and other • Developed by writing instructions
materials. using a programming language.

• It has four main categories: input • Mainly divided into system software
devices, output devices, processing and application software.
devices and storage devices.

Internet and Web Technology

The World Wide Web is the fastest growing part of the Internet. It is
a collection of millions of millions of files stored on thousands of computers (called
the web servers) all over the world. These files represent the text documents,
pictures, videos, sounds, programs and interactive environment. It is an
information-sharing model that is built on top of the internet. The flow of
information is controlled by protocol. The protocol used in this exchange is called
Hypertext Transfer Protocol (HTTP). The WWW gained its popularity largely
because it has a graphical interface and multimedia capabilities. The World Wide
Web was developed by British Physicist and computer scientist Timothy Berners-
Lee in 1989.

Internet :

Internet is the global network of computers providing a variety of information and
communication facilities. It is the network of networks that consists of millions of
private, public, academic, business and government networks that are linked by
a broad array of electronic and optical network technologies.
It is the largest computer network that connects billions of computer around the
world using TCP/IP. Internet is one of the most exciting and fastest growing
application of information technology. Its influence in our life is incalculable as it
has changed the way people work, communicate and do business. It has given new
interesting place to study, shop and socialize. It has shrunk the world and brought
people together giving existence to global village concept.

Web Technology :

Computers need directions and codes to function and communicate. Web
technology is the mechanism which enables the computers to communicate with
each other in the web. It includes markup languages and multimedia packages
computers use to communicate. Various web technologies are : browsers,
webpages, protocols, programming languages, databases etc.

To create a typical web page you need to combine 3 languages :

• HTML – The language for building the web pages.
• CSS – The language for styling web pages.
• JavaScript – The language for programming the behavior of web pages.

WWW :

It is the most popular service of the internet which gives access to the vast
array of information, files and software. WWW can be accessed by a special
software program called web browser using HTTP protocol. The web is the huge
collection of millions of web servers interconnected with each other. These web
servers store web sites of different topics or subjects. Each web site contains

visible and/or audible data presented using various multimedia components. And
every web site to access is specified by Internet Address or URL.

Web Page : A web page is a document on WWW, consisting of HTML file that

can be accessed from internet by going to its address. HTML file consists of group

of tags which specifies the web browser what and how contents are to be

displayed. Web pages can be either static or dynamic. Static web pages show the

same content each time they are viewed. Dynamic web pages have the content

that can change each time they are accessed. Web pages are requested and served

by using Hyper Text Transfer Protocol.

Website : A website is is actually a collection of files and documents which

is saved on the web servers. It is a set of interconnected web pages, usually

including a homepage, generally located on the same servers. Web sites are

prepared for communication purpose and to deliver information related to a

person, group or organization.

Web Server : A web server is a program residing on the main computer that
serves requested HTML files or web pages. A web server is connected to the
internet all the time. Every file has its own address called URL.

URL : Uniform Resource Locator is the global address of documents or
resources on the World Wide Web. It is actually a string of characters which
identifies the network resources on the Internet so as to retrieve the web pages.

Example:

https://www.facebook.com/lfesHomepage

Protocol Host Domain Name Filename

Domain Name : A domain name is the internet name of the computer that

is serving the information. It is a name used instead of IP address to represent

organization in the Internet. A domain name identifies the owner and type of the

resources or websites.

Example :

daraj.com.np

Domain Name Country level domain

Top level domain

Domain Name Server : DNS are the systems that maintain the directory of
domain names and translate them into IP address. DNS serves like a phone book
for Internet by translating human friendly computer hostnames into IP
addresses. For example, the domain name www.utsavblogs.com translates to
192.168.43.10 (IPv4) with the help of DNS.

DNS is necessary because, although domain names are easy for people to
remember, computers access websites based on IP addresses. Information from
all the domain name servers across the Internet are gathered together and housed
at Central Registry. Host companies and ISP interact with Central Registry
regularly to get updated DNS information. When you type in web address, e.g.,
www.myntra.com.in, your internet service provider views the DNS and converts
the domain name into IP address (for example 194.234.1.23) and directs your
request to the correct website.

Web Broswer : Web browsers are the “window to web” for the internet

users around the world. It is a program that allows the users to access web pages

and display its audible and visible data. It interprets the HTML code including

images, text, hyperlinks, JavaScript with the specific layout and design to give

information.

Ex: google chrome, mozila firefox, safari, opera mini etc.

When a user enters a URL, the web browser queries the domain name server and
gets the corresponding IP address of the desired machine. Web browser then
sends request to the connected router. The router then will scan the whole
internet map and find the best possible pathway to forward the request to desired
machine to access its resources.

Search Engine : Search engine is a website that collects and organizes different

websites and information from all over the internet. It simply is a program that
helps to search web documents on the basis of keywords entered by the users. It
locates the relevant information and list them down for the users, so data search
becomes easy and relatable to the users.

Examples : google.com, yahoo.com, Altavista, Britanica, bing.com,
Wikipedia.com etc.

IP address: It is a unique numerical identifier used for identifying a network

hardware that helps it connect it to the network. There are two versions of IP as:
IPv4 and IPv6.

Internet of Things (IoT) :

Internet of Things basically is a digital ecosystem created through the
interconnection of smart objects like mobile phones, laptop, smart watches etc.
IoT is the system of the interrelated computing devices, objects and people with
unique identifiers and ability to transfer data over a network without human-to-
human or human-to-machine interaction.

The “Internet” part of the term refers to mechanism for data
communication and “Things” part of the equation refers to growing number of
smart connected objects.
Cloud Computing :

The cloud is just an image of the internet. The cloud computing is the
practice of storing and accessing data and programs on a remote computer
using internet rather using your own local computer to do it. It is simply the
delivery of different services like data storage, data processing and technical
support and tools through internet. The practice of using a network of remote
servers hosted on the Internet to store, manage, and process data, rather than
a local server or a personal computer is known as cloud computing.

Hyper Text Markup Language

HTML is the most commonly used markup language to develop web pages. A web
page is simply an electronic document written using HTML tags. A markup
language provides a way to describe the structure and the behavior of information
on a web page. Hypertext is such a type of text that connects to other documents.

A hypertext document contains HTML tags and plain text.

Steps for developing web page :

Step 1 : Write HTML codes using any text editor such as Notepad, Sublime, VS
code.

Step 2 : Save the file using extension .html or .htm

Step 3 : Open the html file in web browser such as Internet Explorer.

HTML Tags :
A tag is a command i.e. sequence of characters enclosed within the angle bracket
< >. Tag specifies the web browser what to create and how to display the elements
of webpage.

< Element Attribute = “Attribute Value” >
For example :

< Body Bgcolor = “red” Text = “yellow” >
There are two types of tags as :

o Empty tags
o Container tags
HTML Structure : An HTML document has a fixed format for web design. An
HTML document should contain some standard tags. This format is known as
basic structure of HTML document.

<HTML>

<HEAD>

<TITLE>

Title of the webpage

</TITLE>

</HEAD>

<BODY>

Main content of the webpage

</BODY>

</HTML>

Different tags in HTML scripting language :

• <HEAD> tag : It includes the tags which builds the top section of the web
page. Header part of the webpage contains brand identifier, logo, menus and
search options.

• <TITLE> tag : It is a container tag which is used to mention the title of
the webpage.

• <BODY> tag : This tag is used to build the main section containing the
main content of the webpage.

Attribute Description

bgcolor Sets the background color, you can use color name or color code

background Sets picture as background.

topmargin Sets top margin of the page, in pixel.

bottommargin Sets margin at the bottom.

link Color of the hyperlink before clicking. Default : blue

vlink Color of the hyperlink after clicking it. Default : purple

alink Color of the hyperlink which are active. Default : red

• <BR> tag : It is a single tag which is used to break the line.
• <P> tag : This tag is used while writing the paragraphs of text.
Its has one attribute which is align.
• <HR> tag :
screen. <P align = “ left | right | center |justify”>
This tag is used to draw a horizontal line in the web page
Its attributes are :
width, size, noshade and color
Eg:

<HR width=”100%” color=”#ffffff” size=”5 px” >

• <Hn> tag : (Headline tag)

There are 6 size headline tags used to define different sizes of text in
the web page.

Input code :

<H1> Little Flowers’ English School </H1>

<H2> Little Flowers’ English School </H2>

<H3> Little Flowers’ English School </H3>

<H3> Little Flowers’ English School </H4>

<H4> Little Flowers’ English School </H5>

<H5> Little Flowers’ English School </H6>

Output :

Little Flowers’ English School

Little Flowers’ English School

Little Flowers’ English School

Little Flowers’ English School

Little Flowers’ English School

Little Flowers’ English School

Character Formatting Tags :

• <B> ….. </B> tag
• <I> ….. </I> tag
• <U> …. <U> tag
• <STRIKE> …… </STRIKE> tag
• <SUP> ….. </SUP> tag
• <SUB> ….. </ SUB> tag
• <BIG> …. </BIG> tag
• <SMALL> ….. </SMALL> tag
• <STRONG> …. </STRONG>

• <FONT>….. </FONT> tag : This tag is used to format the size, font

style and color of the text that is used in the web document.

Attributes :

o Face
o Color
o Size

Example :
< font face = “Arial” color = “red” size=”7” > Hey Dipsun Bhandari </font>

Output :

Hey Dipsun Bhandari

• <Marquee> tag : This tag is used to make the elements scroll and move
in the web page.

Attributes Description Values
1. behavior
It enables you to set the type of Scroll , Slide and

movement. Alternate.

2. direction It specifies the direction in which the Left, Right, Up and

text will move. Down.

3. bgcolor It specifies the background color. Any color

4. Scrolldelay It sets the amount of time between Integer values
each successive scrolling of marquee
text.

5. Scrollamount It specifies how many times to jump. Integer values

Example : will be shown practically.

• <IMG> tag : This tag is used to link the image in the webpage. Some
attributes that are used with <img> tag are :

src : to specify the pathname of the image file.
alt : to mention the alternative text.
height : to specify the height of the image.(in pixels)
width : to specify the width of the image.(in pixel)
title : to give title to the picture used.

• <video> tag : This tag is used to embed video content in a document like
movie clip or other video streams. Some of its attributes are :

src : to specify the source
height & width
controls : specifies whether video control should be displayed or not
like play/pause button.
autoplay : to specify whether to play video automatically or not. Its
value can be either True or False.