NCERT Textbook - Basics of Internet,Information & Computer Technology Class 9 | Information & Computer Technology (Class 9) - Notes & Video PDF Download

 Page 1


1
Chapter 1
Basics of Internet
Learning Objectives 
By the end of this chapter, learner will be able to:
• 	 De fine	 the	 In t erne t.
• 	 Lis t	 the	 f ea tur es	 of	 WWW .	
• 	 Diff er en tia t e	 be tw een	 the	 In t erne t	 and	 WWW .
• 	 Under s t and	 the	 w orking	 of	 Sear ch	 Engines.
• 	 Lis t	 diff er en t	 types	 of	 ser v er s	 with	 their	 purpose.	
• 	 Under s t and	 the	 diff er en t	 c omponen ts	 of	 a	 W eb sit e.
• 	 Appr ecia t e	 the	 use	 of	 diff er en t	 pr ot oc ols.
• 	 St a t e	 the	 adv an t ag es	 &	 disadv an t ag es	 of	 cr ea ting	 Blog ging.
IntroduCtIon
Today we live in a world of technology, where internet spins a web of interconnectivity 
around the globe. Through internet more than fifty million people in countries around 
the world have been connected. Internet was evolved in 1969, under the project named 
ARPANET(Advanced Research Projects Agency Network) to connect computers at different 
universities and U.S. defence. Soon after the people from different backgrounds such as 
engineers, scientists, students and researchers started using the network for exchanging 
information and messages. 
In 1990s the internetworking of ARPANET, 
NSFnet and other private networks resulted into 
Internet. Therefore, Internet is a ‘global network 
of computer networks’ . It comprises of millions 
of computing devices that carry and transfer 
volumes of information from one device to the 
other. Desktop computers, mainframes, GPS units, 
cell phones, car alarms, video game consoles, are 
connected to the Net. 
Page 2


1
Chapter 1
Basics of Internet
Learning Objectives 
By the end of this chapter, learner will be able to:
• 	 De fine	 the	 In t erne t.
• 	 Lis t	 the	 f ea tur es	 of	 WWW .	
• 	 Diff er en tia t e	 be tw een	 the	 In t erne t	 and	 WWW .
• 	 Under s t and	 the	 w orking	 of	 Sear ch	 Engines.
• 	 Lis t	 diff er en t	 types	 of	 ser v er s	 with	 their	 purpose.	
• 	 Under s t and	 the	 diff er en t	 c omponen ts	 of	 a	 W eb sit e.
• 	 Appr ecia t e	 the	 use	 of	 diff er en t	 pr ot oc ols.
• 	 St a t e	 the	 adv an t ag es	 &	 disadv an t ag es	 of	 cr ea ting	 Blog ging.
IntroduCtIon
Today we live in a world of technology, where internet spins a web of interconnectivity 
around the globe. Through internet more than fifty million people in countries around 
the world have been connected. Internet was evolved in 1969, under the project named 
ARPANET(Advanced Research Projects Agency Network) to connect computers at different 
universities and U.S. defence. Soon after the people from different backgrounds such as 
engineers, scientists, students and researchers started using the network for exchanging 
information and messages. 
In 1990s the internetworking of ARPANET, 
NSFnet and other private networks resulted into 
Internet. Therefore, Internet is a ‘global network 
of computer networks’ . It comprises of millions 
of computing devices that carry and transfer 
volumes of information from one device to the 
other. Desktop computers, mainframes, GPS units, 
cell phones, car alarms, video game consoles, are 
connected to the Net. 
2
Information and Computer Technology
1. World WIde Web
1.1 History of World Wide Web
The World Wide Web was invented by Tim Berners-Lee in 1989, in 1995 the first connection 
was established over what is today known as the Internet. 
By the end of 1990, the first Web page was served. In April 1993, the World Wide Web 
technology was available for anyone to use on a royalty-free basis.
Since that time, the Web has changed the world. It has perhaps become the most powerful 
communication medium the world has ever known. 
A global Web of computers known as the Internet, allows individuals to communicate 
with each other often called the World Wide Web. The Internet provides a quick and easy 
exchange of information and is recognized as the central tool in this Information Age. 
1.2 definition
The World Wide Web (WWW) is an internet based service, which uses common set of rules 
known as Protocols, to distribute documents across the Internet in a standard way. 
The World Wide Web, or ‘Web’ is a part of the Internet. The Web is viewed through web 
browser softwares such as Google Chrome, Internet Explorer, Mozilla Firefox etc. Using 
browsers one can access the digital libraries containing innumerable articles, journals, 
e-books, news, tutorials stored in the form of web pages on computers around the world 
called Web Servers. Today thousands of web pages/websites are added to the WWW every 
hour.
1.2 difference between Internet and WWW
The Internet is known as “interconnection of computer networks” . The Internet is a massive 
network of networks. It connects millions of computers together globally, forming a network 
in which any computer can communicate with any other computer as long as they are 
both connected to the Internet. Information that travels over the Internet does so via a 
variety of languages known as protocols.
The World Wide Web, or “Web” for short, or simply Web, is a massive collection of digital 
pages to access information over the Internet. 
The Web uses the HTTP protocol, to transmit data and allows applications to communicate 
in order to exchange business logic. The Web also uses browsers, such as Internet Explorer 
Page 3


1
Chapter 1
Basics of Internet
Learning Objectives 
By the end of this chapter, learner will be able to:
• 	 De fine	 the	 In t erne t.
• 	 Lis t	 the	 f ea tur es	 of	 WWW .	
• 	 Diff er en tia t e	 be tw een	 the	 In t erne t	 and	 WWW .
• 	 Under s t and	 the	 w orking	 of	 Sear ch	 Engines.
• 	 Lis t	 diff er en t	 types	 of	 ser v er s	 with	 their	 purpose.	
• 	 Under s t and	 the	 diff er en t	 c omponen ts	 of	 a	 W eb sit e.
• 	 Appr ecia t e	 the	 use	 of	 diff er en t	 pr ot oc ols.
• 	 St a t e	 the	 adv an t ag es	 &	 disadv an t ag es	 of	 cr ea ting	 Blog ging.
IntroduCtIon
Today we live in a world of technology, where internet spins a web of interconnectivity 
around the globe. Through internet more than fifty million people in countries around 
the world have been connected. Internet was evolved in 1969, under the project named 
ARPANET(Advanced Research Projects Agency Network) to connect computers at different 
universities and U.S. defence. Soon after the people from different backgrounds such as 
engineers, scientists, students and researchers started using the network for exchanging 
information and messages. 
In 1990s the internetworking of ARPANET, 
NSFnet and other private networks resulted into 
Internet. Therefore, Internet is a ‘global network 
of computer networks’ . It comprises of millions 
of computing devices that carry and transfer 
volumes of information from one device to the 
other. Desktop computers, mainframes, GPS units, 
cell phones, car alarms, video game consoles, are 
connected to the Net. 
2
Information and Computer Technology
1. World WIde Web
1.1 History of World Wide Web
The World Wide Web was invented by Tim Berners-Lee in 1989, in 1995 the first connection 
was established over what is today known as the Internet. 
By the end of 1990, the first Web page was served. In April 1993, the World Wide Web 
technology was available for anyone to use on a royalty-free basis.
Since that time, the Web has changed the world. It has perhaps become the most powerful 
communication medium the world has ever known. 
A global Web of computers known as the Internet, allows individuals to communicate 
with each other often called the World Wide Web. The Internet provides a quick and easy 
exchange of information and is recognized as the central tool in this Information Age. 
1.2 definition
The World Wide Web (WWW) is an internet based service, which uses common set of rules 
known as Protocols, to distribute documents across the Internet in a standard way. 
The World Wide Web, or ‘Web’ is a part of the Internet. The Web is viewed through web 
browser softwares such as Google Chrome, Internet Explorer, Mozilla Firefox etc. Using 
browsers one can access the digital libraries containing innumerable articles, journals, 
e-books, news, tutorials stored in the form of web pages on computers around the world 
called Web Servers. Today thousands of web pages/websites are added to the WWW every 
hour.
1.2 difference between Internet and WWW
The Internet is known as “interconnection of computer networks” . The Internet is a massive 
network of networks. It connects millions of computers together globally, forming a network 
in which any computer can communicate with any other computer as long as they are 
both connected to the Internet. Information that travels over the Internet does so via a 
variety of languages known as protocols.
The World Wide Web, or “Web” for short, or simply Web, is a massive collection of digital 
pages to access information over the Internet. 
The Web uses the HTTP protocol, to transmit data and allows applications to communicate 
in order to exchange business logic. The Web also uses browsers, such as Internet Explorer 
3
Basics of Internet
or Firefox, to access Web documents called Web pages that are linked to each other via 
hyperlinks. Web documents also contain graphics, sounds, text and video.
1.3 Search engines
Search engines are the programs which are needed to extract the information from the 
internet. They play a very important role in our daily routine, as today for each and every 
information we are dependent on internet. 
Web search engines work with the help of two programs, Spider which fetches as many 
documents as possible. Another program, called an indexer, reads the documents and 
creates an index based on the words contained in each document. Each search engine uses 
an algorithm to create its indices such that, only related results for specified keywords is 
stored and returns a list of the documents where the keywords were found. 
A search engine works in the following order:
 1. Web crawling: Web search engines work by storing information about many web 
pages. These pages are retrieved by the program known as Web crawler - which 
follows every link on the site. Web crawler may also be called a Web spider. 
 2. Indexing: Indexing also known as web indexing, it stores data to facilitate fast and 
accurate information retrieval. 
 3. Searching: A web search query fetches the result from the web search engine entered 
by the user to meet his information needs. 
Few search engines available are as follows:
2. Web ServerS
2.1 What is a Server?
A server is a computer that provides data to other computers. Th e entire structure of the 
Internet is based upon a client-server model. 
Web server helps to deliver web content that can be accessed through the Internet. The 
most common use of web servers is to host websites, as the internet is not only used to 
Page 4


1
Chapter 1
Basics of Internet
Learning Objectives 
By the end of this chapter, learner will be able to:
• 	 De fine	 the	 In t erne t.
• 	 Lis t	 the	 f ea tur es	 of	 WWW .	
• 	 Diff er en tia t e	 be tw een	 the	 In t erne t	 and	 WWW .
• 	 Under s t and	 the	 w orking	 of	 Sear ch	 Engines.
• 	 Lis t	 diff er en t	 types	 of	 ser v er s	 with	 their	 purpose.	
• 	 Under s t and	 the	 diff er en t	 c omponen ts	 of	 a	 W eb sit e.
• 	 Appr ecia t e	 the	 use	 of	 diff er en t	 pr ot oc ols.
• 	 St a t e	 the	 adv an t ag es	 &	 disadv an t ag es	 of	 cr ea ting	 Blog ging.
IntroduCtIon
Today we live in a world of technology, where internet spins a web of interconnectivity 
around the globe. Through internet more than fifty million people in countries around 
the world have been connected. Internet was evolved in 1969, under the project named 
ARPANET(Advanced Research Projects Agency Network) to connect computers at different 
universities and U.S. defence. Soon after the people from different backgrounds such as 
engineers, scientists, students and researchers started using the network for exchanging 
information and messages. 
In 1990s the internetworking of ARPANET, 
NSFnet and other private networks resulted into 
Internet. Therefore, Internet is a ‘global network 
of computer networks’ . It comprises of millions 
of computing devices that carry and transfer 
volumes of information from one device to the 
other. Desktop computers, mainframes, GPS units, 
cell phones, car alarms, video game consoles, are 
connected to the Net. 
2
Information and Computer Technology
1. World WIde Web
1.1 History of World Wide Web
The World Wide Web was invented by Tim Berners-Lee in 1989, in 1995 the first connection 
was established over what is today known as the Internet. 
By the end of 1990, the first Web page was served. In April 1993, the World Wide Web 
technology was available for anyone to use on a royalty-free basis.
Since that time, the Web has changed the world. It has perhaps become the most powerful 
communication medium the world has ever known. 
A global Web of computers known as the Internet, allows individuals to communicate 
with each other often called the World Wide Web. The Internet provides a quick and easy 
exchange of information and is recognized as the central tool in this Information Age. 
1.2 definition
The World Wide Web (WWW) is an internet based service, which uses common set of rules 
known as Protocols, to distribute documents across the Internet in a standard way. 
The World Wide Web, or ‘Web’ is a part of the Internet. The Web is viewed through web 
browser softwares such as Google Chrome, Internet Explorer, Mozilla Firefox etc. Using 
browsers one can access the digital libraries containing innumerable articles, journals, 
e-books, news, tutorials stored in the form of web pages on computers around the world 
called Web Servers. Today thousands of web pages/websites are added to the WWW every 
hour.
1.2 difference between Internet and WWW
The Internet is known as “interconnection of computer networks” . The Internet is a massive 
network of networks. It connects millions of computers together globally, forming a network 
in which any computer can communicate with any other computer as long as they are 
both connected to the Internet. Information that travels over the Internet does so via a 
variety of languages known as protocols.
The World Wide Web, or “Web” for short, or simply Web, is a massive collection of digital 
pages to access information over the Internet. 
The Web uses the HTTP protocol, to transmit data and allows applications to communicate 
in order to exchange business logic. The Web also uses browsers, such as Internet Explorer 
3
Basics of Internet
or Firefox, to access Web documents called Web pages that are linked to each other via 
hyperlinks. Web documents also contain graphics, sounds, text and video.
1.3 Search engines
Search engines are the programs which are needed to extract the information from the 
internet. They play a very important role in our daily routine, as today for each and every 
information we are dependent on internet. 
Web search engines work with the help of two programs, Spider which fetches as many 
documents as possible. Another program, called an indexer, reads the documents and 
creates an index based on the words contained in each document. Each search engine uses 
an algorithm to create its indices such that, only related results for specified keywords is 
stored and returns a list of the documents where the keywords were found. 
A search engine works in the following order:
 1. Web crawling: Web search engines work by storing information about many web 
pages. These pages are retrieved by the program known as Web crawler - which 
follows every link on the site. Web crawler may also be called a Web spider. 
 2. Indexing: Indexing also known as web indexing, it stores data to facilitate fast and 
accurate information retrieval. 
 3. Searching: A web search query fetches the result from the web search engine entered 
by the user to meet his information needs. 
Few search engines available are as follows:
2. Web ServerS
2.1 What is a Server?
A server is a computer that provides data to other computers. Th e entire structure of the 
Internet is based upon a client-server model. 
Web server helps to deliver web content that can be accessed through the Internet. The 
most common use of web servers is to host websites, as the internet is not only used to 
4
Information and Computer Technology
fetch the information but there are other uses such as gaming, data storage or running 
business applications.
The primary job of a web server is to deliver web pages to clients. The communication 
between the client node and server node takes place using the Hypertext Transfer Protocol 
(HTTP). The delivered web pages include images, style sheets and scripts in addition to 
text content. 
2.2 Server Software
A web server commonly known as HTTP server or application server is a program 
that serves content using the HTTP protocol. This content is generally in the form of 
HTML documents, images, and other web resources, but can include any type of file. The 
content served by the web server can be pre-existing (static content) or generated on the 
fly (dynamic content).
 1. Apache web server - the HTTP web server: Apache Software 
Foundation developed the free and open source web server and can be 
installed and made to work on almost all operating systems including 
Linux, Unix, Windows, FreeBSD, Mac OS X and more. Almost, 60% 
of the web server machines run the Apache web server 
 2. Apache Tomcat: Apache Tomcat  is free and open source web server 
that can run on different operating systems like Linux, Unix, Windows, 
Mac OS X, Free BSD. It was developed to support servlets and JSP 
scripts. It can serve as a standalone server. 
Page 5


1
Chapter 1
Basics of Internet
Learning Objectives 
By the end of this chapter, learner will be able to:
• 	 De fine	 the	 In t erne t.
• 	 Lis t	 the	 f ea tur es	 of	 WWW .	
• 	 Diff er en tia t e	 be tw een	 the	 In t erne t	 and	 WWW .
• 	 Under s t and	 the	 w orking	 of	 Sear ch	 Engines.
• 	 Lis t	 diff er en t	 types	 of	 ser v er s	 with	 their	 purpose.	
• 	 Under s t and	 the	 diff er en t	 c omponen ts	 of	 a	 W eb sit e.
• 	 Appr ecia t e	 the	 use	 of	 diff er en t	 pr ot oc ols.
• 	 St a t e	 the	 adv an t ag es	 &	 disadv an t ag es	 of	 cr ea ting	 Blog ging.
IntroduCtIon
Today we live in a world of technology, where internet spins a web of interconnectivity 
around the globe. Through internet more than fifty million people in countries around 
the world have been connected. Internet was evolved in 1969, under the project named 
ARPANET(Advanced Research Projects Agency Network) to connect computers at different 
universities and U.S. defence. Soon after the people from different backgrounds such as 
engineers, scientists, students and researchers started using the network for exchanging 
information and messages. 
In 1990s the internetworking of ARPANET, 
NSFnet and other private networks resulted into 
Internet. Therefore, Internet is a ‘global network 
of computer networks’ . It comprises of millions 
of computing devices that carry and transfer 
volumes of information from one device to the 
other. Desktop computers, mainframes, GPS units, 
cell phones, car alarms, video game consoles, are 
connected to the Net. 
2
Information and Computer Technology
1. World WIde Web
1.1 History of World Wide Web
The World Wide Web was invented by Tim Berners-Lee in 1989, in 1995 the first connection 
was established over what is today known as the Internet. 
By the end of 1990, the first Web page was served. In April 1993, the World Wide Web 
technology was available for anyone to use on a royalty-free basis.
Since that time, the Web has changed the world. It has perhaps become the most powerful 
communication medium the world has ever known. 
A global Web of computers known as the Internet, allows individuals to communicate 
with each other often called the World Wide Web. The Internet provides a quick and easy 
exchange of information and is recognized as the central tool in this Information Age. 
1.2 definition
The World Wide Web (WWW) is an internet based service, which uses common set of rules 
known as Protocols, to distribute documents across the Internet in a standard way. 
The World Wide Web, or ‘Web’ is a part of the Internet. The Web is viewed through web 
browser softwares such as Google Chrome, Internet Explorer, Mozilla Firefox etc. Using 
browsers one can access the digital libraries containing innumerable articles, journals, 
e-books, news, tutorials stored in the form of web pages on computers around the world 
called Web Servers. Today thousands of web pages/websites are added to the WWW every 
hour.
1.2 difference between Internet and WWW
The Internet is known as “interconnection of computer networks” . The Internet is a massive 
network of networks. It connects millions of computers together globally, forming a network 
in which any computer can communicate with any other computer as long as they are 
both connected to the Internet. Information that travels over the Internet does so via a 
variety of languages known as protocols.
The World Wide Web, or “Web” for short, or simply Web, is a massive collection of digital 
pages to access information over the Internet. 
The Web uses the HTTP protocol, to transmit data and allows applications to communicate 
in order to exchange business logic. The Web also uses browsers, such as Internet Explorer 
3
Basics of Internet
or Firefox, to access Web documents called Web pages that are linked to each other via 
hyperlinks. Web documents also contain graphics, sounds, text and video.
1.3 Search engines
Search engines are the programs which are needed to extract the information from the 
internet. They play a very important role in our daily routine, as today for each and every 
information we are dependent on internet. 
Web search engines work with the help of two programs, Spider which fetches as many 
documents as possible. Another program, called an indexer, reads the documents and 
creates an index based on the words contained in each document. Each search engine uses 
an algorithm to create its indices such that, only related results for specified keywords is 
stored and returns a list of the documents where the keywords were found. 
A search engine works in the following order:
 1. Web crawling: Web search engines work by storing information about many web 
pages. These pages are retrieved by the program known as Web crawler - which 
follows every link on the site. Web crawler may also be called a Web spider. 
 2. Indexing: Indexing also known as web indexing, it stores data to facilitate fast and 
accurate information retrieval. 
 3. Searching: A web search query fetches the result from the web search engine entered 
by the user to meet his information needs. 
Few search engines available are as follows:
2. Web ServerS
2.1 What is a Server?
A server is a computer that provides data to other computers. Th e entire structure of the 
Internet is based upon a client-server model. 
Web server helps to deliver web content that can be accessed through the Internet. The 
most common use of web servers is to host websites, as the internet is not only used to 
4
Information and Computer Technology
fetch the information but there are other uses such as gaming, data storage or running 
business applications.
The primary job of a web server is to deliver web pages to clients. The communication 
between the client node and server node takes place using the Hypertext Transfer Protocol 
(HTTP). The delivered web pages include images, style sheets and scripts in addition to 
text content. 
2.2 Server Software
A web server commonly known as HTTP server or application server is a program 
that serves content using the HTTP protocol. This content is generally in the form of 
HTML documents, images, and other web resources, but can include any type of file. The 
content served by the web server can be pre-existing (static content) or generated on the 
fly (dynamic content).
 1. Apache web server - the HTTP web server: Apache Software 
Foundation developed the free and open source web server and can be 
installed and made to work on almost all operating systems including 
Linux, Unix, Windows, FreeBSD, Mac OS X and more. Almost, 60% 
of the web server machines run the Apache web server 
 2. Apache Tomcat: Apache Tomcat  is free and open source web server 
that can run on different operating systems like Linux, Unix, Windows, 
Mac OS X, Free BSD. It was developed to support servlets and JSP 
scripts. It can serve as a standalone server. 
5
Basics of Internet
 3. Lighttpd: Lighttpd  is a free web server distributed with the FreeBSD 
operating system. This open source web server is fast, secure and 
consumes much less CPU power. Lighttpd can also run on Windows, 
Mac OS X, Linux and Solaris operating systems.
 4. Jigsaw: Jigsaw (W3C’s Server) is introduced by the World Wide 
Web Consortium. It is open source and free and can run on various 
platforms like Linux, Unix, Windows, Mac OS X Free BSD etc. Jigsaw 
is written in Java thus can run CGI scripts and PHP programs.
2.3 Services Provided by the Servers
Today many services are being provided by the Web Server. Many of the servers are based on 
Cloud computing which is popular amongst the researchers, scientists & entrepreneurs. 
Cloud Computing is distributed computing over a network, and has the ability to run a 
program or application on many connected computers at the same time.
It is used, where various computing concepts that involve a large number of computers 
are connected via real-time communication network such as the Internet. 
Various services provided by the Web server are:
 1. Cost Efficient: Web server is the most cost efficient method to use, maintain and 
upgrade. Traditional desktop software costs companies a lot in terms of finance. On 
the other hand, it is available at much cheaper rates. Besides, there are many one-
time-payment, pay-as-you-go and other scalable options available, which makes it 
very reasonable for the company.
 2. Resource Sharing: Web Server has the capability to store unlimited information such 
as Google Drives, Cloud computing etc. The space where the data can be stored is 
shared by the other users at the same time like hard disk can be shared on physical 
network as LAN. 
 3. Data Sharing: With the help of web servers one can easily access the information 
from anywhere, where there is an Internet connection using Google docs such as 
Documents, Excel sheets, Drawings, Powerpoint presentations etc.
 4. Backup and Recovery: As all the data now a days is stored on web servers, backing 
it up and restoring the same is relatively much easier than storing the same on a 
physical device. Hence, the entire process of backup and recovery much simpler than 
other traditional methods of data storage.