CLASS III:
INTRODUCTION TO INTERNET
Computers are the wonder of this century. Everywhere you look around, you will
find a computer working or someone using computer with some purpose like entertainment,
business, job or for learning.
Actually, almost every area of life is covered by computers.
People from different fields use computers differently, as you may already know.
A doctor uses computer to help his patients, and an engineer uses computers in
constructing designs and a teacher uses computer to teach his students better.
As a machine, a computer has a limited capacity. For example, like a person who
knows mathematics but not English.
But if another person who knows mathematics is ready to share, then they can share
information and benefit from each other.
If a computer can be made to share information, then automatically its capacity to
perform improves.
What is sharing? When information is shared, what are the benefits?
In computing, a shared resource, or network share, is a computer resource made
available from one host to other hosts on a computer network.
It is a device or piece of information on a computer that can be remotely accessed
from another computer, transparently as if it were a resource in the local machine. Network
sharing is made possible by communication over the network
Suppose one computer A is loaded with a movie, and another computer B with some
songs. Now, to see the movie, we must use A. Music listening is possible by using B.
Now, if we can connect both the computers, we can see movie in either A or B
computer.
We can also listen to music in either A or B computer.
Now, imagine so many computers, as if you start counting them, it may take
months, imagine that many computers.
When all that many computers are connected together, just think, how big that set
of computers will be.
These many computers are connected together in Internet to share information.
In order to send or receive information; information like photos, music, letters and
other data, these computers must remain connected in a specific manner.
You have undoubtedly heard the “the whole is greater than the sum of its parts”.
This phrase describes networking very well, and explains why it has become so popular.
A network isn't just a bunch of computers with wires running between them.
Properly implemented, a network is a system that provides its users with unique capabilities,
above and beyond what the individual machines and their software applications can provide.
Just think, if you write a letter to your friend in Vijayawada and in address, you
wrote Hyderabad, will it reach your friend?
Certainly not.
In the same manner, if there is no standard method that can direct connections
between computers, computers simply cannot do anything.
Key Concept: At a high level, networks are advantageous because they allow
computers and people to be connected together, so they can share resources.
Some of the specific benefits of networking include communication, data
sharing, Internet access, data security and management, application
performance enhancement, and entertainment.
HISTORY OF INTERNET
1960s-1970s: ARPANET:
Commonly thought of as the predecessor to the Internet and created by the US Department
of Defenses Advanced Research Projects Agency (ARPA).
This is the first network that came into existence with the concept of networking, i.e.
connecting computers with the idea of exchanging information.
The first known fully operational packet-switching network, the ARPANET was
designed to facilitate communication between ARPA computer terminals during the early
1960s, at a time when computers where far too expensive for widespread usage.
Still, it remained operational and was
very useful for many kinds of exchange of data
as well as for sending and receiving
information. Thus, in a short time, this
particular method of sharing information
became very famous.
Computers were added quickly to the
ARPANET during the following years, and work
proceeded on completing a functionally
complete Host-to-Host protocol and other
network software.
The Internet was designed to provide a communications network that would work
even if some of the major sites were down. If the most direct route was not
available, routers would direct traffic around the network via alternate routes.
The early Internet was used by computer experts, engineers, scientists, and
librarians. There was nothing friendly about it.
There were no home or office personal computers in those days, and anyone who
used it, whether a computer professional or an engineer or scientist or librarian, had to learn
to use a very complex system.
HOW IT WORKS?
Internet is based on the concept that the Internet was designed to provide a
communications network that would work even if some of the major sites were down. If the
most direct route was not available, routers would direct traffic around the network via
alternate routes.
The above thing means that in Internet, a vast number of computers are present and
connected. It also means that there are many ways to connect them.
In the process of sending
information, your computer is called
HOST – as it is sending information to
other computers.
The computer that requested
data from you and that which is receiving
information from you is CLIENT - as this
will be the place where information is
sent.
When you are receiving information, then you are called CLIENT as you are receiving
information. Then the sending computer becomes HOST- the one who actually has the
information you requested.
Now, in order to connect, many devices are used. Many computers do the work of
middlemen. They receive request from CLIENT and forward it to HOST. This process takes
places continuously at many points and the path is generally a short one. These LINKS helps
the sending and receiving of information. They work for both CLIENT and HOST.
WHY INTERNET IS IMPORTANT?
Someone once said, “if you have one book and if I have one book and if we
exchange them, both of us will have only one-one book. But if you have an idea and if I have
an idea and if we exchange them, both of us have two-two ideas.”
This same concept was the basis of Internet. By exchange of information many
things can be easily done.
A letter posted from India to England takes a week to reach. But a message sent
through Internet appears at the other end immediately.
Not only that, videos, music and many others can be easily exchanged by Internet.
Business can be easily carried out from long distances.
Like-minded people can share things through Internet. Educational training and
help is possible through internet. In fact, if we start counting the benefits of Internet, we
end up taking days.
LAB ACTIVITIES
1. OPEN INTERNET AND UNDERSTAND HOW TO VISIT A WEB SITE.
2. OBSERVE AND UNDERSTAND DIFFERENT PARTS OF A WEB SITE.
3. WHY INTERNET IS IMPORTANT?
4. WHEN YOU OPEN INTERNET, ARE YOU USING “CLIENT” OR “HOST”? EXPLAIN