Bird View of Internet

8/14/2019 Bird View of Internet

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What is InternetWhat is Internet

Internet is an Inter-connection amongInternet is an Inter-connection among

several computers of different typesseveral computers of different types

belonging to various networks all overbelonging to various networks all over

the globe.the globe. It is often described as It is often described as network ofnetwork of

networksnetworks because all the smaller because all the smaller

networks of organisations are linkednetworks of organisations are linkedtogether into one giant network.together into one giant network.


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Internet is a world wide organisationInternet is a world wide organisation

of computer network. When you areof computer network. When you are

at Internet, you become a part ofat Internet, you become a part of

that group of millions of people whothat group of millions of people whouse the computer for exchanginguse the computer for exchanging

their idea and information.their idea and information.

Internet is also referred as web.Internet is also referred as web.


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Internet is Information SuperInternet is Information Super

HighwayHighway

Internet is called the Highway ofInternet is called the Highway of

information. When you travel on ainformation. When you travel on ahighway, you come across differenthighway, you come across different

people, incidents and groups,people, incidents and groups,

likewise Internet is also a treasure orlikewise Internet is also a treasure or

source of information.source of information.


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History of InternetHistory of Internet

19691969 is the birth year of Internetis the birth year of Internet

ARPAnetARPAnet (Advanced Research(Advanced Research

Projects Agency Network) was theProjects Agency Network) was the

first network started by Departmentfirst network started by Department

of Defence (DOD) of United States ofof Defence (DOD) of United States of

America.America.

It began in with one computer atIt began in with one computer at

California and three at Utah.California and three at Utah.


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Later to share the software andLater to share the software and

hardware resources, the militaryhardware resources, the militaryallowed Universities to join theallowed Universities to join the

network and gradually by the yearnetwork and gradually by the year

1979, it started being known as1979, it started being known as

Internet.Internet.


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The OSI ModelThe OSI Model

->->Open system Interconnection (OSI)Open system Interconnection (OSI)

was developed by ISO (Internationalwas developed by ISO (International

Standards Organization)Standards Organization)

->->OSI that follows a set of protocols thatOSI that follows a set of protocols thatallows any two different systems toallows any two different systems to

communicate with each other regardless ofcommunicate with each other regardless of

their underlying architecture.their underlying architecture.


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ContinContin

The OSI model is a layered frameworkThe OSI model is a layered framework

for the designing of network systemsfor the designing of network systems

that allows communication between allthat allows communication between all

types of computer systems.types of computer systems.

It consists of seven separate but relatedIt consists of seven separate but related

layers, each of which defines a part oflayers, each of which defines a part of

the process of moving informationthe process of moving informationacross a network.across a network.


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Session

Physical

Transport

NetworkData Link

Presentation

Application

What are the seven layers ?What are the seven layers ?

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3Layer 2

Layer 1


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LayersLayers

In the sense of purpose and responsibility, each layer isIn the sense of purpose and responsibility, each layer isseparate and independentseparate and independent

Each has its own function, but also provides a service toEach has its own function, but also provides a service tothose layers above and below itselfthose layers above and below itself

The model should be considered an aid to understandingThe model should be considered an aid to understandingthe nature of communication on the networkthe nature of communication on the network and usefuland usefulin sorting out troubles that might occur on a networkin sorting out troubles that might occur on a network

By providing, it allows both software engineers andBy providing, it allows both software engineers andhardware manufacturers ensure their products workhardware manufacturers ensure their products worktogether.together.


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The layers at workThe layers at work

Supports the communication between

applications over the network

Presents data to the receiver

in a form it recognises

Establishes a connection and

terminates it when no longer required

Acknowledges the flow of data

including re-transmission where required

Adds the appropriate networkaddresses to packets

Adds the MAC addresses to packets

Transmits the data on the medium

NODE A

Sending Device

NODE B

Receiving Devic e

Layer 7

Application Layer

Layer 6

Presentation Layer

Layer 5

Session Layer

Layer 4

Transport Layer

Layer 3Network Layer

Layer 2

Data Link Layer

Layer 1

Physical Layer

Layer 7

Application Layer

Layer 6

Presentation Layer

Layer 5

Session Layer

Layer 4

Transport Layer

Layer 3Network Layer

Layer 2

Data Link Layer

Layer 1

Physical Layer


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How does data flow 1 ?How does data flow 1 ?

When data is sent from the application onWhen data is sent from the application onthe source computer the followingthe source computer the followinghappenshappens

Data in the form of aData in the form of apacketpacketmoves downmoves downthrough the layersthrough the layers When it reaches the Physical Layer it isWhen it reaches the Physical Layer it is

ready to be sent along the cableready to be sent along the cable

At the Physical Layer the bits may beAt the Physical Layer the bits may beanalogueanalogue oror digitaldigital, in the form of, in the form ofelectricalelectrical,, lightlightoror radio wavesradio waves


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How does data flow ? (2)How does data flow ? (2)

The data is transmitted to the destinationThe data is transmitted to the destinationdevicedevice

It travels up through the layers of the OSIIt travels up through the layers of the OSImodel, reaching the user.model, reaching the user.

As data moves down through the layers it isAs data moves down through the layers it is

encapsulatedencapsulated

ie additional information isie additional information isadded.added. The data in the packet doesThe data in the packet does notnot changechange


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Customer

Customer

Customer

Customer

Customer

Internet Cloud

CustomerCustomer

Customer

Customer

Web serverWeb server



Web serverWeb serverWeb serverWeb server


How does internetHow does internet

work?work?


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Internet uses a protocol calledInternet uses a protocol called TCP\IPTCP\IP

Each system is assigned with anEach system is assigned with an IP addressIP address

Each server has a name calledEach server has a name called Domain NameDomain NameWe refer to the server with Domain NameWe refer to the server with Domain Name

AA DNSDNS (Domain Naming Service) Server resolves(Domain Naming Service) Server resolves

the IP address with the namethe IP address with the name


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Internet

Cloud

Customer



ISPISP

RouterRouter


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What do we need to connectWhat do we need to connect

InternetInternet

A ComputerA Computer

A ModemA Modem

Connecting MediaConnecting Media

Account with ISPAccount with ISP

Web BrowserWeb Browser


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ComputerComputer

A Computer is the basic requirementA Computer is the basic requirement

to access Internet.to access Internet.


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ModemModem

Modem is the modulator andModem is the modulator and

demodulator which converts analogdemodulator which converts analog

to digital signal and vice-versa.to digital signal and vice-versa.

It can be internal or external.It can be internal or external.


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Connecting MediaConnecting Media

Connecting Media can beConnecting Media can be

Ordinary Telephone lineOrdinary Telephone line

ISDN lineISDN line Leased lineLeased line

Cable connectionCable connection


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ISP (Internet Service Provider)ISP (Internet Service Provider)

ISPs are those who connect theISPs are those who connect the

individual users to the Internet. Theyindividual users to the Internet. Theysetup a server which are connectedsetup a server which are connected

to the Internet through dedicatedto the Internet through dedicated

lines round the clock.lines round the clock.


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Some common ISPsSome common ISPs

America OnlineAmerica Online

India OnlineIndia Online

Satyam OnlineSatyam Online VSNLVSNL

SeraphicSeraphic

Sky CableSky Cable


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Web BrowserWeb Browser

It is a software and necessary tool forIt is a software and necessary tool for

exploring the web. It helps to moveexploring the web. It helps to movefrom one web site to another webfrom one web site to another web

site.site.


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Some popular web browsers areSome popular web browsers are

MosaicMosaic

Neo PlanetNeo Planet

Netscape NavigatorNetscape Navigator

OperaOpera

Internet ExplorerInternet Explorer


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How to access InternetHow to access Internet

The user has to register himself toThe user has to register himself to

any one of the ISPs by paying theany one of the ISPs by paying the

requisite amount.requisite amount. Different ISPs have different tariffsDifferent ISPs have different tariffs

and different ways of registrations.and different ways of registrations.


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Why do we use InternetWhy do we use Internet

To get in touch with near and dearsTo get in touch with near and dears

throughthroughElectronic mail (E-mail)Electronic mail (E-mail)

Keyboard chatKeyboard chat

Internet TelephoneInternet Telephone

Video ConferencingVideo Conferencing


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Continue..Continue..

To access to lots of databases,To access to lots of databases,

libraries and news groups around thelibraries and news groups around the

world for gaining information on anyworld for gaining information on any

topics of your interest.topics of your interest. To access and share information onTo access and share information on

all topics ranging from agriculture toall topics ranging from agriculture to

astronomy.astronomy.


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ContCont

To stay up-to-date with news, sports,To stay up-to-date with news, sports,

weather & world wide current affairs.weather & world wide current affairs.

To listen sounds, music and watchTo listen sounds, music and watch

digital movies.digital movies.

To enjoy a number of interactiveTo enjoy a number of interactive

multimedia games and gain knowledgemultimedia games and gain knowledge

through several educational tools.through several educational tools. To visit an electronic zoo or aTo visit an electronic zoo or a

museum.museum.


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ContinueContinue

To get latest information aboutTo get latest information about

movies & your favorite stars.movies & your favorite stars.

You can also publish informationYou can also publish informationabout yourself, your family, yourabout yourself, your family, your

organisation, hobbies and interests.organisation, hobbies and interests.

To learn foreign language & to makeTo learn foreign language & to makefriends globally.friends globally.

And there is no limit to it.And there is no limit to it.


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Electronic MailElectronic Mail(The Internet as a post man)(The Internet as a post man)

Electronic mail or e-mail is theElectronic mail or e-mail is the

process of sending and receiving ofprocess of sending and receiving ofmessages by one user to one ormessages by one user to one or

more other computer users over amore other computer users over a

computer network in a digital form.computer network in a digital form.


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By using email, you will be able to electronicallyBy using email, you will be able to electronically

Send messages or memosSend messages or memos

Receive and read messagesReceive and read messages Reply to messagesReply to messages

Forward messagesForward messages


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Send the same message to a list ofSend the same message to a list of

people with one strokepeople with one stroke

Attach a text file such as a report toAttach a text file such as a report to

your email messageyour email message

Save mail to a file and print theSave mail to a file and print the

messagemessage


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How does it workHow does it work

The process of e-mail is also very similarThe process of e-mail is also very similar

to traditional mail.to traditional mail.

An e-mail is made up of two parts, theAn e-mail is made up of two parts, the

address and the message. Depending onaddress and the message. Depending onthe address, the message is sent to thethe address, the message is sent to the

receiver of the letter. But the message isreceiver of the letter. But the message is

not delivered. Instead, it is stored in thenot delivered. Instead, it is stored in the

mail server. When the receiver logs in andmail server. When the receiver logs in andchecks In-box, he gets his message.checks In-box, he gets his message.


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E-mail AccountE-mail Account

To become an e-mail user, you need toTo become an e-mail user, you need to

setup your own email-account.setup your own email-account.

There are number of sites with whomThere are number of sites with whomyou can register your e-mail account.you can register your e-mail account.

They also provide additional servicesThey also provide additional services

such as receiving regular news fromsuch as receiving regular news from

various sites of your choice.various sites of your choice. Some of them are free whereas forSome of them are free whereas for

others, you have to payothers, you have to pay


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Some of the sites to provide free e-Some of the sites to provide free e-

mail services aremail services are

www.yahoo.comwww.yahoo.com

www.hotmail.comwww.hotmail.com

www.rediff.comwww.rediff.com
http://www.yahoo.com/http://www.yahoo.com/http://www.hotmail.com/http://www.hotmail.com/http://www.rediff.com/http://www.rediff.com/http://www.rediff.com/http://www.hotmail.com/http://www.yahoo.com/


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Some of the sites to provide paid e-Some of the sites to provide paid e-

mail service aremail service are

www.123india.comwww.123india.com

www.usa.netwww.usa.net

www.mahaemail.comwww.mahaemail.com
http://www.123india.com/http://www.123india.com/http://www.usa.net/http://www.usa.net/http://www.mahaemail.com/http://www.mahaemail.com/http://www.mahaemail.com/http://www.usa.net/http://www.123india.com/


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Setting of e-mail accountSetting of e-mail account

Click atClick at New User?New User? Sign upSign up


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E-mail AddressE-mail Address

In order to receive or send email,In order to receive or send email,

you need to have an email addressyou need to have an email address

and you need to know the address ofand you need to know the address of

the person to whom you wish tothe person to whom you wish to

send a message.send a message.


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Addresses are made up in aAddresses are made up in astandard way using the followingstandard way using the following

elements:elements:

User identification e.g.User identification e.g. egtogetegtoget,,your name or a name you wish toyour name or a name you wish to

choose. It is usual to have part ofchoose. It is usual to have part of

your own name to make it easilyyour own name to make it easily

identifiable.identifiable.

TheThe @@or at symbol to separateor at symbol to separate

user name and domain nameuser name and domain name


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The domain name of the computerThe domain name of the computer

receiving your mail e.g.receiving your mail e.g. yahooyahoo forfor

Yahoo.comYahoo.com The type of organisation e.g.The type of organisation e.g. coco

for commercial organisation orfor commercial organisation or

govgov for government.for government. And finallyAnd finally inin to locate the addressto locate the address

in Indiain India


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The final address will look like this:The final address will look like this:

[email protected]@yahoo.com


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How to send e-mailHow to send e-mail

Email messages are generally sentEmail messages are generally sent

from and received by mail servers-from and received by mail servers-

computers that are dedicated forcomputers that are dedicated for

processing & directing e-mail. Once aprocessing & directing e-mail. Once aserver has received a message, itserver has received a message, it

directs it to the specific computer todirects it to the specific computer to

which the e-mail is addressedwhich the e-mail is addressed


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Advantages of E-mailAdvantages of E-mail

Speed: It is a fast means ofSpeed: It is a fast means of

communicationcommunication

Multimedia: Along with text, sound,Multimedia: Along with text, sound,images, video and computerimages, video and computer

software can be sent.software can be sent.

Cost: It is lot cheaper than postalCost: It is lot cheaper than postalmail.mail.


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Disadvantages of E-mailDisadvantages of E-mail

You cant send anything without anYou cant send anything without an

e-mail facilitye-mail facility You cant send anything physical likeYou cant send anything physical like

money, book or floppy.money, book or floppy.


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ChattingChatting

Chatting is one of the most popularChatting is one of the most popular

activities on the Internet andactivities on the Internet and

involves people of all ages cominginvolves people of all ages coming

together in areas where they can jointogether in areas where they can joinin on in a variety of topics that theyin on in a variety of topics that they

are interested in with people allare interested in with people all

around the world.around the world.


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One of the most popular forms ofOne of the most popular forms of

online chatting is Web-basedonline chatting is Web-based

chats. Web-based chats are,chats. Web-based chats are,

essentially, specially designed Webessentially, specially designed Websites that allow visitors tosites that allow visitors to

exchange messages with oneexchange messages with one

another in real-time.another in real-time.


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When you visit a Web-based chat site forWhen you visit a Web-based chat site forthe first time, you will be asked tothe first time, you will be asked tochoose a name (or 'alias') and achoose a name (or 'alias') and a

password. You can choose any namepassword. You can choose any nameyou like and that is the name by whichyou like and that is the name by whichyou will be known to all otheryou will be known to all otherparticipants on that particular site.participants on that particular site.

The password is used to confirm yourThe password is used to confirm youridentity each time you visit the siteidentity each time you visit the site(only you should know the password(only you should know the passwordthat you selected when you signed up).that you selected when you signed up).


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The best feature of Web-based chats is thatThe best feature of Web-based chats is that

you access them with your Web browseryou access them with your Web browserno special software is required.no special software is required.


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When youll click on any chatWhen youll click on any chat

category, the next screen will displaycategory, the next screen will display

the chat rooms i.e. the chat areas.the chat rooms i.e. the chat areas.


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Chat rooms can have specific orChat rooms can have specific orbroad themes. One chat room mightbroad themes. One chat room mightbe dedicated to teenagers. Anotherbe dedicated to teenagers. Another

might be dedicated to sports buffs ormight be dedicated to sports buffs orcartoon fanatics. The chat roomscartoon fanatics. The chat roomsthemselves will be clearly labeled,themselves will be clearly labeled,and you will be provided withand you will be provided with

instructions on how to accessinstructions on how to accessparticular chat rooms on the siteparticular chat rooms on the siteitself.itself.


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Chat rooms generally include a text boxChat rooms generally include a text box

for typing your messages, a large windowfor typing your messages, a large windowarea used to display the messages typedarea used to display the messages typedby chat participants and a smaller windowby chat participants and a smaller window

with a list of all the participants in the chatwith a list of all the participants in the chatroom.room.


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To help you keep track of who is saying what,To help you keep track of who is saying what,each message is preceded by the name of theeach message is preceded by the name of theperson that sent it. Also, on some chat systems,person that sent it. Also, on some chat systems,messages are displayed in different colours.messages are displayed in different colours.

As a general rule, your messages are broadcastAs a general rule, your messages are broadcastto the screens of all the other chat participantsto the screens of all the other chat participantsas soon as you elect to send it (usually byas soon as you elect to send it (usually byclicking the 'send' icon or hitting the Return/Enterclicking the 'send' icon or hitting the Return/Enter

key).key).


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Some of the more advancedSome of the more advancedWeb-based chats allow you toWeb-based chats allow you tohold private conversations, sohold private conversations, so

that your messages only appearthat your messages only appearon the screens of thoseon the screens of thoseparticipants that you wish to talkparticipants that you wish to talk

to.to.


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The Web isn't the only place where youThe Web isn't the only place where you

can meet people online.can meet people online.

Instant messaging is becoming anInstant messaging is becoming an

increasingly popular means ofincreasingly popular means of

communicating one-to-one with friends.communicating one-to-one with friends.

Instant MessagingInstant Messaging


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Web-based chats are generally'public' forums, so everyone can

read your messages.

Instant messaging largelyovercomes these problems, but totake advantage of instantmessaging features, users must firstdownload and install special

software.


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Each time you connect to the Internet and

run your instant messaging software, a list

of all your friends currently online isdisplayed. You can then compose and

send messages to your friends. The

messages will be displayed immediately on

their computer screens. Alternatively, theirinstant messaging software will 'beep' to

alert them of an incoming message.


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Instant messaging softwareInstant messaging software

Some of the instant messagingSome of the instant messaging

software are:software are:

ICQ-http://www.icq.com/ICQ-http://www.icq.com/Ichat-http://www.ichat.comIchat-http://www.ichat.com

Yahoo! Messenger-Yahoo! Messenger-

http://messenger.yahoo.com/http://messenger.yahoo.com/PowWow-http://www.tribal.com/powwow/PowWow-http://www.tribal.com/powwow/


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What is video conferencingWhat is video conferencing

If you would like to be a receiver that isIf you would like to be a receiver that isonly see and hear the conversation, youonly see and hear the conversation, you

will be able to do this any standard Macwill be able to do this any standard Mac

and if you have a Sound card and Videoand if you have a Sound card and Videocard on any standard PC.card on any standard PC.

If you would also like to be a sender thatIf you would also like to be a sender that

is-transmit your voice and video, you willis-transmit your voice and video, you will

also need a digital camera and PC usersalso need a digital camera and PC userswill need a microphone.will need a microphone.


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How to download filesHow to download files

Downloading refers to the actualDownloading refers to the actual

transferring of the document from thetransferring of the document from the

internet to your own computer.internet to your own computer.

Setting up a separate downloadSetting up a separate download

directory to store your downloaded filesdirectory to store your downloaded files

into it so that they dont get mixed upinto it so that they dont get mixed up

with any other programs/files on yourwith any other programs/files on yoursystem, and so you always know wheresystem, and so you always know where

you can find them should you have toyou can find them should you have to

reinstall or find the files at a later date.reinstall or find the files at a later date.


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What is search EngineWhat is search Engine

Search engines exist to help you findSearch engines exist to help you find

the relevant information you require.the relevant information you require.

With a search engine, you can sortWith a search engine, you can sortthrough vast amounts of onlinethrough vast amounts of online

information and pinpoint the materialinformation and pinpoint the material

you wantyou want


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Search engines work by matchingSearch engines work by matching

words you enter with the samewords you enter with the samewords found in various informationwords found in various information

sites on the internetsites on the internet


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Some of the famous search enginesSome of the famous search engines

areare

www.google.comwww.google.com

www.altavista.comwww.altavista.com

www.yahoo.comwww.yahoo.com

www.indiatimes.comwww.indiatimes.com

M h i
http://www.google.com/http://www.google.com/http://www.altavista.com/http://www.altavista.com/http://www.yahoo.com/http://www.yahoo.com/http://www.indiatimes.com/http://www.indiatimes.com/http://www.indiatimes.com/http://www.yahoo.com/http://www.altavista.com/http://www.google.com/


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MathematicsMathematics

Internet helps students to getInternet helps students to getinformation from a to z in mathsinformation from a to z in maths

through many free sites. Some ofthrough many free sites. Some of

them are:them are:www.plus.maths.orgwww.plus.maths.org

www.archives.math.utk.eduwww.archives.math.utk.edu

www.mathworld.wolfram.comwww.mathworld.wolfram.com

S t
http://www.plus.maths.org/http://www.plus.maths.org/http://www.archives.math.utk.edu/http://www.archives.math.utk.edu/http://www.mathworld.wolfram.com/http://www.mathworld.wolfram.com/http://www.mathworld.wolfram.com/http://www.archives.math.utk.edu/http://www.plus.maths.org/


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SportsSports

Some sites providing free informationSome sites providing free information

about sports are:about sports are:

www.espn.go.comwww.espn.go.com

www.sports.yahoo.comwww.sports.yahoo.com

www.khel.comwww.khel.com

SS i
http://www.espn.go.com/http://www.espn.go.com/http://www.sports.yahoo.com/http://www.sports.yahoo.com/http://www.khel.com/http://www.khel.com/http://www.khel.com/http://www.sports.yahoo.com/http://www.espn.go.com/


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ScienceScience

Some sites that provide freeSome sites that provide free

information related to science are:information related to science are:

www.plus1plus2.comwww.plus1plus2.comwww.sciencenews.orgwww.sciencenews.org

www.sciencedaily.comwww.sciencedaily.com

G l K l dG l K l d
http://www.plus1plus2.com/http://www.plus1plus2.com/http://www.sciencenews.org/http://www.sciencenews.org/http://www.sciencedaily.com/http://www.sciencedaily.com/http://www.sciencedaily.com/http://www.sciencenews.org/http://www.plus1plus2.com/


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General KnowledgeGeneral Knowledge

Some of the sites where you can gainSome of the sites where you can gain

knowledge:knowledge:

www.knowledgebk.comwww.knowledgebk.com

www.encarta.msn.comwww.encarta.msn.com

www.nytimes.comwww.nytimes.com

NN
http://www.knowledgebk.com/http://www.knowledgebk.com/http://www.encarta.msn.com/http://www.encarta.msn.com/http://www.nytimes.com/http://www.nytimes.com/http://www.nytimes.com/http://www.encarta.msn.com/http://www.knowledgebk.com/


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NewsNews

Various sites to get online newsVarious sites to get online news

instantly are:instantly are:

www.aajtak.comwww.aajtak.com

www.cnn.comwww.cnn.com

www.bbc.comwww.bbc.com

www.ch.comwww.ch.com

CiCi
http://www.aajtak.com/http://www.aajtak.com/http://www.cnn.com/http://www.cnn.com/http://www.bbc.com/http://www.bbc.com/http://www.bbc.com/http://www.cnn.com/http://www.aajtak.com/


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CinemasCinemas

We can view the clippings of anyWe can view the clippings of any

movie on net through these sites:movie on net through these sites:

www.indiafm.comwww.indiafm.com

www.bollywoodheaven.comwww.bollywoodheaven.com

www.amazon.comwww.amazon.com
http://www.indiafm.com/http://www.indiafm.com/http://www.bollywoodheaven.com/http://www.bollywoodheaven.com/http://www.amazon.com/http://www.amazon.com/http://www.amazon.com/http://www.bollywoodheaven.com/http://www.indiafm.com/


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Bird View of Internet