What is the Internet.doc

8/14/2019 What is the Internet.doc

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What is the Internet?

A computer network is the interconnection of many individual computers, much as a road is thelink between the homes and the buildings of a city. Having many separate computers linked on a

network provides many advantages to organizations such as businesses and universities. People

may quickly and easily share files; modify databases; send messages; run programs on remotemainframes; and get access to information in databases that are too massive to fit on a small

computers hard drive. !etworks provide an essential tool for the routing, managing, and storing

of huge amounts of rapidly changing data.

"he #nternet is a network of networks$ the international linking of tens of thousands of

businesses, universities, and research organizations with millions of individual users. #t is

sometimes also referred to as the information superhighway.

Development

%hat is now known as the #nternet was originally formed in &'() as a military network calledA*PAnet +Advanced *esearch Proects Agency network- as part of the nited /tates

0epartment of 0efence. "he network opened to non1military users in the &'()s, whenuniversities and companies doing defence1related research were given access, and flourished in

the late &'2)s as most universities and many businesses around the world started to use the

#nternet. #n &''3, when commercial companies were first permitted to sell #nternet connectionsto individuals, usage of the network grew tremendously. "here were millions of new users within

months, and a new era of computer communications began. "oday, it is estimated that over 2))

million people use the #nternet worldwide.

Terminology

4earning about the #nternet can be a bit confusing at first, but it becomes a lot simpler if you canbecome familiar with some of the terminology used when talking about the #nternet. Here is a list

of common words and phrases that you might hear.

&- 5n1line

6ou may sometimes hear people talk about 7being on1line8. "his is ust another way of

saying that they are using the #nternet.

9- %%%

"his stands for the World1Wide1Web. "im :erners14ee, a physicist in /witzerland,

invented the %orld %ide %eb in &''9 as a way to organize and access information onthe #nternet. #ts introduction caused the popularity of the #nternet to eplode nearly

overnight. #nstead of only being able to download simple linear tet, with the

introduction of the %orld %ide %eb users could download web pages that contain tet,graphics, and even animations, video, and sound.

3- %eb browser


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A web browser is a program that runs on users computers and allows them to view and

interact with the web pages on the %orld %ide %eb. "he most common web browsers

are calledInternet ExplorerandNetscape.

surf the web>when they ump from one page to another in search of information.

?- %eb site

@any commercial companies maintain web sites, or sets of web pages, that theircustomers can view. "he companies can engage in e1commerce, or electronic commerce,

by describing their products on their web sites. ustomers who view the web pages can

read the descriptions and then purchase products directly from the companies by sending

orders back over the #nternet. :uying and selling stocks and other investments is anotherpopular web activity.

@any organizations and educational institutions also have web sites. "hey use their sites

to promote themselves and their causes, to disseminate information, and to solicit funds

and new members. Bven many private individuals now have their own web sites. "heycan fill their pages with photographs and personal information for viewing by friends and

associates.

C- *4"his stands for a UniformResource Locator. "o visit a %eb site, users type the *4,

which is the sites address, into the web browser. An eample of a *4 is

www.yahoo.com.

(- %eb server

A web server is a computer that stores a web site, and is responsible for servicingrequests for viewing that web site. Clientcomputers send requests for particular *4s to

the web server, which then finds the appropriate web page, and sends it back to the client

computer. A web server on the #nternet must have a permanent #nternet connection, so

that whenever a client computer requests a *4, the web server can respond straightaway.

2- #/P#/P stands for Internet Service Provider, a company whose business is to provide #nternet

connections to paying customers. "he customer uses a modem to dial the telephone

number of the #/P from their personal computer.

'- H""PDH""P/

A communications protocolis simply a set of rules that computers use to communicate

over a network. "he Hypertet Transfer Protocol +H""P- is the means by which
http://www.yahoo.com/http://www.yahoo.com/http://www.yahoo.com/


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computers on the %%% communicate. H""P/ is the secure version of H""P. H""P/ is

used on web sites where sensitive information such as bank details is echanged.

&)- H"@4

"he Hypertet Markup Language is the language used to write most web sites on the

%%%. H"@4 pages typically consist of some tet together with formatting instructionsand information about what graphics or audio clips to include in the web page.

&&- E@4"he Bxtensible Markup Language is an alternative language for writing web pages.

%hereas H"@4 pages describe the format of the dataFs presentation, pages written in

E@4 describe only how the data is structured. E@4 provides a standard format for the

movement of data in and between applications. "he data in an E@4 file usually requiressome other application to interpret the data and display it in a useful format.

&9- %3

"he World Wide Web Consortium is a group of eperts who meet regularly to developcommon protocols for the evolution of the %%%. "he %3 agrees on standards for

H"@4, E@4 and other web technologies, and for how web browsers should interpretthem.

Web evelopment tools

A number of tools eist for use by web authors+i.e. people who write web sites-.

&- H"@4DE@4As was mentioned in the previous section, H"@4 and E@4 are the two main languages

used for writing web pages. %eb authors can use a simple tet editor such as !otepad to

enter the H"@4DE@4 commands. "he final page can then be viewed using a webbrowser.

9- %eb scripting%eb scripting is a way of creating dynamic web content. "his means that the content of

the web page will not be the same every time you look at it G it will change dynamically

depending on certain factors such as the actions of the person viewing the page. "his

enables web authors to create web sites that people can interact with by entering tet orclicking on different buttons.

0ynamic web content creation is made possible by running a small program called ascript. "here are two types of web scripting$ client-side scripting and server-side

scripting. #n client1side scripting the script is run on the clientmachine +i.e. the computer

requesting the web page-, and in server1side scripting the script is run on the web server+i.e. the computer that responds to the request-.

"here are two main techniques for web1scripting$ the ommon ateway #nterface +#-,


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which does server1side scripting only, and Active /erver Pages +A/P-, which can be used

for both client and server1side scripting.

3- Iava

Another way of creating dynamic web content is to use the Javaprogramming language.

Iava is an obect1oriented language that was designed specifically with the #nternet inmind. Iava offers two ways of creating dynamic web content$ applets, which are Iava

programs which are run by a client computerFs web browser, and servlets, which are Iava

programs which are run by the web server.

Documents

What is the Internet.doc