The ABC of Internet and World Wide Web

The Internet

The Internet is a global network connecting millions of computers．More than 100 countries are linked into exchanges of data，news and opinions．

Unlike online services，which are centrally controlled，the Internet is decentralized by design．Each Internet computer，called a host，is independent．Its operators can choose which Internet services to use and which local services to make available to the global Internet community．Remarkably，this anarchy by design works exceedingly well．

There are a variety of ways to access the Internet．Most online services，such as America Online，offer access to some Internet services．It is also possible to gain access through a commercial Internet Service Provider(ISP)．

The World Wide Web

The World Wide Web is a system of Internet servers that support specially formatted documents．The documents are formatted in a markup language called HTML(Hypertext Markup Language)that supports links to other documents，as well as graphics，audio，and video files．This means you can jump from one document to another simply by clicking on hot spots．Not all Internet servers are part of the World Wide Web．

There are several applications called Web browsers that make it easy to access the World Wide Web;two of the most popular being Netscape Navigator and Microsoft's Internet Explorer．

The Difference between the Internet and the World Wide Web

Many people use the terms Internet and World Wide Web(the Web)interchangeably，but in fact the two terms are not synonymous．The Internet and the Web are two separate but related things．The Internet is a massive network of networks，a networking infrastructure．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 simply Web，is a way of accessing information over the medium of the Internet．It is an information-sharing model that is built on top of the Internet．The Web uses the HTTP protocol，only one of the languages spoken over the Internet，to transmit data．Web services，which use HTTP to allow applications to communicate in order to exchange business logic，use the Web to share information．The Web also utilizes browsers，such as Internet Explorer or Netscape，to access Web documents called Web pages that are linked to each other via hyperlinks．Web documents also contain graphics，sounds，text and video．

The Web is just one of the ways that information can be disseminated over the Internet．The Internet，not the Web，is also used for e-mail，which relies on SMTP，USENET news groups，instant messaging and FTP．So the Web is just a portion of the Internet，albeit a large portion，but the two terms are not synonymous and should not be confused．

The Brief History of the Internet and the World Wide Web

In 1968，a pioneering long-haul wide area network was funded by DARPA．DARPA is an agency of the US Department of Defense responsible for the development of new technology for use by the military．The network was called ARPAnet(Advanced Research Projects Agency Network)．It then became operational and served as the basis for early networking research，as well as a central backbone during the development of the Internet．Quickly realizing the usefulness of such a network，researchers at colleges and universities soon began using it to share data．In the 1980s the military portion of the early Internet became a separate network called the MILnet．Meanwhile，the National Science Foundation(NSF)began overseeing the remaining non-military portions，which is called the NSFnet．Thousands of commercial(.com or.co)，university(.ac or.edu)and other research networks(.org，.net)began connecting to the NSFnet．

Until the advent of the World Wide Web in 1990，the Internet was almost entirely unknown outside universities and corporate research departments and was accessed mostly via command line interfaces such as Telnet and FTP．Since then it has grown to become an almost-ubiquitous aspect of modern information systems，becoming highly commercial and a widely accepted medium for all sorts of customer relations such as advertising，brand building，and online sales and services．Its original spirit of cooperation and freedom have，to a great extent，survived this explosive transformation with the result that the vast majority of information available on the Internet is free of charge．

Notes

1．network:A group of two or more computer systems linked together．

2．data:Distinct pieces of information，usually formatted in a special way．

3．host:A computer that is connected to a TCP/IP network，including the Internet．Each host has a unique IP address．

4．America Online:A popular online service．It is often abbreviated as AOL．

5．ISP:Internet Service Provider，a company that provides access to the Internet．For a monthly fee，the service provider gives the user a software package，user name，password and access phone number．Equipped with a modem，the user can then log on to the Internet and browse the World Wide Web，and send and receive e-mail．

6．hot spot:An area of a graphics object，or a section of text，that activates a function when selected．Hot spots are particularly common in multimedia applications，where selecting a hot spot can make the application display a picture，run a video，or open a new window of information．

7．Netscape Navigator:Netscape Communication's popular Web browser．There are many versions of Navigator，and it runs on all the major platforms—Windows，Macintoshes，and UNIX．

8．Microsoft's Internet Explorer:Often abbreviated as IE，Microsoft's Web browser．Like Netscape Navigator，Internet Explorer enables you to view Web pages．Both browsers support Java and JavaScript．Internet Explorer also supports ActiveX．

9．protocol:An agreed-upon format for transmitting data between two devices．

10．hyperlink:An element in an electronic document that links to another place in the same document or to an entirely different document．

11．SMTP:Short for Simple Mail Transfer Protocol，a protocol for sending e-mail messages between servers．

12．USENET:A worldwide bulletin board system that can be accessed through the Internet or through many online services．

13．instant messaging:Abbreviated IM，a type of communications service that enables you to create a kind of private chat room with another individual in order to communicate in real time over the Internet．

14．FTP:Short for File Transfer Protocol，the protocol for exchanging files over the Internet．

15．MILnet:Military Network．

16．NSFnet:National Science Foundation Network．

Questions for Further Discussion

1．How is the Internet different from the internet(with a small“i”)?

2．How can we benefit from the using of Internet?