Internet

Internet Resources

Internet

Also called

• Inter-connected network

• Internetworking

History of Internet

• 1969 Advanced Research Project Agency

Network (ARPANET) under the

Department of U. S. Defense

• Aims– maintain communication in case of a nuclear war– share information– discuss topics of interest– research various subjects

History of Internet

• 1977 TCP/IP (Transmission Control

Protocol/Internet Protocol)• 1986 NSFNET• 1991 WAIS (Wide Area Information

Servers)- Gopher

* text-base information

* in UNIX environment

History of Internet

• 1992 WWW• 1993 Mosaic

- the first WWW graphical browser

• 1994 Netscape- multi-media

information/hypermedia

information

-Windows environment

Why “on the Internet”?

• freedom– no “Internet” company– no board of directors, no bosses– no official censors

• bargain– doesn’t charge for anything

• belongs to everyone• not dependent upon proximity

Internet Resources

• Worldwide Web (WWW)

• Newsgroup(Usenet)

• Bulletin Board System (BBS)

• Electronic Mail (E_mail)

• Conversation over the Internet (Chat)

• Remote Logon (Telnet)

• File Transfer Protocol (FTP)

World Wide Web (WWW)

• also called Web, WWW or W3

• a part of the Internet

• a system that enables users to find and retrieve information by navigating through linked hypertext documents

• a huge collection of documents stored on computers around the world

Terminology : WWW

• Web Page– a document on the Web– include text, pictures, sound and video

• Web Site– a collection of Web pages– always maintained by a college, university,

government, company or individual

Characteristics of WWW

• Hypertext– text is interlaced with links that allow to read

information not only in a linear fashion but easily jump to new entry point

• Hypermedia– links point to information either be textual,

graphical, sound or movies

Characteristics of WWW• Graphical

– browsers are best at displaying graphical contents

• Cross-platform

• Global & Distributed– links point to information anywhere on the internet

• Dynamic– information is easy to update

• Interactive

3 set of rules in WWW

• HTML (Hypertext Markup Language)– ordinary text files including tags that control

the appearance of the file.– tags can also define a word or phrase as a link– users need a web browser program to view web

pages

3 set of rules in WWW

• HTTP (Hypertext Transport Protocol)– allows a networked computer to listen for and

respond to incoming requests for files

• URL (Uniform Resource Locator)– URL is the Internet address for a web document

or other file– users can retrieve documents either by

• manually entering URL

• selecting links that contains a URL

Guideline for surfing the Internet

• hands-on experience is essential

• accompany the students to find interesting user-friendly sites

• bookmark the favorite WWW sites

• consider setting limits on the amount of time per day to spend on the Internet

Guideline for surfing the Internet

• If the students do surf by themselves, check up on them once in a while

• advise your students never give out their name, address, phone number, photos to anyone on-line without first consulting the teacher/parent

• Internet is similar to the rest of the world. Use common sense as one would on the street

Basic requirement for subscription of internet services

• computer• modem• telephone line• ISP description

– utilities programs– user name, pasword, e_mail address

• Others– windows

Some common Web Browsers

• Browser is a program that let you view and explore in formation on the Web

• For example– Mosaic– Netscape Navigator– Internet Explorer

Common Search Engines

• Yahoo

• Infoseek

• Lycos

• Excite

• etc..

News/Discussion groups

• USENET is a system of discussion groups• It is free of charges• It offers bulletin boards, chat rooms and

network news• Join the group for

– reading some particular articles– discussing topics of interest– seeking for advice of certain problems

Bulletin Board System (BBS)

• an electronic bulletin board computer system provides places for posting articles, which are used to– distribute information– express opinions– seek for advice– reply to an article

Conversation over the Internet (Chat)• Using the same chat system, Conversation can

be made– between 2 persons– among a group of people– to the public

• It can communicate text messages back and forth, if microphone and sound capability are available, actual voice conversation can be performed.

Electronic Mail (E_mail)

• Electronic message transfer between two users through the Internet

• Messages include text, pictures, recorded voice

• Transmission rate is very fast

• An e_mail address is needed for sending

Gopher

• a part of the Internet that categorizes information in menus; separated from the WWW

• a menu-based program that enables users to browse for information on the Internet

• allows you to search a lists of resources and then helps to send the material to you

Telnet• A telnet can be made if an account exists in the

remote computer,and a connection is made through Internet with the provision of correct username and password

• Users are allowed to login any remote computers around the world. Computer used for telnet becomes a terminal for the remote computers

• Services provided by remote computers can be accessible at any other places.

File Transfer Protocol(FTP)

• allowing file transfer from point to point through Internet– you may upload their HTML documents to the

Internet for your own Web page– you may download any shareware/freeware

distributed by software developer for trialfrom the remote computer