Internet  Major:Safety science and engineering  Author:jiangqian( 蒋乾 )

Concept  web servers

Concept  web browsers

Concept Languag:HTML Html language is designed to specify the logical organisation of a document, with important hypertext extensions. To sum up,the information of the browsers and web servers commucate with each other through the language.

Concept  Browsers are communicating client-server computer programs for distributing documents and information,generally called web data,over the Internet.  Web data are marked up in the HTML language for presentation and interaction with people in web browsers.  Each web sever uses an IP addresss or domain name as well as a port number for its identification.  People use web browsers to send data requests to web servers with the HTTP protocol,and the web servers running on server computers either retrieve the requested data from local disks or generate the data on-the –fly, mark up the data in HTML,and send the resulting HTML files back to the web browsers to render...

function You can use Internet in diffent ways:  communicate with friends  search for informations  buy online  work from home  play online games  download video/music/ebooks/applications  update your software (driver updates, virus definitions)  many, many other ways

function  A Source of Information Internet services such as Newsgroups and the World Wide Web (WWW) hold vast amounts of information, much of which is freely accessible and available 24 hours per day. The information may be of varying quality but the diversity of available information is extraordinary; it includes IT, legal, financial, art, sport and entertainment. Every piece of information stored on the Internet has a unique address known as a Uniform Resource Locator (URL). Search engines provide a mechanism for locating information. While a lot of this information is freely available, it may also be viewed as a commodity and some information on the Internet is available only by subscription.

function  A Means of Communicating Internet services such as Newsgroups and provide the Internet communications services. The Internet is made up of thousands of networks located around the world, which are interconnected using routers and Wide Area Network (WAN) links. It is spread across more than 150 different countries with the Internet forming the largest WAN in existence. There is no restriction on the type of operating system which may be used - any computer system can connect to the Internet either to provide information for others or to browse for information as a user. All the diverse networks and systems are linked by common protocol (language); the TCP/IP transport protocol provides the means for communication, while application protocols such as SMTP, POP and NNTP provide the higher level services. Together, these protocols allow diverse systems to share data and to communicate.

function  Marketing - A Medium Through Which to Conduct Business Through the development of e-commerce, the Internet has established an electronic global world-wide market that operates 24 hours a day. Organizations and individuals are able to market goods and services, while purchasing is supported by facilities such as digital signatures and encryption. Developments in software mean that an increased number of facilities are becoming available all the time. The mid-90s have seen the development and success of company Intranets. Internet technology has been applied to a LAN or WAN within an individual company, with the object of sharing information easily. Extranets have also been developed to allow organizations to share private information using the public Internet. Both Intranets and Extranets are discussed later in this module. The rapid growth of the Internet has revealed weaknesses in its infrastructure and considerable investment is currently taking place to improve performance and reliability.

 Thank you !