Internet

• Network of interconnected computers around the world.
• A network of computer networks which operates world-wide using a common set of communications protocols.
• a computer network consisting of a worldwide network of computer networks that use the TCP/IP network protocols to facilitate data transmission and exchange.
• Visualization of the various routes through a portion of the Internet:

What do we need to get connected to internet?

• Getting on the Internet requires:
• Computer
• Modem
• Telephone Line
• Internet Service Provider (ISP)
• Communication Software

Modem and Telephone Line

Internet Service Provider (ISP)

• An Internet Service Provider (ISP) is a company that allow you to use their internet connection for a price.
• When you register with an ISP the followings are given:
• Username
• A unique name that identifies you.
• Password
• A secret code that prevents other people from using your account.

Some Popular Internet Service Providers

• AT&T WorldNet
• Microsoft Network
• America Online
• In India:
• VSNL (Videsh Sanchar Nigam Limited
• MTNL (Mahanagar Telecom Nigam Limited)
• BSNL (Bharat Sanchar Nigam Limited)
• Satyam Onlile

Communication Software

• Computer needs communicate
• on software to allow you to get connected to, and interact with, the Internet.
• Communication software is of two types:
• Software that Helps Establish Basic Internet Connectivity
• Software that helps to browse, access e-mail etc.

World Wide Web

• The basic idea of the WWW was to merge the technologies of personal computers, computer networking and hypertext into a powerful and easy to use global information system.
• The World Wide Web, abbreviated as WWW and commonly known as The Web, is a system of interlinked hypertext documents contained on the Internet.
• With a web browser, one can view web pages that may contain text, images, videos, and other multimedia and navigate between them by using hyperlinks.

Hypertext

• Hypertext is text displayed on a computer or other electronic device with references (hyperlinks) to other text that the reader can immediately access, usually by a mouse click or keypress sequence.
• Apart from running text, hypertext may contain tables, images and other presentational devices. Hypertext is the underlying concept defining the structure of the World Wide Web, making it an easy-to-use and flexible format to share information over the Internet.

Web Browser

• A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web. An information resource is identified by a Uniform Resource Locator (URL) and may be a web page, image, video, or other piece of content.
• Example of Web Browser:
• Mosaic
• Internet Explorer
• Netscape Navigator
• Mozilla Firefox

Web Page and Websites

• W3 contains several millions of pages of information. Each of these pages is called a Web Page.
• A webpage or web page is a document or resource of information that is suitable for the World Wide Web and can be accessed through a web browser and displayed on a computer screen.
• A web page can contain text, pictures, sound, animation and video.
• A group of related web pages that are linked together form a Web Site.
• The first page of a web site is called the Home Page.
• The Home Page shown below is the Home Page of the official website of Tail Nadu Agriculture University.

Universal Resource Locator

Search Engine

• A web search engine is designed to search for information on the World Wide Web. The search results are usually presented in a list of results and are commonly called hits.
• Few examples of web search engines are:

Download this lecture as PDF here