Internet And Its Features

Web

• It is an abstraction(concept) and common set of services on top of the Internet.
• It is a set of protocols and tools that let us share information with each other.

World Wide Web

• It is a collection of linked documents, or pages, stored on millions of computers and spread over the entire Internet.
• The term “World Wide Web” comes from the belief that individual nodes of information are linked with hypertext, and this creates a “web” of information.
• The documents on the web are written in HTML-that defines their appearance and layout, and creates the links to other documents. These links are known as hypertext link or hyperlink.
• In 1989, Tim-Berners-Lee of European Particle Physics Lab(CERN) in Switzerland has developed WWW.
• The purpose of WWW is to provides a network of interactive documents and the software to access them.
• It is based on documents called pages that combine text, pictures, forms, sound, animation and hypertext links

Features of WWW

• The ability to easily deliver information in any format, to/from a wide range of computing platforms.
• Simplified access to the Internet.
• The easy availability of extensive information on a wide range of topics.
• The Web is interactive.

Uses of WWW

• Education Tool
• Search Tool
• Business Tool

Web Browser

• Web Browser is an application that uses information stored at locations around the World Wide Web.
• Browser is a piece of software that acts as an interface between the user and the inner-workings of the

Internet.

• It is also referred to as Web clients or universal clients.

- Functions:

• Contact a web server and sends request for information.
• Receives the information and then displays it on the user’s computer.
• Browser fetches the requested page, interprets the text and formatting commands that it contains, and displays the page properly formatted on the screen.
• Voice based browsers are also being developed.
• When given the URL of a document, the browser becomes a client that contacts a Web server on the computer specified in the URL to request the documents.
• Browser consists of set of clients, a set of interpreters and a controller to manage them.
• The controller forms a central piece of browser.
• When a browser interacts with a web server, two programs follow the HTTP.
• HTTP allows a browser to request a specific item, which the server then returns.

How to access the WWW : Web Browsers?

• Graphical
• Text

Web Server

• Computers that are connected to the Internet and that contain files that their owners have made publicly available are called web servers.
• Any computer can be turned into a Web server by installing web server software and connecting the machine to the Internet.

• Ex:
• Apache
• Microsoft IIS (Internet Information Server)
• A server is a member of a class of programs in a modern software architecture called client/server software architecture, in which all applications have two components:
• The client component
• The server component.

Server

• A server is on large Computer
• Server is passive
• Runs continuously waiting for requests
• Runs in background and interfaces only with other software(Clients) and rarely interfaces directly with users.
• Server must runs multiple tasks concurrently
• Responsible for transmitting the document

Client

• A Client is on small computer & runs a multiple instance
• Client is active
• Runs only on-demand
• Client is invoked by a user and takes commands from the user
• A Client usually works for one person and does one thing after another in sequence
• Responsible for displaying document

Web Pages and Web Sites

• Web page is a page containing information and instructions.
• The information can be text, images,audio or video.
• The instructions are specified in HTML.
• A Web site is a collection of related Web Pages(files) stored on a Web Server.
• Web sites are hosted on Web Servers.