Internet and World Wide Web 

The Internet

Introduction to the Internet

The Internet is often called the Net, the Information Superhighway or Cyberspace.

The Internet consists of thousands of connected networks around the world. A network is a collection of computers that are connected to share information. Each government, company and organisation on the Internet is responsible for maintaining its own network.

What the Internet Offers

Electronic Mail - Exchanging electronic mail is the most popular feature on the Internet.

Information - The Internet gives you access to information on any subject imaginable.

Programs - Thousands of programs are available on the Internet.

Entertainment - Hundreds of simple games are available on the Internet.

Discussion Groups - You can join discussion groups on the Internet to meet people around the world with similar interest.

On-line Shopping - You can order goods and services without ever leaving your desks.

Who Pays for the Internet

The Internet is made up of thousands of networks that belong to businesses, government agencies, colleges and universities around the world. The organisations pay to set up and maintain their own parts of the Internet.

How the Internet Started

ARPANET - In late 1960’s, the U. S. Defence Department created a network that linked military computers together. The network, ARPANET, was connected in a way that ensured if one section of the network was damaged, the remaining computers on the network would still be able to communicate with each other.

NSFNET - National Science Foundation created NSFNET in the mid-1980’s using the technology developed for ARPANET to allow universities and school to connect to each other. By 1987. NSFNET could no longer handle the amount of information that was transferred. The National Science Foundation improved the network to allow more information to transfer. This improved high-speed network became the Internet.

How Information Transfers

Packets - When you send information through the Internet, the information is broken down into smaller pieces, called packets. Each packet travels independently through the Internet and may take a different path to arrive at the intended destination. When information arrives at its destination, the packets are reassembled.

TCP/IP - Transmission Control Protocol/Internet Protocol (TCP/IP) is the language computers on the Internet use to communicate with each other. The TCP/IP divides information you send into packets and sends the packets across the Internet. When the information arrives at the intended destination, TCP/IP ensures that all the packets arrived safely.

Routers - A router is a specialised device that regulates traffic on the Internet and picks the most efficient route for each packet. A packet may pass through many routers before reaching its intended destination.

Backbone - The backbone of the Internet is a set of high-speed data lines that connect major networks all over the world.

Download and Upload Information - When you receive information from another computer on the Internet, you are downloading the information. When you send information to another computer on the Internet, you are uploading the information.

Getting Connected

Computer - You can use any type of computer, such as an IBM-compatible or Macintosh computer, to connect to the Internet.

Programs - You need special programs to use the Internet. Most companies that connect you to the Internet provide the programs you need free of charge.

Modem - You need a modem to connect to the Internet. Choose a modem of at least 28,800 bps, although a modem of a speed of 56,000 bps is recommended.

Internet Service Provider - An Internet Service Provider (ISP) is a company that gives you access to the Internet for a fee.

Types of Connection - There are three ways you can connect to an internet Service provider. A Point-to-Point Protocol (PPP) connection is the most popular and most reliable way to connect to a provider using a modem. Serial Line Internet Protocol (SLIP) and Compressed SLIP (CSLIP) are older and less reliable ways to connect to a provider.

The World Wide Web

Introduction to The Web

World Wide Web - The World Wide Web is also called the Web, WWW or W3. It is part of the Internet. The Web consists of a huge collection of documents stored on computers around the world.

Web Page - A Web page is a document on the Web. Web pages can include text, pictures, sound and video.

Web Site - A Web site is a collection of Web pages maintained by a college, university, government agency, company or individual.

Web Server - A Web server is a computer connected to the Internet that makes Web pages available to the world.

URL - Each Web page has a unique address, called the Uniform Resource Locator (URL). You can instantly display any Web page if you know its URL. All Web page URLs start with http (HyperText Transfer Protocol).

Hypertext - Web pages are hypertext documents. A hypertext document contains highlighted text that connects to other pages on the Web. You can select highlighted text on a Web page to display a page located on the same computer or a computer across the city, country or world.

Web Browsers

Web browser - A Web browser is a program that lets you view and explore information on the World Wide Web.

Popular Browsers - Microsoft Internet Explorer and Netscape Navigator.

Plug-Ins

Plug-Ins - A plug-in is a special program that a browser needs in order to display or play certain types of files on the Web. A plug-in performs tasks a browser cannot perform on its own.

Popular Plug-Ins - Acrobat Reader, Crescendo, QuickTime and Shockwave.

Web Page Features

Frames - Some Web pages divide information into rectangular sections, called frames. Each frame displays a different Web page.

Forms - Some Web pages include forms that let you enter information. The information you type into a form travels across the Internet to the computer that maintains the page.

Tables - Some Web pages display information in tables. A table organizes information into an easy-to-follow, attractive format.

Security on the Web

Many Web pages require you to enter confidential information about yourself to use the services they offer. There are secure pages on the Web that will protect confidential information sent over the Internet.

Secure Web Pages - Secure Web pages work with Web browsers that support security features to create an almost unbreakable security system. When you connect to a secure Web page, other people on the Internet cannot view the information you transfer.

Visit Secure Web Pages - When a reader visits a secure Web page, the Web browser will display a solid key or a lock at the bottom corner of the screen. This indicates that the Web page is secure.

Multimedia on the Web

Multimedia is an effective way of attracting attention to information on a Web page. A Web page can contain text, images, sound, video and animation.

Transfer Time - Some files take a while to transfer to your computer. A Web page usually shows you the size of a page to give you an indication of how long the file will take to transfer.

Text - You can view documents on the Web such as newspapers, magazines, etc. Text transfers quickly to your computer, so you do not have to wait long to read text on a Web page.

Images - You can view images on the Web such as album covers, pictures of celebrities , etc.

Sound - You can hear sound on the Web such as TV theme songs, movie soundtracks, sound effects, etc. You need a sound card and speakers to hear sound on the Web.

Video and Animation - You can view video and animation on the Web such as movie clips, cartoons, etc. Video and animation files often take a while to transfer to your computer.

RealAudio

RealAudio is a program that lets you listen to sound such as live radio shows, music or interviews on the World Wide Web.

Streaming Audio - RealAudio uses a system called streaming audio to transfer sound to your computer. Other programs that play sound must transfer the entire sound file to your computer before you can listen to the sound. With streaming audio, you can listen to the sound while the file is transferring.

RealVideo

RealVideo is a technology that displays moving video images on the World Wide Web.

Streaming Video - RealVideo uses a system called streaming video to transfer information from a content provider to a RealVideo player on your computer. Streaming video lets the RealVideo player start displaying the video information while the file is still transferring to your computer. Other programs require the entire video file to transfer before you can watch the video.

Java

Java is a programming language that allows you to create animated and interactive Web pages. A Java program used in a Web page is called a Java applet.

How Java Works - Java applets are stored on a Web server. When a reader displays a Web page containing a Java applet, the applet transfers from the Web server to the reader’s computer and then runs. Some Java applets take a long time to transfer.

Web Browsers - Before viewing a Java applet on a Web page, a reader must have a Web browser that can run Java applets. Most new Web browser can run Java applets.

Reasons for using Java -

Web Page Enhancements: Most people use Java applets to enhance their Web pages. Many applets are used to display moving text or simple animation.

Interactive Web Pages: People often include Java applets in their Web pages to allow readers to interact with each other on the Web. Some Java applet allow readers to play playing games or chat with other people.

Programs: Java is also used to write complex programs such as word processing, spreadsheet and drawing programs. These types of Java applets are very large. Most people do not include this type of Java applet in their Web pages because the applets take too long to transfer.

JavaScript

JavaScript is a programming language that is mainly used for Web page enhancements, such as displaying scrolling messages and fading-in Web pages. Although the names are similar, JavaScript and Java have very little in common. JavaScript is easier to learn than Java.

How JavaScript Works - JavaScript instructions are placed in the HTML document.

Web Browsers - Before viewing JavaScript on a Web page, a reader must have a Web browser that can run JavaScript instructions. Most new Web browsers can run JavaScript.

ActiveX

ActiveX is developed by Microsoft to help improve your Web pages.

Reasons for Using ActiveX - ActiveX is commonly used in Web pages to add pop-up menus that instantly display a list of options. ActiveX is also used to include animated images and information from other programs, such as Microsoft Word or Microsoft Excel, in Web pages.

Web Browsers - Before viewing a Web page that includes ActiveX features, a reader must have a Web browser that supports ActiveX. Microsoft Internet Explorer has built-in support for ActiveX.

VRML

Virtual Reality Modeling Language (VRML) allows you to view three-dimensional objects and environments, called VRML worlds in Web pages.

VRML Viewers - A VRML viewer lets you use a mouse or keyboard to move through three-dimensional areas or walk around objects in a VRML world. To display a VRML world, a Web browser must support VRML. Most new browsers support VRML.

Virtual Objects - You can view a virtual object from any angle. You can walk around a virtual object and move closer or further away from the object. A virtual object can be a car, truck, plane, lamp or any other item in the real world.

Reasons for using VRML -

Entertainment: VRML is used to create three-dimensional towns, movies and games.

Product Demonstrations: Companies often use VRML to show their products.

Training: VRML worlds allow people to use the Internet to train at home instead of going to a classroom.

Search the Web

There are many free services you can use to find information on the Web. These services are called search tools. A search tool catalogs Web pages to make them easier to find. Some search tools record every word on a Web page, while others only record the name of each page.

How Search Tools Find Web Pages -

There are two ways a search tool finds pages on the Web.

Spiders: Most search tools have automated robots, called spiders, that travel around the Web looking for new pages.

Submissions: People submit information about pages they have created.

Search Methods -

There are two ways a search tool can help you find information on the Web.

Search by Category: You can browse through categories such as arts, science and sports to find information that interests you.

Search by Topics: You can search for a specific topic that interests you.

Popular Search Tools - Alta Vista, Infoseek, Lycos and Yahoo.

Create Web Pages

You can create and publish Web pages to share information with people around the world.

Why Publish? - Individuals publish on the Web to share their favourite pictures, hobbies and interests. Companies publish on the Web to promote their businesses, advertise products and publicise job openings.

Web Page Organisation - Before you start creating Web pages, decide what ideas you will discuss and how the ideas relate to one another. Break up your information so you discuss only one major idea on each page. You may find it helpful to first sketch the design of your pages on paper.

HTML - HyperText Markup Language (HTML) is a computer language used to create Web pages. An HTML document has the extension .html or .htm (example: index.html). You can create HTML documents using a text editor or word processor. You can also create HTML documents using HTML editors, such as Microsoft FrontPage or Netscape Gold.

Images - You can add images to your Web pages to make the pages more attractive. Avoid placing a large number of images on your Web pages. Images increase the time it takes for pages to appear on the screen.

Links - You can place links on your Web pages that connect to other pages you have created. This helps readers flip through your Web pages. You can also place links on your Web pages that connect to pages maintained by other organizations. This gives readers instant access to related information.

Publish Web Pages - Once you’ve created your Web pages, you can publish the pages by transferring the pages to a Web server. The service that connects you to the Internet may offer space on its Web server where you can store your Web pages free of charge. The service may limit the amount of space you can use. After you publish Web pages, make sure you keep the information on the pages up-to-date. Incorporate feedback you receive from readers and try to improve the content and design of the pages whenever possible.