E-Learning Online

• Networks

A computer network consists of two or more computers connected so that they can exchange data and programs.

 

Each computer has a network address that the other computers use to access it. Usually the computers share a printer. There may be an especially powerful computer called a server whose hard disk holds application programs and data that the other computers are expected to need.

 

Each computer in a network has a network interface card. This is an input/output device that sends and receives data over cables. The network interface cards of computers on a network are connected together with cables.

 

• World-Wide Web

 

The Internet provides the hardware and the information transmission protocols for the World-Wide Web. Data intended for the Web is transmitted over the Internet just like any data. What makes Web data special is that it is intended for Web browsers (such as the one you are probably looking at). A browser is a program that can read Web pages and display them in a nicely formatted way. A Web page is a package of data that contains information on how it is to be displayed on a monitor. This information is given using a language called Hypertext Markup Language (HTML). If you want to see an example of this, left-click on View in the menu at the top of your Web browser, then left-click on Source. This will bring up a new window with the HTML of this page in it. After you are done viewing, close the window by clicking on the close button in its upper right corner (the button marked with X).

 

    Hyperlinks

 

 

One Web page is connected to another with a hyperlink. If you have been reading these notes over the Web, you have been linking between Web pages by using hyperlinks. A Web browser usually displays a hyperlink in a distinguishing color (usually blue). When you click on it, the browser asks the operating system to get a particular Web page from another computer connected to the Internet.