Explain about internet. AND CONCEPTS OF INTERNET
Computers in an office are networked using LAN (Local Area Network). Computers in different locations are connected by WAN (Wide Area Network). Both these network systems are not for public use and have limited usage. The Internet is a network of thousands of networks. Millions of computer networks are connected to the Internet network and are available to the public.
Internet was invented by American Department of Defence in 1969. Even computers that use different hardware and software can be connected to the Internet.
Minimum requirements for internet :
A computer
A telephone line
A Modem
An account with an Internet Service Provider (ISP)
The simplest way to connect the computer to the Internet is by using a telephone line. A modem (Modulator-Demodulator) converts the digital signals from the computer into analog signals that the telephone lines use. The signals are transmitted over the telephone line and are received by the modem at the other end. These signals are then reconverted into digital signals that the receiving computer can understand.
The computer should be connected to an Internet Service Provider. VSNL, MTNL, Tata Telecom and Satyam Online etc. are some important ISPs available. The ISP provides username, password, dial-up numbers from the ISP. Usually the ISP gives an auto-dialler which can be used for connecting to Internet.
The World Wide Web (Popularly known as Web) : The web is organised like a library. It has websites and each web site has a title and a number to identify it. The title of a web site is called a URL (Uniform Resource Locator). It is easy to remember the URL of the web site than its number. The URL of a web site is also called its address.
When you open a web site, you see the contents of that window. This is a web page. The first web page of a web site is called the home page of that web site. A web page cvan contain text, pictures, audio visuals etc., These are called links. Links are usually underlined or in a different colour. When you move your mouse pointer over a link, the arrow changes to a picture of a small hand. Using these links from the home page you can select and view the other web pages containing the topic you want.
A browser is an application software that helps you search, view and read web sites on the web. Internet Explorer (IE) and Netscape Navigator are the most commonly used browsers. To see the web site of your choice, you will have to type the address of that web site in the browser. This address is the URL of that web site.
Search Engines : These are web sites available on the internet that provide information on any topic that you want. Search Engines contain a programme that collects information from other web sites. This information is then stored according to the category it belongs to. Eg. Web sites about music will be stored in a category named Fine Arts. Examples of popular search engines are Yahoo, Alta Vista and Google. To view a site of your choice, click on the Address box and type the URL of that site and click on Go or press .
The information required from the internet can be copied on to your document. This is called downloading. You can also copy and paste text from a web page into your document after highlighting it.
