In this post I am going to to describe about what is computer network how does it work, how does it functions etc
So lets start,
Introduction A Computer Network
- Data Sharing: Information available in one computer can be accessed by another computer.
- Hardware Sharing: Many computers can use an expensive device available at one site (i.e. laser printer, plotter, scanner, hard disk, etc.).
- Communication: Data in one computer can be passed to another computer via communication device such as MODEM (Modulator and DE-ModuIator) and telephone lines. Networking allows a user to send electronic mail (e-mail) to each other. People can communicate with others by typing messages on computers. On the other hand , they can send a text or graphics on the network.
- LAN (Local Area Network): It is a computer network that spans relatively a small area. Most LAN's are confined to a single building or group of buildings.
- MAN (Metropolitan Area Network): The network size falls between LANs and WANs. A MAN typically covers an area of between 5 and 50 km diameter. Many MANs cover an area the size of a city, although in some cases MANs may be as small as a group of buildings.
- WAN (Wide Area Network): It is a computer network that covers relatively a large geographical area. Typically, a WAN consists of two or more local area networks (LANs). Computers connected to a wide area network are often connected through public networks, such as the telephone system. They can also be connected through leased lines or satellites. The largest WAN in existence is the Internet.
The Internet
The Internet is a computer network made up of thousands of networks worldwide. It is "a network of networks". In the Internet the computers are connected to each other with network cables, telephone lines, microwave dishes, satellites, etc. some computers (Servers) on the Internet store documents, sound files, video clips, program files, electronic shopping centers, animations, pictures and other information that can be stored and presented electronically. All these resources are available to all computers connected to the Internet. You can communicate with anyone on the Internet by sending e-mail, posting messages in newsgroups, chatting on various chat areas and even telephoning and videoconferencing over the net.
Hardware and Software Required for Internet Access are:-
- A personal computer with a MODEM.
- Operating system Installed.
- Internet Browser software such as Explorer or Firefox.
- Telephone lines.
- Internet service account (ISP account).
Some common Internet services are listed below:
- WWW: World Wide Web is a large information source for the web users around the world.
- E-mail: Electronic mail services users to send messages to each other.
- FTP: File Transfer Protocal allows users to transfer files on the Internet.
- Internet chat: This service allows users to chat on the Internet.
- News: This service provides up-to-date news and information.
Some Popular Term Used In Internet
URL (Web Address)
Each web page on the web has a unique address. This address is called a URL (Uniform Resource Locator). The URLs of web pages start with http://where it stands for Hyper Text Transfer Protocol. To view a particular website, you will have to provide an address Ora URL of that website.
Web Browser
The software used to navigate through the web is known as a browser. The most Popular browsers today are Microsoft Internet Explorer and Netscape Navigator. Web browsers support not only web documents but also other internet services like FTP, Telnet and News. Using web Browser you can move to a specific page by typing its address (URI). Some of the popular web browsers are: Mozilla Firefox, Opera, Google Chrome etc.
Browsing the Sites Using Web Browser
- Start your web browser.
- When you open the Internet Explorer browser, the home page of Microsoft will open by default. If you have the Netscape browser, the home page of Netscape Incorporation opens on your screen by default.
- In the address box of the browser you can see URL of the website that is currently open. To move to another site, you have to type its URL. For example, let us type the URL of another site, say http://www.youtube.com.
- To do so, move the mouse-pointer inside Address Box and click the left mouse button. Immediately, a blinking cursor appears at that point.
- Now type the URL http://www.youtube.com and then press the Enter Key. This address gets highlighted and after a few moments, the website of Youtube appears on your screen.
As a book is the collection of many pages so, the web site is the location where collection of web pages resides. The web sites are developed by different organization, universities and goverment offices so as to provide information to the people. Each of the website consists of web address. This address helps user to locate the websites. For example: www.nepalnews.com, www.webopedia.com, www.howstuffswork.com etc.
Search Engine
Search Engine is a special type of web-site that lists of documents, most commonly those on the World Wide Web (WWW), and the contents of those documents. Search engines respond to a user entry (keyword), by searching the lists and displaying a list of documents (called Web sites when on the WWW) that match the search query. Some search engines include the opening portion of the text of Web pages in their lists, but others include only the titles or addresses (known as Universal Resource Locators, or URLs) of Web pages. Some popular search engines are Google, Yahoo, MSN, Web Crawler, Spider etc. Here we are going to have brief introduction on some of the popular used website. They are:
- Google: It is one of the mostly used search engine owned by the Google Inc. and mostly used search engine among all. Generally it hunts for the text in the web pages but besides that it provides 21 special features. Some of them are: weather forecast, maps, time zones etc.
- Yahoo: It is second most used search engine owned by Yahoo! Inc. It also lets user search various items to search ranging from web pages, images, videos to books and other items. Yahoo is also called a web-portal.
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