Internet

Contents

1. Internet

Internet is the worldwide collection of networked computers which are able to exchange information with one another very quickly.  The computers that make up the Internet exchange information using the same cables and general technology that home phone uses.  Most people use the Internet in two ways, e-mail and the World Wide Web.

The Internet, sometimes called simply "the Net," is a worldwide system of computer networks - a network of networks in which users at any one computer can, if they have permission, get information from any other computer (and sometimes talk directly to users at other computers). It was conceived by the Advanced Research Projects Agency (ARPA) of the U.S. government in 1969 and was first known as the ARPANET. The original aim was to create a network that would allow users of a research computer at one university to be able to "talk to" research computers at other universities. A side benefit of ARPANet's design was that, because messages could be routed or rerouted in more than one direction, the network could continue to function even if parts of it were destroyed in the event of a military attack or other disaster.

The principal Internet backbone was NSFNET (National Science Foundation Network).

How can an Internet Connection be established?

For an internet connection we require a telephone line, a modem and an ISP. A Modem (Modulator Demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.

In this context Modem is used to convert the digital signals from the computer into analog signals that the telephone lines use. The signals are then transmitted over the telephone line and thus are received by the modem at the other end. These signals are again converted into digital signals that the computer can understand.

The computer should be connected to an Internet Service Provider. An Internet service provider (ISP), also sometimes referred to as an Internet access provider (IAP), is a company that offers its customers access to the Internet. The ISP provides its customers with username, password. The ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol datagram’s, such as dial-up, DSL, cable modem, wireless or dedicated high-speed interconnects.

Uses of Internet:

Sharing and exchanging information

Information is probably the biggest advantage internet is offering. The Internet is a virtual treasure trove of information. Any kind of information on any topic under the sun is available on the Internet. The search engines like Google, yahoo is at service on the Internet. However, we must carefully check the source (website) and quality of the information. An example of good source of general information is wikipedia.org. Almost any type of data on almost any kind of subject can be found on net. There is a huge amount of information available on the internet for just about every subject known to man, ranging from government law and services, trade fairs and conferences, market information, new ideas and technical support, the list is end less.

Communication and Social Networking

Internet chat and instant messaging systems allow people to stay in touch in a convenient way while working at their computers. Messages can be sent and received instantly. In addition, these systems also allow file transfer, as well as voice and video contact.

Social networking websites allow people to stay in touch with friends and family, and knowing their activities by viewing their profiles. The concept of a social networking website is to store people’s profiles and connecting them between one and another. A personal profile can include pictures and videos to be shared.

With help of such services, it has become very easy to establish a kind of global friendship where people can share thoughts, can explore other cultures of different ethnicity.

Remote Access

Computer users can easily connect to other computers and information stores around the world using the internet. The access can be done with or without security, authentication and encryption, depending on the needs.  

Remote access is encouraging new methods of working from home and information sharing in many businesses. Using Virtual Private Network (VPN), a businessman can use a remote desktop session to access his PC in the other side of the world.

VoIP (Voice over Internet Protocol)

It started from an optional two-way voice chat provided by some of the instant messaging systems that started around the year 2000. The benefit of VoIP is that it can be free or cost much less than a normal telephone call, because the Internet carries that voice traffic. VoIP is surely a cheap solution for long distance call.

E-commerce

Ecommerce is the concept used for any type of commercial maneuvering, or business deals that involves the transfer of information across the globe via Internet. It has become a phenomenon associated with any kind of shopping, almost anything. Just we need to place an order and Ecommerce with its giant tentacles engulfing every single product and service will make available at our door steps. It has got a real amazing and wide range of products from household needs, technology to entertainment.

6.1      Basic Services

1) File Transfer Protocol

FTP is an acronym that stands for File Transfer Protocol. An FTP client is a program that allows to easily moving files from one computer to another on the internet. Moving a file from a remote computer to ones own computer is known as downloading the file. Moving a file from a ones own computer to a remote computer is known as uploading the file.

In the case of creating a Web site, this means that if user creates the pages for his/her site on the computer, either using a text editor or some other Web page editor, then he/she need to move it to the server where his/her site will be hosted. FTP is the main way to do this.

Resources available via FTP

Freeware

When we download freeware, the author continues to carry the copyright to the software, but permits to use the program for free. Freeware can be shared by user with others as long as he doesn’t sell it.

Public Domain

The Public domain software can be used freely. The creator carries no copyright, and has released it for anyone to use. There are no limits on distribution or sale--and anyone can modify the program. 

Shareware 

When Shareware is downloaded, the authors continues to carry the copyright to the software but are permitted for short-term use of the program for evaluation purposes. At the end of evaluation period, user must either pay the copyright holder for the program or destroy all copies made out of it. 

2) Telnet

It is a terminal emulation program for TCP/IP networks such as the Internet. The Telnet program runs on user computer and connects the PC to a server on the network. User can then enter commands through the Telnet program and they will be executed as if user was entering them directly on the server console. This enables you to control the server and communicate with other servers on the network. To start a Telnet session, user must log in to a server by entering a valid username and password. Telnet is a common way to remotely control Web servers.

3) World Wide Web

The World Wide Web (The Web) is the most popular and promising method of accessing the Internet.  The Web lets people, organizations and companies publish information for other people to see.  This makes the Web a very useful tool for finding information on just about any topic.

The Web is a large number of computer documents or "Web pages" that are stored on computers around the world and are connected to one another using hyperlinks.  These Web pages can be seen by anyone through their computer's "Web Browser," which is the program being used now. A group of Web pages that follow the same theme and are connected together with hyperlinks is called a "Web site."  Web sites and Web pages are written in a coding language that makes it possible to add pictures, sound and interactivity to plain old text, making people's reading experience more exciting.

The server uses a protocol called HTTP or Hyper Text Transport Protocol. This is the protocol that is used to carry traffic between a Web browser’s computer and the Web site. The standard for creating hypertext documents for the WWW is Hyper Text Markup Language or HTML. It is the universal language of the Web in which all pages are written. HTML essentially codes plain text documents so they can be viewed on the Web.

Web Browsers  

Web browsers are programs used to explore the Internet. Browsers enable a user to visit a server computers site directly and access information stored on it by specifying its URL (Universal Resource Locator) address.URL is an addressing scheme used by WWW browsers to locate sites on the internet.  There are many Web browser programs available including Netscape Navigator, Internet Explorer, Mozilla Firefox and Opera. Internet Explorer is the Internet browser made by Microsoft and comes with Windows operating system.

Search Engines

A search engine is a Web site that lets user search the Internet for Web sites on specific topics.  Search engines turn the web into a powerful tool for finding information on any topic. 

4) Email

E-mail or electronic mail is one of the most popular uses of the Internet today. E-mail allows user to exchange messages with friends who are connected to the internet anywhere in the world.  The advantages of e-mail over regular mail are that it is free, it is delivered almost instantly and user can attach all types of files to the messages. 

E-mail is an asynchronous form of communication, meaning that the person whom user wants to read the message doesn't have to be available at the precise moment when he sends the message. This is a great convenience for both the user and the recipient.

E-mail systems are based on a store-and-forward model in which e-mail computer server systems accept, forward, deliver and store messages on behalf of users, who only need to connect to the e-mail infrastructure, typically an e-mail server, with a network-enabled device (e.g., a personal computer) for the duration of message submission or retrieval.