Part5: The Internet

What is the Internet?
The Internet is a global connection of computers. These computers are connected via a huge network of telecommunications links. The Internet allows you to access to a whole resource of data and information stored at different sites (called hosts or servers) and locations all around the world. The communication links that interconnect each host computer use a common method of transmission, known as TCP/IP, which stands for Transmission Control Protocol/Internet Protocol.

Each computer connected to the Internet (by the way, it is always spelt with a capital I) can act as a host. A host computer provides information for other people to access and retrieve.

History of the Internet
The Internet had its origins in the cold war between Russia and America during the 1960's. Concerned about the survivability of its communications in the event of a nuclear strike, the US air force needed to ensure that it could still communicate with its forces.

The proposed system, developed by Paul Baran, suggested a decentralized system that would still operate even if parts of it were destroyed.

All interconnections in the network could send and receive messages, forwarding them onto other interconnection points (called nodes) until the message reached its destination.

Information would be sent in little packets, each packet would be self contained and have its own address information. Packets would travel from node node, each node deciding how to send the packet to the next available node. Even if some nodes were destroyed, the message could still be sent by an alternative route.

In this way, the network would withstand a nuclear strike. After implementing the network, it was known as ARPANET and used by the US military and US universities. Gradually, as more and more connections were made, it has evolved to the Internet.

Services available on the Internet
The Internet provides for a wide range of services. Some of these are listed in the table below.

Service	Description of Service
EMAIL	Electronic mail. Permits the sending and receiving of messages to other users connected to the Internet.
FTP	File Transfer Protocol. A means of sending and receiving files from one computer to another.
GOPHER	An early form of representing information as graphical icons or symbols, that could be displayed in a window and then downloaded. It has been replaced by the WWW
USENET	A number of discussion groups that allow users to post questions and replies, sorted by topic. Also known as news.
WWW	World Wide Web. Accessed using a web browser such as Netscape Navigator or Internet Explorer, a means of locating and displaying information located on the Internet.

Internet Service Providers
Internet Service Providers (ISP's) are companies which provide others with access to the Internet. This can be via dial-up connection using a modem, or using an ISDN or permanent high speed connection. Various charging levels may exist, but a popular method for home users is flat rate (per month unlimited time and data amount).

Each user can access the Internet through connection on an existing network or via a modem from a remote site such as a private residence. The data and information that can be accessed on the Internet comes in numerous different formats and there a wide range of applications that interpret the information for the user.

Intranets
An Intranet is an internal TCP/IP network which is not visible outside the company or department where it resides, essentially being used as a repository of local documents. It uses the same technology as web servers that the Internet uses. Companies today deal with masses of information. This information is in many forms, typically, to name a few

Companies can no longer justify printing this information and keeping it up to date. Using an Intranet solves this problem, by providing a single document which can more readily be kept up to date. By storing this data on an Intranet, users get access to the information and can search this information faster and with greater ease than before.

Something to think about
Think of some other applications that could be used on a company Intranet. What value might a company have in establishing an Intranet? What problems do you think a company Intranet might suffer from? Consider issues of user support, hardware and software requirements, updating of information, and security of the information on the Intranet.

Summary
Traditionally the Internet was purely a text based global pool of information and access was either limited or required a certain specialised knowledge. The development of the Internet today has ensured that information now comes in other formats such as graphical, audio and animated images, and the interface for such information is now a lot more dynamic and user friendly.

Commercialization of the Internet is evidenced by the increasing presence of large multinational corporations. The Internet continues to grow each year, with more and more people becoming connected and more and more services becoming available.

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