The Internet: A Brief History

The Internet was originally designed by the US Department of Defence as a 'resilient' communication system, which could resist attack on communication nodes. Previously, systems relied on one central computer to send information to others. The Internet (then called ARPANet, for Advanced Research Projects Agency Network) used 'peer-to-peer' networking - a series of computers where each machine had responsibility for checking the network and its communications.

Since the early 1980s, when it was used predominantly by academics and scientists, the growth of the Internet has been exponential - over 30 million users in 1995. The Internet has been called a 'network of networks' - the term Internet covers hundreds of smaller localised networks which can be connected using it.

The Internet operates in a similar way to the telephone network, and uses much of the existing cabling. The major difference is: with voice signals, while you talk, one circuit or phone line is exclusively used for that call (called 'circuit switching'). When computers communicate, they use a 'packet switching' procedure, sending small 'packets' of data through the network.

In effect, this means no single computer has a monopoly over phone line usage, the lines being 'multiplexed' - any number of packets can be sent at the same time. Each packet has its destination address included in it, and is sequentially numbered. In this way, they can be sent in any order and reassembled at the other end. It also means that information can be sent via a variety of paths to get to the same destination.

This works because all computers connected to the Net speak the same type of language - TCP/IP, or Transmission Control Protocol/Internet Protocol. TCP regulates how the computers talk to each other and share information; IP regulates the addresses of computers. This also allows different types of computer to interact. For example, a message typed in on an Apple or PC could be read by a UNIX mainframe computer and vice versa.

The arrangement between the machines is often called Client/Server. The Server is the machine sending the information, the Client is the machine receiving the information.

Another term used is Local/Remote Host. The 'local' machine is yours (or the service provider's); the 'remote' host is the one connected to its service. This allows you to access directories, programs and software on the 'remote' machine.

File Transfer Protocol, or FTP is the most common method for transferring information on the Internet. It refers to two different items: The communication protocol (a standard way for computers to talk to each other) and the actual software used to transfer files.

Contents: World Wide Web

Skill Check: World Wide Web