The Internet is a network of computers that share a common communications protocol (TCP/IP), which enables computers of different types to exchange information. It is this cross-platform compatibility that makes the Net so powerful and has caused it to grow at such an exponential rate.
So, what is a network? It's more than just linking things together; it's the way they're linked together. In the case of the Internet, it's the way thousands of computers are linked together. This seems very basic, and people use the term "network" every day, but few people understand the concept.
Imagine you had four computers and that each computer had a line running to each other computer, as in Figure 1.1. Each computer could transfer information to any other computer, but the cables get messy and expensive. It's similar to having a separate telephone for each person you call, rather than having one telephone by which you could call any other.
Figure 1.1. An inefficient computer network.
In Figure 1.2, each computer only connects to one line. This is a network (were there more computers, the "net" aspect would become more apparent). In a network, each computer has access to the information on the line. In order to keep things straight, each computer must be given a name or address.
Figure 1.2. A simplified computer network.
Imagine that Computer C wants some information from Computer A. Computer C sends a message like "Computer A, send me file xxx12." Although the other computers have access to the request, they ignore it because it's addressed to A. This addressing scheme is called a protocol. The Internet Protocol (the IP in TCP/IP) uses a series of numbers to designate an address. This is called the IP address, and each computer connected to the Net has an IP address.
Who Made the Internet?
Many believe the Internet is a new concept, but it actually originated in the 1960s as the Advanced Research Projects Agency Network (ARPAnet), funded by the Department of Defense. ARPAnet enabled a global network of government personnel, scientists, and researchers to collaborate and exchange critical information with each other.
The idea was that by sharing research, scientists from different disciplines could avoid reinventing the wheel (no offense to Zog). This is to say that a group working on a new type of rocket engine could, rather than requesting literature via mail or conducting research themselves, simply connect to a different computer and download the information they wanted on, say, ignition switches.
In the 1980s, the National Science Foundation (NSF) gave the ARPAnet a complete upgrade by implementing a more modern, higher-speed network. This upgraded architecture was given the name Internet, which linked government supercomputers, educational institutions, and research facilities. As a whole, the Internet functioned as a broad-based educational and research network.
There were originally four basic functions on the Internet: e-mail, Usenet, Telnet, and file transfer. E-mail is, obviously, electronic mail— direct communication. Usenet is an electronic bulletin board, a public forum where people can post and view messages. Telnet enables a person to actually use another computer (the TCP part of TCP/IP stands for Transfer Command Protocol) for such things as accessing databases. File transfer enables people to send computer files from one system to another.
As it stands now, the Internet is an international network connecting tens of millions of people around the world. Governments, universities, private citizens and, of course, businesses use the Net every day for communication, education, entertainment, and commerce. You'd think that the people originally involved with the Net would have been happy to see it grow so quickly, many weren't.
By 1992, when this timeline ends,
- the Internet has one million hosts
- the ARPANET has ceased to exist
- computers are nine orders of magnitude faster
- network bandwidth is twenty million times greater.