Introduction to the Internet: Introduction

What is Internet:
The Internet is a computer network that connects millions of computers globally and provides world-wide communications to businesses, homes, schools, and governments.

The Internet, the international network of networks, is the name attributed to the myriad computers located worldwide that are connected (inter-networked) together using a common protocol called TCP/IP (Transfer Control Protocol/Internet Protocol).

Setting Up: The world is just a phone call away. With a computer and a modem, one will be able to connect to the Internet, the world's largest computer network (you may not even need the modem; many colleges and companies now give their students or employees direct access to the Internet).

A modem is a sort of translator between computers and the phone system. It is needed because computers and the phone system process and transmit data, or information, in two different and incompatible ways. Computers "talk" digitally; that is, they store and process information as a series of discrete numbers. The phone network relies on analog signals, which on an oscilloscope would look like a series of waves. When your computer is ready to transmit data to another computer over a phone line, your modem converts the computer numbers into these waves (which sound like a lot of screeching) -- it "modulates" them. In turn, when information waves come into your modem, it converts them into numbers your computer can process by "demodulating" them.

How the Internet Began:
The beginning of Internet technology can be traced back to 1969, when the Advanced Research Projects Agency (ARPA), funded by the U.S. Department of Defense, conducted research on networking. Their goal was to design a network that allowed computers on different types of networks to communicate with each other. The idea was to connect large defense contractors and universities doing military research.

ARPA wanted to see if computers in different locations could be linked using a new technology known as packet switching, which had the promise of letting several users share just one communications line. Previous computer networking efforts had required a line between each computer on the network, sort of like a train track on which only one train can travel at a time. The packet system allowed for creation of a data highway, in which large numbers of vehicles could essentially share the same lane. Each packet was given the computer equivalent of a map and a time stamp, so that it could be sent to the right destination, where it would then be reassembled into a message the computer or a human could use.

During the 1960s and 1970s, many computer networking technologies were created, each based on a particular hardware design. Some of these networks, called Local Area Networks (LANs), connect computers over short distances, using cables and hardware installed on each computer. Other larger networks, called Wide Area Networks (WANs), connect many computers over larger distances, using transmission lines similar to those used in telephone systems.

Although LANs and WANs made it much easier to share information within organizations, the information stopped at the boundaries of each network. Each networking technology moved information around in a different way, often based on the design of its hardware. A particular LAN technology could only work with specific computers, and most LAN and WAN technologies were incompatible with each other.

The Internet was designed to interconnect the different types of networks and allow information to move freely among users, regardless of the machines or networks they used. It did this by adding special computers, called routers, to connect LANs and WANs of different types. The connected computers needed a common protocol, a shared set of rules describing how to transmit data. The Internet designers called the new networking protocol TCP/IP (Transfer Control Protocol/Internet Protocol). TCP/IP is a system for transferring information over a computer network. Together, TCP/IP and the system of connected networks formed the Internet.

This system allowed computers to share data and the researchers to exchange electronic mail, or e-mail. In itself, e-mail was something of a revolution, offering the ability to send detailed letters at the speed of a phone call.

As this system, known as ARPANet, grew, some enterprising college students (and one in high school) developed a way to use it to conduct online conferences. These started as science-oriented discussions, but they soon branched out into virtually every other field, as people recognized the power of being able to "talk" to hundreds, or even thousands, of people around the country.

In the 1970s, ARPA helped support the development of rules, or protocols, for transferring data between different types of computer networks. These "internet" (from "internetworking") protocols made it possible to develop the worldwide Net we have today that links all sorts of computers across national boundaries. By the close of the 1970s, links developed between ARPANet and counterparts in other countries. The world was now tied together in a computer web.

In the 1980s, this network of networks, which became known collectively as the Internet, expanded at a phenomenal rate. Hundreds, then thousands, of colleges, research companies and government agencies began to connect their computers to this worldwide Net. Some enterprising hobbyists and companies unwilling to pay the high costs of the Internet access (or unable to meet stringent government regulations for access) learned how to link their own systems to the Internet, even if "only" for e-mail and conferences. Some of these systems began offering access to the public. Now anybody with a computer and modem -- and persistence -- could tap into the world.

In the 1990s, the Net grows at exponential rates. Some estimates are that the volume of messages transferred through the Net grows 20 percent a month. In response, government and other users have tried in recent years to expand the Net itself. Once, the main Net "backbone" in the U.S. moved data at 1.5 million bits per second. That proved too slow for the ever increasing amounts of data being sent over it, and in recent years the maximum speed was increased to 1.5 million and then 45 million bits per second. Even before the Net was able to reach that latter speed, however, Net experts were already figuring out ways to pump data at speeds of up to 2 billion bits per second -- fast enough to send the entire Encyclopedia Britannica across the country in just one or two seconds.

How It Works:
Unlike commercial networks such as CompuServe or Prodigy, the Internet is not run by one central computer or computers. This is both its greatest strength and its greatest weakness. The approach means it is virtually impossible for the entire Net to crash at once -- even if one computer shuts down, the rest of the network stays up. The design also reduces the costs for an individual or organization to get onto the network. But thousands of connected computers can also make it difficult to navigate the Net and find what you want -- especially as different computers may have different commands for plumbing their resources. It is only recently that Net users have begun to develop the sorts of navigational tools and "maps" that will let neophytes get around without getting lost.

Nobody really knows how many computers and networks actually make up this Net. Some estimates say there are now as many as 5,000 networks connecting nearly 2 million computers and more than 15 million people around the world. Whatever the actual numbers, however, it is clear they are only increasing.

Internet Services/Tools:

  1. Electronic Mail
    Sending Messages
    Discussion Lists
  2. Telnet
  3. FTP (File Transfer Protocol)
  4. Gopher
  5. World Wide Web (Web)

    Internet Browsers:

    Graphical: Web Browsers
    Text Only: Gopher client programs.
    Web Browsers:
    Mosaic (NCSA)
    Netscape Navigator (Netscape)
    Internet Explorer (Microsoft)
    Lynx (Text-only browser available in UNIX systems)

Introduction Electronic Mail Telnet FTP Gopher Web Browsers Glossary Sources Table of Contents

Last Updated: June 1, 1997