The Internet

The Internet and World Wide Web

We begin with a brief history of the Internet and World Wide Web. We describe how Web documents are accessed and created, and define basic terms such as HTTP (HyperText Transfer Protocol) and HTML (HyperText Markup Language).

The World Wide Web cannot be appreciated, however, until you visit it yourself. Thus, the chapter also introduces Internet Explorer, the browser that was developed by Microsoft. As always, learning is best accomplished by doing, and so we include two hands-on exercises and provide our own guided tour so that you can experience firsthand what the excitement is all about.

The Internet

The Internet is a network of networks that connects computers across the country and around the world. It grew out of a U.S. Department of Defense (DOD) exper­imental project begun in 1969 to test the feasibility of a wide area (long distance) computer network over which scientists and military personnel could share messages and data. The country was in the midst of the Cold War, and the military imposed the additional requirement that the network be able to function with par­tial outages in times of national emergency (e.g., a nuclear disaster), when one or more computers in the network might be down.

The proposed solution was to create a network with no central authority. Each node (computer attached to the network) would be equal to all other nodes, with the ability to originate, pass, and receive messages. The path that a particu­lar message took in getting to its destination would be insignificant. Only the final result was important, as the message would be passed from node to node until it arrived at its destination.

The experiment was (to say the least) enormously successful. Known origi­nally as the ARPAnet (Advanced Research Projects Agency network),the original network of four computers has grown exponentially to include tens of millions of computers at virtually every major university and government agency, and an ever increasing number of private corporations and international sites. To say that the Internet is large is a gross understatement, but by its very nature, it's impossible to determine just how large it really is. How many networks there are, and how many users are connected to those networks, is of no importance as long as you yourself have access.

The Internet is a network of networks, but if that were all it were, there would hardly be so much commotion. It's what you can do on the Internet, cou­pled with the ease of access, that makes the Internet so exciting. In essence, the Internet provides two basic capabilities, information retrieval and worldwide com­munication, functions that are already provided by libraries and print media, the postal system and the telephone, television, and other types of long-distance media. The difference, however, is that the Internet is interactive in nature, and more importantly, it is both global and immediate.

TCP/IP

Data is transmitted from one computer to another across the Internet through a series of protocols known collectively as TCP/IP (Transmission Control Protocol/Internet Protocol). You can progress quite nicely through our text without knowing anything more about TCP/IP. We do, however, provide an appendix in case you are curious about the internal workings of the Internet.

The Internet enables you to request a document from virtually anywhere in the world, and to begin to receive that document almost instantly. No other medium lets you do that. Television, for example, has the capability to send infor­mation globally and in real time (while events are unfolding), but it is not inter­active in that you cannot request a specific program. Federal Express promises overnight delivery, but that is hardly immediate. The books in a library provide access to the information that is physically in that library, but that is not global access. Indeed, the Internet, and in particular, the World Wide Web is truly unique.