The World Wide Web

The Worldwide Web (often abbreviated to WWW and mostly just called The Web) is an enormous worldwide network of hypermedia documents that contain information in the form of text, pictures, and, in some cases, video clips and sound. One calls a document a hypertext document if it contains text and "links" to other documents filled with information. A document is called a hypermedia document when it not only contains text but also pictures, sound, or video clips that themselves link to other documents. Typically, these links are located anywhere in the document and are indicated by highlighted and/or underlined words that may be clicked on with the mouse to activate the linked document. These hypermedia documents reside on servers located all over the world called "Web Servers". There are literally thousands of these servers spread throughout the world. The beauty of the WWW is that you can retrieve these documents from all over the world without knowing the composition of the document or on what server the documents are physically located. A typical session on the Internet may take you from East Coast to West Coast in the United States, or to Europe, Asia, or Australia all within a few seconds. The Internet is not only used as a vehicle for the transport of the information, but also as a way to access other the resources available on the Internet; for example, Gopher, Telnet, FTP, and Usenet.

The idea of the Web was originally conceived and developed in Switzerland by a group of physicists at the CERN research center. Their goal was to develop a means to share their work with other researchers using hypermedia documents. This idea quickly expanded and is now accepted as the preferred method of accessing information on the Internet.

Hypermedia documents can be read with the help of a computer program called a Web browser (or viewer). Although command line browsers are available, browsers that operate in the full-screen graphics mode are the most popular. One of the most popular full-screen browsers are Mosaic and Netscape, but other are becoming rapidly available. When you first start a browser you are automatically connected to a hypermedia document serving as your starting point, which is referred to as your Home Page. An example is given in Figure 4, the home page of the Department of Anesthesiology. From this home page you can go to other documents, bring up pictures, or "Surf the Web" by clicking with the mouse on the highlighted linking elements. The browser must activate required viewers that allow you to look at the graphics or video clips, play a sound track, or activate a Telnet or Gopher session.

One popular Web browsers is NCSA Mosaic (Mosaic). Mosaic is a computer program (software) developed by the Software Development Group (SDG) at the National Center for Supercomputing Applications (NCSA) in Urbana-Champaign IL (UIUC) and is available for free to anyone. There are versions available for PCs running Windows, MacIntoshes, and all sorts of other workstations. Mosaic is more than just a Web browser; it opens the door to most of the major server types on the Internet: HTTP servers (the standard server on the Web), FTP servers, Gopher servers, and WAIS servers. With this capability, you can access files on virtually any of the major servers on the Internet.

Currently, the most popular and powerful browser is Netscape from Netscape Communication Company. There are versions available for PC's running Windows, MacIntoshs, and all sorts of other workstations. For the PC users either Netscape or Mosaic will suit your needs and selecting one will depend on persoanl preferences. Because of the built-in capabilities, we recommend the use of Netscape.

A number of very well written on-line WEB sites offer additional information on how to use the browsers, HTML, the Hypertext Markup Language used to program the WEB pages, and about Telnet, TCP/IP, FTP and MUCH MUCH more.

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