What are WWW, hypertext and hypermedia?
WWW stands for "World Wide Web." The WWW project, started by Tim Berners-Lee while at CERN (the European Laboratory for Particle Physics), seeks to build a "distributed hypermedia system." In practice, the web is a vast collection of interconnected documents, spanning the world. Tim Berners-Lee continues his pioneering work with the W3 Consortium at MIT.
The advantage of hypertext is that in a hypertext document, if you want more information about a particular subject mentioned, you can usually "just click on it" to read further detail. In fact, documents can be and often are linked to other documents by completely different authors -- much like footnoting, but you can get the referenced document instantly!
To access the web, you run a browser program. The browser reads documents, and can fetch documents from other sources. Information providers set up hypermedia servers which browsers can get documents from.
The browsers can, in addition, access files by FTP, NNTP (the Internet news protocol), gopher and an ever-increasing range of other methods. On top of these, if the server has search capabilities, the browsers will permit searches of documents and databases.
The documents that the browsers display are hypertext documents. Hypertext is text with pointers to other text. The browsers let you deal with the pointers in a transparent way -- select the pointer, and you are presented with the text that is pointed to.
Hypermedia is a superset of hypertext -- it is any medium with pointers to other media. This means that browsers might not display a text file, but might display images or sound or animations.
You have two basic options: use a browser on your own machine (the best option) or use a browser that can be telnetted to (not nearly as good, but possible). Web access by email is available, but very marginal. Note, however, that the traditional online services such as AOL, Prodigy, and Compuserve now offer web access of one degree or another as a standard feature. Real web access is finally easy to come by for all PC users, at least in North America.
It is always best to run a browser on your own machine, unless you absolutely cannot do so; but feel free to telnet to a browser for your first look at the web, or use email if the telnet command does not work on your system (try it first!). Note that "your machine" can be defined as a system you dial into from home, such as netcom or another account provider. Running a text-based browser on such a system is still preferable to telnetting to a faraway site.
Access to the web by email is possible once again, but obtaining a better grade of Internet access that allows you to run a web browser is strongly encouraged. To use the service, send mail to webmail@curia.ucc.ie with "go http://www.boutell.com/faq/" in the body of your mail (don't type the quotation marks). You will receive the top page of the web version of this FAQ, which you can use as a starting point for your explorations.
What are SGML and HTML?
Documents on the World Wide Web are written in a simple "markup language" called HTML, which stands for Hypertext Markup Language SGML is a much broader language which is used to define particular markup languages for particular purposes. HTML is just a specific application of SGML. You can learn more about SGML, and the rationale behind HTML, by reading A Gentle Introduction to SGML (URL is http://etext.virginia.edu/bin/tei-tocs?div=DIV1&id=SG), document provided by the Text Encoding Initiative.
How does WWW compare to GOPHER and WAIS?
While all three of these information presentation systems are client-server based, they differ in terms of their model of data. In gopher, data is either a menu, a document, an index or a telnet connection. In WAIS, everything is an index and everything that is returned from the index is a document. In WWW, everything is a (possibly) hypertext document which may be searchable.
In practice, this means that WWW can represent the gopher (a menu is a list of links, a gopher document is a hypertext document without links, searches are the same, telnet sessions are the same) and WAIS (a WAIS index is a searchable page, returning a document with no links) data models as well as providing extra functionality.
World Wide Web usage grew far beyond Gopher usage in the last few months, according to the statistics-keepers of the Internet backbone. (Of course, World Wide Web browsers can also access Gopher servers, which inflates the numbers for the latter.) WWW has long since reached critical mass, with new commercial and noncommercial sites appearing daily.
VRML, the Virtual Reality Modeling Language, is an attempt to extend the web into the domain of three-dimensional graphics. VRML "worlds" can depict realistic or otherworldly places, which can contain objects that link to other documents or VRML worlds on the web.
For more information about VRML, including where to find browsers and other VRML tools for your system, consult the VRML Home Page at Wired (URL is http://vrml.wired.com/) for general technical information about the effort, and the WebSpace home page at SGI (URL is http://www.sgi.com/Products/WebFORCE/WebSpace for the first VRML viewer to become available. You may also wish to check out the home page of VRWeb <URL:http://hgiicm.tu-graz.ac.at/Cvrweb>, another VRML browser available for Microsoft Windows and the X Window System.
Java is a language developed by Sun Microsystems which allows World Wide Web pages to contain code that is executed on the browser. Because Java is based on a single "virtual machine" that all implementations of Java emulate, it is possible for Java programs to run on any system which has a version of Java. It is also possible for the "virtual machine" emulator to make sure that Java programs downloaded through the web do not attempt to do unauthorized things.
Actually, Java can be used in the absence of the web, but the application that has sparked so much interest in Java is HotJava, a web browser written in the Java language. You can learn more about Java and HotJava from Sun's HotJava home page (URL is http://java.sun.com/).