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Overview of the WWWThis is a historical document and will be updated as time permits.
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. WHAT IS A URL?URL stands for "Uniform Resource Locator". It is a draft standard for specifying an object on the Internet, such as a file or newsgroup. URLs look like this: (file: and ftp: URLs are synonymous.)
The first part of the URL, before the colon, specifies the access method. The part of the URL after the colon is interpreted specific to the access method. In general, two slashes after the colon indicate a machine name (machine:port is also valid). When you are told to "check out this URL", what to do next depends on your browser; please check the help for your particular browser. For the line-mode browser at CERN, which you will quite possibly use first via telnet, the command to try a URL is "GO URL" (substitute the actual URL of course). In Lynx you just select the "GO" link on the first page you see; in graphical browsers, there's usually an "Open URL" option in the menus. 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 URL:http://etext.virginia.edu/bin/tei-tocs?div=DIV1&id=SG ), a 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. WHAT IS THE W3 CONSORTIUM?The W3 consortium is an industry consortium headed by the Laboratory for Computer Science at the Massachusetts Institute of Technology. The W3 consortium seeks to promote standards and encourage interoperability between WWW products. See [URL:http://www.w3.org] for more information. INTRODUCTION: HOW CAN I ACCESS THE WEB?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 e-mail 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 e-mail 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 e-mail_ 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/" iin 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. There is one low-tech solution: web by FAX! Consider the following information, submitted by Bill Stearns: If you have access to a fax machine, do the following:
A few other useful pages: 17581 800 number (toll-free) service providers, 17582 The list of area codes - a good place to start as well if you're in the U.S. By the way, this free service is provided by Universal Access (http://www.ua.com/, document number 16968) and is not limited to just this directory. If you know the name of the machine hosting the web page you want to view, you can probably reach it through this service. You simply type in the name of the machine (www.teleport.com, for example) at menu option 3. When you've received the home page for the site, keep following the trail to the page you'd like. It takes a while and some long distance calls, but the service is otherwise free. My sincere thanks both to Universal Access and the Celestin company for providing these services. WHAT IS ON THE WEB?By now, the Web is becoming a mainstream publishing medium in its own right. As such, virtually everything is available somewhere on the Web. Because it is cheaper to publish on the web than it is to publish on paper or in the other electronic media, a wide range of interests are represented. This is limited only by the fact that the population of the Internet is not yet as diverse as the population of the real world. Fortunately, that is changing as web access becomes more and more readily available. The real question is more often "how do I search the Web to find what I want?" or perhaps "where is the card catalog of the Web?". Those questions are also answered in this document. HOW DO I FIND OUT WHAT'S NEW ON THE WEB?comp.infosystems.www.announce
What's New With NCSA Mosaic
comp.internet.net-happinings
WHERE IS THE SUBJECT CATALOG OF THE WEB?There are several. There is no mechanism inherent in the web which forces the creation of a single catalog (although there is work underway on automatic mechanisms to catalog web sites). Also be sure to check out the entry on how to search the web. Yahoo is probably the most complete hierarchical, topical index of web sites, and also features a sophisticated search facility. The original catalog of the web was the WWW Virtual Library (URL is http://www.w3.org/hypertext/DataSources/bySubject/Overview.html ), maintained by CERN and later by the W3 Consortium. The Virtual Library is a good place to find resources on a particular subject, and has separate maintainers for many subject areas. HOW CAN I SEARCH THROUGH ALL WEB SITES?Several people have written robots which create indexes of web sites -- including sites which have not arranged to be mentioned in the newspapers and catalogs above. (Before writing your own robot, please read the entry in the authoring section regarding robots.) Here are a few such automatic indexes you can search:
You can read about other search robots and the principles behind them in the robots section. CAN I CATCH A VIRUS BY LOOKING AT A WEB PAGE?No. Your computer can, of course, catch a virus if you download an executable program from an untrustworthy site and then, of your own free will, double-click on it in your file manager (or Mac desktop, or...). This is the same risk you run when downloading programs from bulletin board systems or via anonymous FTP. Viewing images, filling out forms and so on is harmless. So, most likely, is downloading a program from a respectable source with a reputation to protect. HOW CAN I FIND OUT IF A WEB PAGE HAS BEEN UPDATED?Most of the time, web servers deliver information only when you ask for it. Usually this is a good thing, but in some cases you may want to be notified when a web page has changed. When you want notification that a page has changed, consider using URL-minder (URL is [http://www.netmind.com/URL-minder/URL-minder.html ] ), a web-browsing robot which will automatically notify you by e-mail when a page of interest to you has been updated. HOW CAN I PROVIDE INFORMATION TO THE WEB?Information providers run programs that the browsers can obtain hypertext from. These programs can either be WWW servers that understand the HyperText Transfer Protocol HTTP (best if you are creating your information database from scratch), "gateway" programs that convert an existing information format to hypertext, or a non-HTTP server that WWW browsers can access -- anonymous FTP or gopher, for example. To learn more about World Wide Web servers, see the server section. You can also consult a www server primer by Nathan Torkington, available at the URL http://www.vuw.ac.nz/who/Nathan.Torkington/ideas/www-servers.html. If you only want to provide information to local users, placing your information in local files is also an option. This means, however, that there can be no off-machine access. WHO USES THE WEB?Good question! The web is certainly biased toward the thirtyish, anglo-saxon, male and technology-friendly crowd at this point, but there's more to the story; the demographics of the web are changing rapidly as the user base grows. The GVU WWW User Survey (URL is [URL:http://www.cc.gatech.edu/gvu/user_surveys/User_Survey_Home.html]) attempts to answer the question in detail. You can access the results of past surveys and contribute information of your own. WHAT IS VRML?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 [URL:http://vrml.wired.com/] ) for general technical information about the effort, and the WebSpace home page at SGI (URL is [URL: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. WHAT IS JAVA?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 [URL:http://java.sun.com/] ). WHAT CAN I DO TO PROTECT MY LEGAL RIGHTS ON THE WEB?This question is analyzed in admirable detail by the Weblaw Page [URL:www.patents.com/weblaw.sht]. Disclaimer: Neither that page nor this FAQ constitutes legal advice. |