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The WWW for eLearning
3.1 WWW Concepts
“The WWW principle of universal readership is that once information is available, it should be accessible from any
type of computer, in any country, and an (authorized) person should only have to use one simple program to
access it. ”
The World Wide Web
was developed in 1989 by Tim Berners-Lee
of the European Particle Physics Lab (CERN) in
Switzerland
NCSA Mosaic
was originally designed and programmed for X by Marc Andreessen and Eric Bina at NCSA.
Version1.0 was released in April, 1993.
Version 2.0 was released in December 1993, along with version 1.0 releases for both the
Apple Macintosh and Microsoft Windows
Tim Berners-Lee’s slides to introduce the WWW (1993)
Tim Berners-Lee
Tim Berners-Lee
“The WWW uses hypertext as the method of presentation... links can lead from all or part of a document to all or part of
another document.
Documents need not be text: they can be graphics, movies and sound, so the term hypermedia (multimedia hypertext)
applies equally well to the WWW.”
Tim Berners-Lee
“Whilst hypertext is a powerful tool for finding information, it cannot cope with large amorphous masses of data. For
these cases, computer-generated indexes allow the user to pick
out interesting items from textual input.”
“Whilst hypertext is a powerful tool for finding information, it cannot cope with large amorphous masses of data. For
these cases, computer-generated indexes allow the user to pick
out interesting items from textual input. There are therefore two operations a reader can use: the hypertext jump and
the text search.”
Tim Berners-Lee
“The web ... was designed without any centralized facility... There is no central control.
To publish data you run a server, and to read data you run a client.”
Tim Berners-Lee
“A feature of HTTP is that the client sends a list of the representations it understands along with its request, and
the server can then ensure that it replies in a suitable way.”
Internet protocolsSets of rules that allow for inter-machine communication
on the Internet.
E-mail (Simple Mail Transport Protocol or SMTP) Telnet (Telnet Protocol)
FTP (File Transfer Protocol) Usenet (Network News Transfer Protocol or NNTP)
HTTP (HyperText Transfer Protocol)
Anatomy of a URL
For example, the URL of the home page of the House Committee on Agriculture of the U.S.A. House of Representatives:
http://www.house.gov/agriculture/schedule.htm
1.Protocol: http 2.Host computer name: www 3.Second-level domain name: house 4.Top-level domain name: gov 5.Directory name: agriculture 6.File name: schedule.htm
Domain name examples
.com commercial enterprise .edu educational institution .gov U.S. government entity .mil U.S. military entity .net network access provider .org usually non-profit organizations
Languages
CGI JAVA
VRML XML
Languages
CGIprograms for data that conforms to the CGI specificationJAVA
VRML XML
Languages
CGIprograms for data that conforms to the CGI specificationJAVA"Write once, run anywhere.”VRML XML
Languages
CGIprograms for data that conforms to the CGI specificationJAVA"Write once, run anywhere.”VRMLfor the creation of three-dimensional worldsXML
Languages
CGIprograms for data that conforms to the CGI specificationJAVA"Write once, run anywhere.”VRMLfor the creation of three-dimensional worldsXML“to separate form from content”
A method for graphical input on the WWW
Lesley Parks & Ernest Edmonds
The objects were constructed from a combination of graphics primitives (lines,
circles, ellipses, boxes) with semantic information (constraints & textual descriptions). The data defining such an object was capable of being stored in and retrieved from a knowledge base accessible from a Web server. The results
of the user's interaction with the object was to be returned to the server.
Knowledge Server
Browser
Knowledge Server
Browser
Knowledge Server
Browser(face,x,y,z)
Good design
Animation and fun
Superbad.com
“There is no reason why anyone would want to have a computer in their home”
Ken Olson, President of DEC, 1977
Study these links provided from the web site
Laura Cohen: Understanding the World Wide Web
World Wide Web Consortium