What is the Internet?
Internet is a network of
networks. It is a single switch that allows machines to alternatively be
clients or servers or peers to communicate with one another. Based on a
set of protocols know as the TCP/IP protocol suit, the Internet uses a
system of packet switching for data transfer. Growing from research originally
funded by the U.S. Advanced Research Projects Agency in the late 1960s
and early 1970s, the Internet was designed to be highly robust in case
one section of the network (or a computer host in the network) became inoperable:
Packets could simply be transmitted over another route through the network,
because no one network path was essential.
What is The World Wide Web?
The WWW is a very distinct
system from the Internet. The WWW is not a network, but an application
system (a set of woftware programs). The WWW can be deployed and used on
many different kinds of networks or it could even be used on no network
at all.
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The WWW is a hypertext information
and communication system used on the Internet computer network with data
communications operating according to a client/server model. Web clients
(browsers) can access multiprotocol and hypermedia information (where helper
applications are available for the browser) using an addressing scheme.
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The WWW is made of hypertext.
The Web's hypertext is written using Hypertext Markup Language (HTML),
an application of Standard Generalized Markup Language (SGML). SGML
is an international standard (ISO 8879) for text information processing.
HTML is defined by SGML and is intended as a semantic markup language,
demarcating the structure of a document rather than its appearance.
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In mathematical terms, the WWW
is a directed graph, in which nodes (the Web's hypertext pages) are connected
by edges (the Web's hypertext links).
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The WWW is an information and
communication system. The Web allows both information dissemination and
information collecting.
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The WWW uses data communications
operating according to a client-server model. A client-server model for
networked computer systems involves three components: the client, the server
and the network. A client is a software application that most often runs
on the end user's computer host. A server is a software application that
most often runs on the information provider's computer host. Clients and
servers are connected called networks.
History of WWW
- Vannevar Bush described
a system for associatively linking information in his article in The
Atlantic Monthly, "As
We May Think" - July 1945.
- In 1965, Ted Nelson coined
the term hypertext to describe text that is not constrained to be
sequential. Hypertext, as described by Nelson, links documents to form
a web of relationships that draws on the possibilities for extending and
augmenting the meaning of a "flat" piece of text with links to other texts.
He also coined the hypermedia, which is hypertext not constrained
to be text. Hypertext can include multimedia - pictures, graphics, sound,
and movies.
- In March 1989, Tim Berners-Lee,
a researcher at the Conseil Europeen pour la Recherche Nucleaire (CERN)
European Laboratory for Particle Physics in Geneva, Switzerland, proposed
a hypertext system to enable efficient information sharing for members
time software, and communications, and had previously developed a hepertext
sytem that he called Enquire in 1980.
- By late 1990, an operating
prototype of the WWW ran on a NeXT computer, and a line-mode user interface
(called www) was completed. The essential pieces of the Web were
in place, although no widely available for network use.
- In March 1991, the www
interface was used on a network, and by May of that year it was made available
on central CERN machines. CERN annouced the availability of the files in
the Usenet newsgroup alt.hypertext on August 1991. In October 1991,
a gateway from the Web to Wide-Area Information Server (WAIS) software
was completed.
- During 1992, the Web continued
to develop, and interest in it grew. On January 15th, the www interface
became publicly available from CERN.
- In February 1993, Mosaic
was released. Mosaic is a browser for the Web ran on X Window System developed
by a team in National Center for Supercomputing Applications led by a young
undergraduate at the University of Illinois at Urbana-Champaign named Marc
Andreessen.
- (to be continue)