Transcript L2-410-F04 - Department of Computing Science

Web-Based Information
Systems
Fall 2004
CMPUT 410: Internet and WWW
Dr. Osmar R. Zaïane
University of Alberta
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
1
Course Content
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Introduction
Internet and WWW
Protocols
HTML and beyond
Animation & WWW
CGI & HTML Forms
Javascript
Databases & WWW
Dynamic Pages
 Dr. Osmar R. Zaïane, 2001-2004
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Perl & Cookies
SGML / XML
CORBA & SOAP
Web Services
Search Engines
Recommender Syst.
Web Mining
Security Issues
Selected Topics
Web-Based Information Systems
Preliminaries
University of Alberta
2
Objectives of Lecture 2
Internet and WWW
• Get a brief overview of the history of the
Internet and the different tools that exist on
the Internet;
• Understand the distinction between the
Internet and the World-Wide Web.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
3
Outline of Lecture 2
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The Memex machine: the dream will come true
Hypertext: linking new kinds of documents
The Internet: infallible information exchange
The World-Wide Web and the start of a new era
Web-based applications
Some terminology
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
4
When Did It All Start?
• In 1945, Vannevar Bush wrote an article “As
We May Think” describing a machine,
Memex, containing human collective
knowledge organized with “trails” linking
materials of the same topic.
• The article revolutionized information
technology before even the existence of
modern computers.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
5
Where is the memex?
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Memex is a hypothetical machine.
The information stored ought to be accessible.
We haven’t fulfilled the dream yet.
But much has been achieved in 50 years.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
6
Outline of Lecture 2
•
•
•
•
•
•
The Memex machine: the dream will come true
Hypertext: linking new kinds of documents
The Internet: infallible information exchange
The World-Wide Web and the start of a new era
Web-based applications
Some terminology
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
7
Hypertext-Hyperlink-Hypermedia
• Following Memex idea, Ted Nelson developed
the Xanadu project which aimed at placing the
entire world’s literary corpus on-line.
• Ted Nelson coined the term hypertext in 1965.
A document is not contiguous but is a set
of connected parts of documents.
Hyperlinks are links that connect subdocuments. Hypermedia is a multimedia
hypertext document,
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
8
Outline of Lecture 2
•
•
•
•
•
•
The Memex machine: the dream will come true
Hypertext: linking new kinds of documents
The Internet: infallible information exchange
The World-Wide Web and the start of a new era
Web-based applications
Some terminology
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
9
ARPAnet
• In the heart of the cold war, ARPA (Advanced Research Projects
Agency) was created (1957). The purpose was to outrun the
Russians in the race for mastering rocket launching.
• In 1969, it was decided to link sensitive computer centres by a
network in order to withstand a possible nuclear attack. The
idea was to allow centres to communicate even after a centre is
destroyed. (Bob Taylor’s idea)
• It connected government labs, major research centres and
universities.
• It existed until 1988 and was officially dismantled in 1990.
• Backbone Network speed: 64Kbits/second
• Major achievements:
– TCP/IP, Domain Name Service, e-mail (SMTP), FTP, Telnet...
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
10
NSFnet
• DARPA, the Defense Advanced Research Projects
Agency, still exists and the military have their own
network but the original ARPAnet was integrated into the
current Internet.
• The National Science Foundation in the USA funded the
NSFnet which was created in 1985.
• Backbone Network speed: T1 (1.5mb/sec.) to T3
(45mb/sec.)
• It originally connected 5 major universities with
supercomputer centres, but rapidly included other
universities, research centres and private companies.
• Replaced ARPAnet as the backbone of Internet in 1990
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
11
What about the Internet?
• The Internet didn’t originate in the USA alone.
• Other networks existed in North America and
Europe and other places in the world.
• BitNet, for instance, connected many research
centres and universities.
• Bridges connected these networks to create a
larger international network: the Internet.
• Late 90s: Internet2, funded by US universities,
a sequel to NSFnet with new protocols.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
12
CA net
Ca net
Ca net 2
Year
1990
1997
Ca net 3 1999
Speed USA equivalent
1.5 mb/s NSFnet
155 Mb/s Internet2
2.5 Gb/s Internet2
Abilene &
vBSN
projects
Canada committed $110 million for Ca net4,
a10 Gb/s optical network connecting research
institutions across Canada.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
13
Explosive
Growth
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
14
Internet Timeline
1970
1969
ARPANET
commissioned
by DoD
1980
1975
1974
1972
ARPANET
demonstration
1971
FTP on NCP
1973
First international
connection
(UK+Norway)
1
1969
4
1969
1982
ARPANET
transition to
1990
1986
NSF-Net
created
3
1973
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33
1989 1991
62
1974
 Dr. Osmar R. Zaïane, 2001-2004
2000
1995
1992
1994 1995 1996
1998
1990
Veronica
Harvest
Internet
Internet
Tax
ARPANET
Java
phone
Freedom
Act
ceases to exist
1993
1995
Mosaic
1997
1985
1988
1990
VRML
1999
TCP/IP
1981
1992
Wireless
FTP
IRC
Archie
Internet2
BITNET
MBONE
1994
Internet access
1986
NGI
and CSNET come
1991
E-commerce
NNTP
1998
1996
into being
Gopher
1993
Clever
1999
AltaVista
1983
Crawlers 1994
1991
RSVP
ARPANET splits
Yahoo
WAIS
1996
into ARPANET
1993
WebSQL
1998
1994
and MILNET
1992 W3C
Google
UCSTRI
WWW
1997
in CERN
1994
WebOQL
1991
1993
MLDB +
Netfind
Aliweb
WebQL
1979
USENET
TCP/IP
1985
213
1981
1,961
1985
313,000
1990
Web-Based Information Systems
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59 81
96
1992 1993 1994 1995
1,486,000
1993
134
171
1996 1997
6,642,000
1995
# countries
Year
36,739,000 # hosts
1998
Year
University of Alberta
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Outline of Lecture 2
•
•
•
•
•
•
The Memex machine: the dream will come true
Hypertext: linking new kinds of documents
The Internet: infallible information exchange
The World-Wide Web and the start of a new era
Web-based applications
Some terminology
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
16
Advent of the World-Wide Web
• In 1990, Tim Berners-Lee developed a on-line hypertextbased system to help researchers at CERN in Switzerland
share information across a diverse computer network.
• He came up with first versions of HTML (based on
SGML) and the HTTP protocol.
• HTTP and HTML catapulted the Internet to new heights.
• The WWW revolutionized the use of the Internet thanks
to a multimedia user friendly interface: a web browser.
• Mosaic was developed in NCSA by students at the
University of Illinois in 1993, among them Marc
Andreessen who created Netscape in 1995.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
17
The WWW is not alone
• There are other tools on the Internet. They
could be classified as:
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Command Line. Ex: FTP (1971)
Menu-based. Ex: gopher (1991)
Search engine. Ex: WAIS (1991)
Hypermedia. Ex: WWW (1991)
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
18
Other Taxonomy of Internet Tools
• Communication services
– E-mail, newsgroups (usenet), telnet, internet
relay chat (IRC), …
• Information storage and exchange
– FTP, Gopher, Alex, …
• Information Indexing
– Archie, Veronica, Wais, UCSTRI, Whois, …
• Interactive Multimedia information delivery
– WWW and its indexes.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
19
Outline of Lecture 2
•
•
•
•
•
•
The Memex machine: the dream will come true
Hypertext: linking new kinds of documents
The Internet: infallible information exchange
The World-Wide Web and the start of a new era
Web-based applications
Some terminology
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
20
Client-Server Architecture
The World-Wide Web is an
assortment of interconnected
computers. In this context,
computers provide data to
other computers.
Provides the
information
Requests the
information
Server
Client
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
21
Client-Server Architecture
Request
Client
HTTP
Response
 Dr. Osmar R. Zaïane, 2001-2004
URL
Web-Based Information Systems
Server
HTML page
University of Alberta
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Client-Server Architecture
Request + Data
HTTP
DB
Response
Browser
Javascript and
Java
 Dr. Osmar R. Zaïane, 2001-2004
HTTP server
Application
Web-Based Information Systems
CGI + Servlets
(Perl and Java)
University of Alberta
23
Application / Application
Communication – scenario 1
Application
Identifying
fields and
variables
Wrapper
needed
Application
Parses the
HTML page
to extract the
Wrapper needed
needed information
Request + Data
HTTP
DB
Response
HTTP server
No browser involved
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
24
Application / Application
Communication – scenario 2:
XML request + Data
XML
doc
SOAP over
HTTP
Web Service
Application
parses XML
with known
DTD or
schema
DB
Response
XML
doc
HTTP server
CORBA can also be used to exchange objects
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
25
Outline of Lecture 2
•
•
•
•
•
•
The Memex machine: the dream will come true
Hypertext: linking new kinds of documents
The Internet: infallible information exchange
The World-Wide Web and the start of a new era
Web-based applications
Some terminology
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
26
Terms in the Glossary
• Internet: group of networks connected together. The Internet refers to the
global connection of networks around the world.
• LAN: Local Area Network: a group of computers, usually all in the same
room or building, connected for the purpose of sharing files, exchanging
email, and collaboration.
• Intranet: internal company network. Internal use of web capabilities.
• Extranet: ability to securely connecting the intranet with defined
external networks.
• CGI: Common Gateway Interface: means of developing application for the
web on the server side.
• Middleware: a tier usually between a web application or a web server
and a database or another application layer.
 Dr. Osmar R. Zaïane, 2001-2004
Web-Based Information Systems
University of Alberta
27