WebBased Information Systems 2 : WWW and Web Browsers

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Web-Based Information Systems (2) WWW and Web
Browsers
Prof. Man-Gon Park Division of IT
Comm. Colombo Plan Staff College
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CONTENTS
2. World Wide Web(WWW) 2.1 Brief History
2.2 Internet Role Players 2.3 WWW
Middle-ware 2.4 Web Site
3. WWW Browsers 3.1 Web Browsers on History
3.2 Browser wars 3.3 Netscape Navigator
4.0 3.4 Microsoft Internet Explorer 3.5
How to access a Web Site 3.6 How can you
search the information on the Web
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2. World Wide Web(WWW)
2.1 Brief History
? World Wide Web (WWW) is a wide-area
information-retrieval project which was started
in 1989 by Tim Berners-Lee at the Geneva European
Laboratory for Particle Physics (known as CERN,
based on the laboratorys French name).
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? The initial proposal suggested development of a
hypertext system to enable efficient and easy
information sharing among geographically
separated teams of researchers in the high-energy
physics community.
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? By the end of 1990, a line browser (called www)
had been developed which implemented the
principles of hypertext access and the reading of
different document types.
? In 1991, the line browser was made available to
the CERN community, and a gateway for Wide Area
Information Servers (WAIS) searches was developed.
? In 1992, a few more browsers were developed and
around 50 Web sites (the machines which house Web
documents) were implemented.
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? In 1993, an extremely important event took
place, i.e., the Mosaic browser for GUI access
was developed at NCSA (National Center for
Supercomputing Applications at University of
Illinois). Ignited by the ease of use provided
by the Mosaic GUI browser, the Web took off
during 1993the number of Web sites increased to
500, and the Web network traffic grew from 0.1
of Internet traffic to 1 .
? Since 1994, the Web has been gaining popularity
dramatically, with astounding increases in the
number of browsers, search engines, Web servers,
and usage.
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2.2 Internet Role Players
? Internet users are the people who visit the
shopping mall (i.e., log on to the Internet).
The Internet users are essentially the consumers
of the services provided by the Internet.
? Content providers are the merchants
(individuals, groups, or organizations) that
provide the products in the shopping mall (i.e.,
resources available on the Internet). You can
think of these content providers as the merchants
in the shopping mall.
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? Internet access providers (IAPs) are the
organizations that facilitate your access to the
shopping mall (i.e., give you a communication
line and an access port on the Internet). You
can think of IAPs as the local authorities that
provide you with roads and signs to get you to
the shopping malls
? Interne service providers (ISPs) are the
individuals and organizations that help the
content providers set up their shops in the
shopping mall (i.e., help in building Web sites).
Many small content providers seek the help of
ISPs to set up Web servers with appropriate
security and backup/recovery.
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2.3 World Wide Web Middle-ware
? Technically speaking, WWW is a collection of
middle-ware that operates on top of TCP/IP
networks (i.e., the Internet). ltFigure 2gt
shows this layered view.
? The purpose of the WWW middle-ware is to
support the growing number of users and
applications ranging from entertainment to
corporate information systems.
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World Wide Web Applications
World Wide Web Middle-ware (Web browsers, Web
servers, HTTP, HTML, Web Gateways)

• TCP/IP Network Stack
• FTP, Telnet, SMTP, Sockets
• TCP, UDP
• IP

ltFigure 2gt Technical View of WWW
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• ? WWW middle-ware is bases on a few simple
  concepts and technologies such as the following
• Web servers and sites
• Web browsers
• Uniform Resource Locator (URL)
• Hypertext Transfer Protocol (HTTP)
• Hypertext Markup Language (HTML)
• Web navigation and search tools
• Gateways to non-Web resources

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2.4 Web Site

• ? Conceptually, a Web site is a catalog of
• information for each content provider over the
• Web.
• ? In reality, a Web site consists of three types
  of components
• a Web server (a program),
• content files (Web pages),
• and/or gateways (programs that access
• non-Web content).

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UNIX Mackintosh
PC
Web Browser (X Mosaic)
Web Browser (Microsoft)
Web Browser (Netscape)
HTTP
HTTP
URL http//unicorn.pknu.ac.kr/mpark/
HTTP
HTTP
Web Search Tools

• Web Site www.shoe.com
• Web server (program
• HTML Documents
• Gateway for DB Access

• Web Site unicorn.pknu.ac.kr
• Web server (program)
• HTML Documents
• (Faculty.html, courses.html)

Databases
ltFigure 3gt Conceptual View of World Wide Web
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3. Web browsers
3.1 Web browsers on History
? Web browsers are the clients that typically use
graphical user interfaces(GUI) to wander through
the Web sites.
? The first GUI browser, Mosaic, was developed at
the NCSA at the University of Illinois. Mosaic
runs on PC Windows, Macintosh, UNIX, and
X-terminals.
? At present, Web browsers are commercially
available from Netscape, Microsoft, and any other
software/freeware providers.
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Uniform Resource Locator (URL)

• ? URL is the basis for locating resources in WWW.
  A example of URL (the Home page of Dr. Man-Gon
  Park)
• http//unicorn.pknu.ac.kr/mpark/en_welcome.html/
• The http in the URL tells the server.
• The unicorn.pknu.ac.kr is the name of the
  machine running the Web server.
• The mpark/en_welcome.html is the name of a
  file on the machine unicorn.pknu.ac.kr.

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The general format of URL
? protocol//hostport/path
protocol represents the protocol to retrieve or
send information. Examples of valid protocols
are HTTP, FTP, Telnet, Gopher, and NNTP (Network
News Transfer Protocol).
host is the computer host on which the resource
resides.
port is an optional port number (this is not
needed unless you want to override the HTTP
default port, port 80).
path is an identification, typically a file name,
on the computer host.
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Two Ways to Access a Browser
? A Web Browser is a program that lets you view
and explore information on the WWW.
? There are two ways to access a Browser.
? The first and preferred way is to have one
installed on the computer you use to access the
Internet.
? The second way is to telnet to another computer
on the Internet that offers public access to its
Browser.
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3.2 Browser Wars
? There are now at least a dozen different Web
Browsers available for a given computer platform,
including software distributed by Netscape,
America Online, Prodigy, Spyglass, PSINet,
Netcom, Microsoft, and others.
? All of these Browsers have their own specific
sets of capabilities and features. Most of them
will display Web pages designed to conform to the
HTML standard.
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3.3 Netscape Navigator 4.0
? Netscape Navigator 4 is currently the most
popular Web Browser used to view Web pages.
Netscape Navigator 4 is available for computers
running many different operating systems,
including OS/2, Mackintosh, Windows and Unix.
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• ? Netscape Communicator 4 is a tightly integrated
  software suite including 4 main components and 5
  auxiliary components as follows.
• Navigator 4 (Web Browser)
• Messenger (E-mail)
• Collabra (Discussion groups)
• Composer (Web pages creation)
• Netcaster (Web channels)
• Host-on-Demand
• Autoadmin
• Conference (Real-time collaboration)
• Calendar

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ltFigure 4gt The Communicator 4 menu in Navigator
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3.4 Microsoft Internet Explorer
? Microsoft Internet Explorer is a newer Web
Browser that is quickly becoming one of the most
popular Web Browsers.
? Internet Explorer was created by the same
company that created the Windows operating
systems. This means that the look and feel of
Internet Explorer is similar to the look and feel
of other Microsoft software systems.
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ltFigure 5gt The Internet Explorer menu with the
Microsoft home page
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3.5 How to Access a Web Site
If you want to open a specific Web site of which
you already know the URL (Web address, example
http//www.louvre.fr)
? Double-click now on the Browser, Netscape
Navigator 4.
? On the Location, type the Web site address,
http//www.louvre.fr, and press ENTER key.
? Then the Home page of Louvre Museum in
Paris appears.
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? In order to open the following pages, simply
position your cursor on the underlined words,
watch the arrow transform itself into a hand and
click on your mouse.
? If you want to use the Bookmarks facility for
fast and easy access to your favorite webpages
without retyping of the address, you can add the
current page to the bookmarks menu.
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ltFigure 6gt Home page of Louvre Museum in Paris
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3.6 How can you search the information on the Web
? There are two methods you can search Web sites
using either inventories or search engines both
are closely related but present themselves
differently.
? An inventory provides you with a structured
index of all subjects on which you can find
information on the Web. This index is arranged by
topics and sub-topics.
? A search engine is a tool which allows you to
search all Web pages by any word or combination
of words of your choice.
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ltFigure 7gt Home page of inventory Yahoo
(http//www.yahoo.com)
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ltFigure 8gt Home page of search engine Alta Vista
(http//altavista.digital.com)
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