Ø World Wide Web – World Wide Web is a huge collection of Hyper
Text pages on the internet. The concept of World Wide Web was developed in the year of 1989 by Switzerland’s company CERN. The firs text
based proto type was operational in 1991. IN the year of 1993 the first
graphical interface software package called MOSAIC. MOSAIC was released to
access the web server you use client software called a web browser.
Ø
Basic features of world wide
web-
1.
Hypertext information system- the idea behind hyper text
is that instead of reading text in a rigid leanes structure you can skip easily
from one point to another. You
can get more information, go back, and jump to other topics in the World Wide
Web.
2.
Graphical and easy to
Navigate-
one of the best features of the World Wide Web is its ability to display both
text and graphics in full color on the same page.
3.
Cross platform – if you can access the
internet you can access the World Wide Web also. Cross platform means that you
can access web if information equally well from any computer hardware running
any operation system.
4.
The web is distributed- the web is successful in
providing so much information is distributed globally across thousands of websites,
each of which contributes the space for the information it publishes.
5.
The web is dynamic- because information on the
web is contained on the site that published it; the people who published it in
the 1st place can update it at any time.
6.
Accessing many forms of
internet information – to use browser to get different type of information on the internet,
you can use different kind of URL’s most URL’s starts with http and indicates a
file at an actual website.
7.
The web is interactive – interacting is the ability to take back to the
web server. Unlike television the web is interactive
Ø
World Wide Web Browsers – A web browser is a
programme you used to view pages and navigate the World Wide Web.
A
wide range of web browser is available for every type of system. There are
following list of popular web browsers.
1.
Mosaic- mosaic few years ago
mosaic was the 1st full color graphical web browser and is the
instrumental in making the web as popular as it is today. Mosaic was developed
by NCSA, at the University of ILLINIOUS with several supported commercial
versions.
2.
LYNX-lynx is the idle solution
for people who don’t want to take time to use the web graphically. It is fast
and it enables you to get hold of just about everything on the web.
3.
Netscape navigator – Netscape navigator known
as Netscape is available for windows and for many different versions of UNIX
operation system.
Ø World Wide Web Servers – to make available the services of web pages
website need a host (a computer) and server software that runs of on the hosts.
The host manages the communication Protocol and the related software requires
creating a website on the internet. The server software resides on the hosts
and server up to pages and acts on the requests send from the client browser
software. A web server is kind of program that runs on a website and is
responsible for replaying to web browser requests.
Ø Types of servers- there are different types of server software for example database
server, or network server, etc, that perform different types of services for
different type of clients. A web server is an HTTP server and its function
to send information to the client software using the Hyper Text Transfer
Protocol.
Ø
Function performed by the
Web Server-
a web server perform following jobs
1.
It passes requests to run common gateway interface script to the common
gateway interface application.
2.
The server software includes configuration files and utilities to
secure and mange the websites.
Ø
HTTP Hyper Text Transfer
Protocol-
HTTP protocol is used mange the links between one hyper text document and
another. HTTP is the mechanism that opens the documents when you select a hyper
text link no matter where that document resides on the web. Web document are
marked for formatting and linking with HTML, and web servers use http to
deliver that web pages to the client.
Ø
URL Uniform Resource Locator – URL’s contains
information about both the access method to use and also about the resource
itself. They are used by web browsers to connect you directly to a specific
document or page on the World Wide Web for example http://www.google.com http://www.nielit.gov.in
Ø
Search engines – we can think that the web
search is information searched on the internet. A search engines is software
that searches through a database of web pages for specific information.
Ø
Category of Search Engine /
Different types of search engines- there are many search engines available on the web
most of the search engines provide web site reviews and home page services in
addition to key work search. There are following types of search engines.
1.
Yahoo- it is basically a search
directory. It is hierarchically organized with subject catalogue of directory
of the web pages which are browser able and searchable. Links to various
services are accomplished in two ways
1.
By user’s submissions
2.
Through robots that retrieve new links from known pages.
2.
ALTA-VISTA- this has created by the
search facilities of digital electronic corporation (DES) of U.S.A. This search
engine has a spider called scooter that traverses the web. ALTA-VISTA does not
offer any news or hot site nor does it provide or any categories information.
3. HOT-BOT- this search engine retrieves an indexes web document using a robot
called SLURP and a parallel network of work stations. The HOT-BOT search engine
contains a text box for the users to enter their query string and this box to
choose the appropriates rules.
4. EXCITE-
excite search engine uses a spider and index for the full text search of
document. This engine is a full featured search engine. It offers services like
searches that are case sensitive. The bowline operator used by excite and or.
5. INFOSEEK – INFOSEEK in a popular search engine with a robot that retrieves html
and PDF documents. It indexes full text and generate a short summary of each
document. This offers indexed site searches and divides the web into number of
convenient baskets.
6. LYCOS-
this search engine contains 66 millions pages in its database. This search
engine has a robot to navigate the web and build a searchable index. It also
offers a lot of contain like news, site review, links a particular document
etc. It also has the ability to search for images and sounds.
How to
search using search engine – using a search engine is very simple. Just
type data that you want to search on the space provided by search engines
current page and click on search. The result will be displayed with information
corresponding to the search in the form of clickable URL’s loading to the pages
you seek
Terminology used for search
on the web
1. Hyper text- a hyper text is a system of organizing, navigating, distributing and publishing
information is organized into an interconnected web of linked text and images.
Hyper text document’s called web pages that allow you to navigate to another
part of the same document. It is also used for accessing information on the
internet. Hyper text makes extremely large volume of information from wide
variety of sources available on the web page. The most common example of the
hyper text is the help system available in window and other window based
application like M.S. Excel, MS Word.
2. Hyper links- a hyper link on link is a navigational element in a hyper text
document which provides access to another hyper text document. That you may
wish to visit web browsers distinguish text hyper links by blue color or
underline text block. When clicked with a mouse a hyper link download and
displays.
There is no limit to the number of hyper links that
can be placed in a web page. Hyper links often direct you to related or more
detailed information requiring to the desired subject.
Linear and non- linear
information- linear information is a information in book or magazine which is
intended to be understood in a specific predefined order. If information is
distributed that information is called non- linear information.
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