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The Internet
• Facilitates Global data
• A Global computer network
• Links millions of people and
computers worldwide
• Is made up of thousands of LANs
and WANs and individual computer
users with network connections
Internet Terms
Internet v WWW
Web Browser
Web Server
IP address
Website v Home Page
URL v Domain name
Internet & WWW
• The Internet is the physical
structure of computers, cables,
satellites and other hardware and
software that creates the link
• The WWW is the browser, the
hyperlinks and the websites that
allow users to navigate the global
network and communicate
Web Browser
• The software that facilitates
navigation (surfing!)
• It is the user interface on
– Mosaic, Netscape Navigator and
Internet Explorer
• Uses hyperlinks to jump from page
to page (to navigate)
Web Server
• A large computer with huge storage
capacity that stores websites
• It delivers information and files to
users computers as and when
• There are many web servers on the
Website and Home Page
• A website
– is a collection of files uploaded to a web
server and concerning a particular
organisation, individual or government
agency etc
• A Home Page
– is the first page you meet in a website –
the introductory page
IP Address
• Each connection to the internet is
identified by its IP Address
• This is a number which is allocated to
the connection by the ISP
– such as “234,208.12.129”
• Since these are not intuitive many
sites use domain names for
URL and Domain Name
• A URL (Uniform Resource Locator) is
the address of a particular website or
of a particular file (page) in a website
• A domain name is part of a URL
– Domain names are purchased to make a
site address easier to remember
– Domain names are fixed while IP
addresses are not
• The URL has 3 parts
– http://www (the protocol)
– (the domain name)
– index.html (the actual file in the
website being looked for)
• A protocol is a set of rules for the
exchange of data between
– Responsible for routing the data
– Responsible for ensuring that data is
not corrupted or lost in transmission
– Looks after the sending and receiving
of messages
Some Protocols
File Transfer (FTP)
• Using FTP (File Transfer Protocol) a
user can download a file from a web
server to his/her own hard drive
– Music, software etc can be downloaded in
this way
– Can save a web page to your hard drive so
there is no need to visit the website to
view the page again
• The protocol used to transfer
files from the web server to
the user’s computer screen
• This is a protocol that is used
so that emails can be sent over
the internet
• Used on websites, it allows web
surfers to send an email to the
site they are visiting
What is the Internet
Used for?
File Transfer/Download
Buying/Selling - Ecommerce
Chat Rooms
• The most used service of the Internet
– Can send messages 24/7
– Cheap – the cost of a local call
– Can send messages to groups for cost of
one – saves money on postage/time etc
– Crosses time barriers – facilitates global
– Can attach files to your email ie photos,
word documents, spreadsheet files etc
• Groups of people with similar
interests can share information
and communicate using the
• Can register for periodic
newsletter in a particular subject
area thus keeping abreast of
• The Internet is the largest single
source of information for research
and education
– Companies use it to train employees
– Online courses for general users
• Search Engines make it easy to find
what you are looking for
• It has vast databases of documents
• Millions of euro/dollars are spent
online daily purchasing goods and
Booking airline tickets or other events
Online Auctions
Buying consumer products
Online Banking is growing steadily
How do I find things?
• Use a Search Engine
– Software that trawls the web looking for
new sites or updated sites
• Key in the URL
– If you know the URL of the site you want
to visit simply key it in on the address line
in the browser window
Search Engines
• Categorise web pages
– The software prepares an index of
pages by keywords or subject area
– It constantly searches looking for new
material on the WWW
– It presents a list of sites to the web
user with summaries of content
A Search Engine
• Provides the user with a facility to
enter a search word or phrase on a
chosen topic
• It then searches for websites
matching the search word/phrase
• It presents a list of possible sites to
the user, often with site summaries
• The user can choose which sites to
How do I get
• The Internet user needs
– A computer, network card (NIC) and a
– An connection to the Internet via an
Internet Service Provider (ISP)
– Internet software – A Browser such as
Internet Explorer
Irish ISP’s
• Different services available in
different regional areas
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