INTERNET

Communications & Networks

The Internet

The Internet is a Wide Area Network that covers the entire world

It can be thought of as many different, smaller networks connected together.

A vast quantity of information is available on the Internet. Mostly on web pages but there are also a huge number of files available for download.

The InternetThe Internet provides three main services:

The World Wide Web, which gives access to databases through browsing or searching

Electronic Mail, which provides one to one (or one to many) communication and exchange of information.

File Transfer, which makes it possible to send and receive large amounts of information.

Internet Ready ComputerAn Internet Ready Computer is a computer which can be online to the Internet within minutes of switching it on.It comprises:

A normal computer systemA Modem – This is a piece of hardware that allows your computer to send and receive data over a phone lineBrowser – A program designed to let you view pages on the internet (Internet Explorer or Netscape Navigator are two examples of browsers.Email program such as Outlook or Eudora

World Wide WebThe World Wide Web (WWW) is only part of the internet.The Web is made up of web sites, each of which

contains web pagesWeb pages are connected to other related pages using

hyperlinks. When you click on a hyperlink you are taken to another web page.

Any Web page can be accessed directly if its full web address or URL is known.

Web pages are written in a special language called HTML (Hypertext Markup Language)

HTML Example

HTML

Web Page

World Wide Web When you load a web page, you are downloading a

description of what the page should look like written in HTML

It is up to your web browser to take this information and use it to display the web page correctly.

A browser allows pages to be saved and printed and can move backward and forward through pages already accessed.

A browser also stores a history of recently viewed pages and can remember web page addresses by using bookmarks or favourites.

Connecting to the Internet

There are two main ways of connecting to theinternet:

Dial-up connectionYour computer uses a normal phone call to

connect to the internet using a modemThis type of connection is very slowIt also ties up your phone line so you can’t

make or receive calls.

Connecting to the InternetBroadband connection

Broadband connections are high speed connections to the internet. They can be over 10 times as fast as a dial-up connection.

ADSL (Asynchronous Digital Subscriber Line) uses normal phone lines and a broadband modem. (Asynchronous because you receive data much faster than you can transmit it)

A Broadband connection is always connected to the Internet.

Telephone calls can be made and received at the same time.

Online / OfflineA computer that is connected to a network is

said to be onlineWhen it is not connected to the network it is

offlineUsing a dial-up connection, you usually only stay

online for a short period at a time.Broadband connections are ‘always on’ which

means that you can remain online almost permanently.

To connect to the internet, you have to use a company called an Internet Service Provider (ISP)Your computer connects to the ISP’s computerThe ISP has a direct high speed connection onto the

internet.You access the internet through the ISP.The ISP usually gives you an email addressThey will often also give you some space on their

server for you to create your own web page.

Internet Service Providers (ISPs)

Normally to use an ISP you pay a monthly fee

Some ISPs don’t charge you by the month, but instead charge for the phone call when you connect to them.

Internet Service Providers (ISPs)

Search EnginesThe World Wide Web

contains millions of pages, on almost any subject imaginable

There is so much information that it is often quite difficult to find what you are looking for.

Search Engines Search engines are big

databases of web pages that you can use to find a page containing information in which you are interested

To use a search engine, you go to it’s web site and enter some keywords into a search box.

The search engine will then return a list of web sites that contain those keywords

Search EnginesOften, a simple search will return many pages

that are not really relevant to you.A complex search allows you to include many

different search criteria which should cut out most irrelevant web sitesyou can use conditions like AND, OR, NOTYou can restrict your search to certain domains.

Searching only .uk would search only uk web sites

Downloading Software

There is a large amount of software on the Internet that is available for you to download and use on your computer. It falls into several different categories.

Downloading SoftwareFreeware – This is software that you may

download and use free of chargeShareware – You may download this and use it

for a trial period. After this you must register the software, usually by paying the author a fee.

Commercial Software – You can buy some software online using a credit card and then download it to your computer

Mobile Internet Technology Increasingly, people are using the

internet from palmtop and laptop computers, to read email and access the world wide web.

Palmtop computers can often be connected to a mobile phone which is then used to connect to the internet.

A Smartphone

Mobile Internet TechnologyA smartphone is a PDA with a

built in mobile phone. You can use it like a normal phone and also access the web and email with it.

Palmtop computers and mobile phones use different operating systems and wireless application protocal (WAP) browsers to connect to the WWW.

A Smartphone

Video ConferencingThis can be used to

conduct a meeting or conference between two or more people in different places.

It requires a computer system, web cam and a network connection between everyone involved.