ICT

The Internet

The Internet is a worldwide system of interconnected computer networks [network: a group of interconnected computers ]. When you connect your computer to the Internet via your Internet Service Provider (ISP) you become part of the ISPs network, which is connected to other networks that make up the Internet.

The World Wide Web

The World Wide Web (WWW or Web for short) is the part of the Internet that you can access using a web browser [web browser: an application used to browse the Internet or view web pages ] such as Internet Explorer [Internet Explorer: a web browser developed by Microsoft ] or Firefox [Firefox: a web browser developed by Mozilla ]. It consists of a large number of web servers that host websites. Each website will normally consist of a number of web pages. A web page can contain text, images, video, animation and sound.

Accessing web pages

You can access a website or web page by typing its URL (Uniform Resource Locator) into the address bar of your browser. An example of a URL is http://www.bbc.co.uk.

URLs will have the format 'http [Hypertext Transfer Protocol (HTTP): a request/response standard, web browsers send requests and websites or servers respond to requests ]' and a domain [domain: an area of control or management, eg bbc.co.uk is controlled by the BBC ] (such as .uk [.uk: the Internet country code for the United Kingdom ]). What goes in between is arbitrary, but often has the term "www", eg http://www.bbc.co.uk, but it doesn’t have to, eg http://news.bbc.co.uk).

Https is the secure version of http. When you use https any data [data: information without context, eg a list of students with numbers beside their names is data, when it's made clear that those numbers represent their placing in a 100 metre race, the data becomes information ] you send or receive from the web server is encrypted. For example, when banking online https is used to keep your account details safe.

Most sites have a page that links the user to the other main areas of the site. This is called the homepage.

Web pages are connected by hypertext links. When a link is clicked you will be taken to another page which could be on another server [server: a computer that provides services to users, eg access to shared files, web hosting, file storage ] in any part of the world.

What is an intranet?

An intranet is a network that works like the Internet but is only available within a particular organisation, not to the public. An intranet may have web pages used to share company specific data within that company, such as internal telephone numbers or details of employee benefits.

Connecting to the Internet

To connect to the Internet the following are needed:

  • a computer
  • telephone line (cable being the exception)
  • modem [modem: a piece of hardware that connects a computer to the Internet ] and/or router [router: a device for connecting computers and other network capable devices together to form a network ]
  • an ISP (Internet Service Provider)
  • Web browser [web browser: an application used to browse the Internet or view web pages ], eg Internet Explorer [Internet Explorer: a web browser developed by Microsoft ], Firefox [Firefox: a web browser developed by Mozilla ], Chrome [Chrome: a web browser developed by Google ], Safari [Safari: a web browser developed by Apple ], Opera [Opera: a web browser developed by Opera Software ] etc.

Internet Service Providers (ISPs)

ISPs provide access to the Internet. Commonly used ISPs include Sky, Virgin and BT but there are many more. Most offer the same basic package of Internet access, email [email: electronic mail - a message written or typed on a computer and sent electronically rather than by post ] addresses and web space [web space: the amount of storage given to a website ].

You need a web browser to view web pages [web page: a page designed for, and viewed in, a web browser ]. The most widely used are Internet Explorer and Firefox. All browsers will have a number of similar features to help you use the web such as:

  • forward and back buttons to move between pages
  • a history folder which stores details of recently visited web pages
  • a stop button if a page is taking too long to load
  • favourites and bookmark options to store often visited pages
  • options to cut, copy, paste, save and print elements of web pages

A connection made to the Internet will be either analogue [analogue: continuous data, eg the second hand on an analogue watch displays each second and the space in-between ] or digital [digital: data measured at discrete intervals, eg a digital watch typically moves from displaying one second to the next without displaying the values in-between ]. It is important to know the difference between the two and the technologies they use.

Analogue connection

Dial-up

A dial-up modem converts digital [digital: data measured at discrete intervals, eg a digital watch typically moves from displaying one second to the next without displaying the values in-between ] signals from a computer to analogue [analogue: continuous data, eg the second hand on an analogue watch displays each second and the space in-between ] signals that are then sent down the telephone line. A modem on the other end converts the analogue signal back to a digital signal the computer can understand.

A workstation is connected to an analogue modem. The analogue modem is then connected to the telephone exchange analogue modem, which is then connected to the internet

An analogue Internet connection

The maximum theoretical connection speed is 56Kbps [kilobits per second (Kbps): a measurement of the speed data is being transferred at ]. Dial-up is very slow by today’s standards and in real world use will typically result in a download [download: the transfer of a file or files from one computer connected to the Internet to another ] speed of roughly 5KBps [kilobytes per second (KBps): a measurement of the speed data is being transferred at ].

Phone calls cannot be made whilst connected to the Internet.

Digital connections

ISDN

An ISDN (Integrated Services Digital Network) capable phone line can provide connection speeds of up to 64Kbps (single channel) or 128Kbps (dual channel) using a terminal adapter often referred to as an ISDN modem [modem: a piece of hardware that connects a computer to the Internet ]. The terminal adaptor removes the need to convert digital [digital: data measured at discrete intervals, eg a digital watch typically moves from displaying one second to the next without displaying the values in-between ] signals to analogue signals before they’re sent down the telephone line, this results in a more reliable Internet connection [Internet connection: a computer's or another internet-enabled device's connection to the Internet ].

ADSL

ADSL (Asymmetric Digital Subscriber Line) provides connection speeds of up to 24Mbps [megabits per second (Mbps): a measurement of data transfer speed ] and uses a telephone line to receive and transmit data [data: information without context, eg a list of students with numbers beside their names is data, when it's made clear that those numbers represent their placing in a 100 metre race, the data becomes information ].

The workstation is connected to a digital modem. This is connected to thte telephone exchange broadband modem, which in turn is connected to the internet.

A digital Internet connection

The speed that data can be transferred is dependent on a number of factors:

  • Phone lines were designed to carry voice signals - not data. Signal quality can vary between lines and whilst it doesn’t affect voice signals, it does affect data transmissions.
  • The distance between your house and the telephone exchange [telephone exchange: a system of electronic components that connects telephone calls and has been adapted and expanded to facilitate connections to the Internet too ] has an effect on the speed at which data is transferred. A distance of 4Km is considered the limit for ADSL technology, beyond which it may not work.

An ADSL modem/router [router: a device for connecting computers and other network capable devices together to form a network ] is needed for broadband [broadband: high speed Internet access ] Internet access over ADSL. This is usually provided by your ISP [Internet Service Provider (ISP): Internet Service Provider - needed in order to access the Internet, they also provide services such as web space and email ].

Phone calls can still be made whilst connected.

Cable

Cable companies do not use traditional telephone lines to provide broadband Internet access. They have their own network [network: a group of interconnected computers ], a combination of co-axial copper cable and fibre optic cable [fibre optic cable: cable that carries data transmitted as light ].

With their purposefully built infrastructure cable companies are able to provide speeds of up to 50Mbps - considerably faster than the highest available ADSL speed (24Mbps).

A cable modem/router is needed for broadband Internet access over cable. This is usually provided by your ISP.

The making and receiving of phone calls is not affected because the telephone line is not used.

Why use broadband?

Most people in the UK access the Internet using broadband [broadband: high speed Internet access ] because it’s much faster than the other methods. Broadband access allows feature rich web pages [web page: a page designed for, and viewed in, a web browser ] (ones that have lots of graphics [graphics: visuals intended to brand, inform, illustrate or entertain, eg photographs, drawings, maps, diagrams etc. ], videos, sound, animations etc) to download [download: the transfer of a file or files from one computer connected to the Internet to another ] quickly and it allows users to quickly download large files (like music or video clips). Faster Internet connections [Internet connection: a computer's or another internet-enabled device's connection to the Internet ] also mean that the response time between clicking on a link and the new page appearing are reduced.

The download times below are calculated based on each connection's maximum theoretical download speed.

ISPs advertise speeds as 'up to', for example, 'up to 8Mb'. This means that the maximum speed you will achieve is 8Mb but that you're unlikely to achieve 8Mb all the time.

What can you do on the Internet?

  • browse websites [website: a web page or group of web pages hosted on one web server and viewed in a web browser ]
  • send and receive email [email: electronic mail - a message written or typed on a computer and sent electronically rather than by post ]
  • download [download: the transfer of a file or files from one computer connected to the Internet to another ] media files, eg Mp3s or video files
  • watch streamed [stream: delivery of data as and when it's needed rather than all at once, eg a streaming video downloads as it's watched rather than in advance ] video, eg BBC iPlayer, YouTube etc
  • check your bank balance and make payments
  • buy goods from online shops
  • access educational material from your school’s Virtual Learning Environment (VLE)
  • create, store, edit and share your documents using web-based applications [web-based application: an application that runs within a web browser ], eg Google Docs
  • interact with friends on social networking [social networking: the act of building or furthering existing friendships and relationships in an online setting ] sites, eg Bebo, MySpace, Facebook etc
  • write a blog [blog: an online publication written by an individual or a group of individuals that covers a subject of their choosing ]
  • sign-up to forums [forum: also known as a message board, a platform for exchanging written messages with other users, a place for discussion ] and discuss topics that interest you with like-minded individuals
  • game with friends
  • instant message family and friends
  • share photos and videos
  • complete free tutorials covering a wide range of subjects

Searching the web

Finding the exact information you want on the web [web: includes all of the web pages accessible via the Internet ] requires skill and practice. There are thousands of pages on any given topic.

Search engines

Google search page

A search engine is a service which helps you find the information you want on the Internet. Search engines continually trawl the net for new websites [website: a web page or group of web pages hosted on one web server and viewed in a web browser ] cataloguing them into an index. Some commonly used search engines are Google, Yahoo and AltaVista, but there are many others.

Search terms

When you go to a search engine you are given a search box into which you enter the key words of your topic. For example, if you enter the word rock you will likely get links to pages about geology, music and building societies.

Let us say we want information on rock music. If you type in rock music it is likely the search engine will bring up links to many pages about rocks, rock climbing and music. However, if you try typing in "rock music" (with quotes) the search engine will treat it as a phrase and bring up details of web pages [web page: a page designed for, and viewed in, a web browser ] containing the words rock music in that order.

Advanced search terms

Entering rock + music will bring up documents containing both words. Entering rock + music - climbing will bring up documents containing the words rock and music but with no reference to climbing.

Back to Revision Bite