4. Sources of download data

Below are the most popular types of data that people want to download.

• Music
• Video or movies
• Other data

Music

There are many sources of music online. For example there are commercial sites such as iTunes and Amazon offering millions of tracks for sale. Each track is a digital file on their server. When you select a track, that file is downloaded and stored on your computer. To play it, you open up your favourite music client and select it from your 'library'.

Quite often an individual artist has their own web site where fans can purchase and download their favourite tracks. Again, each track is a digital file.

A typical music track is 3-5Mb in size so it is very quick to download and thousands can be stored easily

Video or movies

It is possible to purchase and download a movie. But the main problem is the sheer size of a complete film. Typically a DVD quality film (movie) is 5 to 8Gb, that is equivalent to around two to three thousand music tracks! You also need a fast broadband link to be able to download it in a reasonable amount of time.

For these reasons, it is more common to stream a movie rather than download it.

Other data

This includes software updates, complete applications ('apps), documents, image files and so on. Each one is stored as a file and opened with the relevant application. For example if you download a PDF file, it can be opened with the free Adobe Reader application.