Buy a certain music CD - Dido’s first album, for example - and you’ll find that, while it plays in a CD player, it’s nearly impossible to copy the CD, or rip it and put it on an MP3 music player.

The same applies to The Beatles’ Let it Be… Naked album, released a couple of years ago. The album will play on a computer, but it’s not possible to rip the CD as MP3 tracks.

Music and film makers use something called Digital Rights Management, or DRM, to try to prevent their property from being freely copied. The two CDs above both use DRM.

What you can and can’t do
DRM is intended to stop people from making illegal copies of data, in this case, music or video files. Before CDs, DVDs and computers, it was very difficult to make a high-quality copy of a music track.

With digital recording, however, it’s possible to make perfect clones of a music track, and to keep making those infinitely. DRM is intended to stop illegal copying, while allowing people who have paid for the product – be it music, TV show or film – to watch it unhindered. However, as we’ll explain, this isn’t necessarily the case.

By the way, DRM is built into Windows and Mac OS – to find out more about DRM in Vista, take a look at the feature on Windows and DRM in our last issue.

But what is illegal copying? In the UK, an illegal copy means anything for which you have not directly paid (unless someone is deliberately sharing their material for nothing, see section entitled Licence to copy legally). So, running off a copy of a music CD you’ve bought so you can keep a copy of your favourite album in the car is illegal.

Burning a CD of music files you have paid for and downloaded from the internet is also illegal, although most music download services, such as iTunes, enable people to burn the song a set number of times. This differs in America, where making a single copy for your own use is fully within the law. There is no precedent of an individual being sued for making a single copy for personal use in the UK, but it’s not impossible.

Justifications for protecting music and video in this way are many. The original artists, engineers and record company need paying – it’s what they do for a living and they have their rights.

Uploading unprotected files with their work on them to file sharing sites like Kazaa or Grokster, and allowing hundreds of people to make copies loses the makers money. The music industry argues that this stops record labels investing in new bands as well as existing properties. Nobody is suggesting it’s ok to steal, and we’ll discuss whether the types of restrictions DRM places on files is fair in a moment.

But first it’s worth dealing with a couple of popular objections from people who oppose restrictions on file sharing. Frequently they cite people like Sir Paul McCartney or Sir Elton John and point out that these people are rich, so why not download their music rather than pay for it? There are two responses to this.

First, by all means those two and more besides can indeed afford to take the loss when someone downloads a song illegally, but the young, penniless musician who’s struggling isn’t in that position.