Sony trials anti-piracy CD

Jackson's new album will be his first in six years

Sony music has issued promotional copies of Michael Jackson's forthcoming single You Rock My World with anti-PC technology to stop "file-swapping".

Jackson's record label has printed copies of the single to distribute to radio stations with key2audio technology that means it will only play in conventional CD players.

The company took the step after copies of the single - released on 7 October - appeared on the internet.

Britney Spears helped Jackson celebrate 30 years in pop recently

The new work by the "king of pop" - taken from Invincible, his first album in six years - was available on several websites after it had been copied from an unauthorised play on US radio.

In a statement issued by Sony music to BBC News Online, the music giant said it was trialling a number of anti-piracy technologies.

However, it said: "There are no plans currently to use similar technology on commercial releases of this record."

It added: "We continue to test available copy protection technologies, and our goal is to implement copy protection on a broader basis to deter digital piracy."

Investment

Anti-copying systems are still considered to be in their infancy. They are being developed by companies such as Macrovision and Midbar Technologies.

They have come about because of the success of file-swapping sites such as Napster.

Napster allowed users to take a music file - either taken from a CD or stored on a computer's hard drive - and trade it with an online partner.

To do this, Napster used file-compression technology called MP3, which allows music to be sent across the internet in far less time than it would otherwise take.

The process of taking music from a CD is called ripping. Once the music is ripped from the CD, it can be loaded on to a computer hard drive or put on a recordable compact disc.

Jackson produced the biggest-selling album to date with Thriller in 1982, which has sold about 42 million copies.

Sony is no doubt hoping that he can repeat that success with Invincible and recapture something of his glory years. The album took three years and a reported £20m ($28m) to make.