US band My Morning Jacket has waded into the debate over copy protection by sending fans DRM-free copies of its album.

The move follows complaints by fans who had bought copy protected Sony BMG CDs and found they were unable to copy the band's music to iPod devices.

The band's manager, Mike Martinovich, told Rolling Stone magazine that Sony BMG should drop DRM on CDs entirely.

Edward Felten, professor of computer science at Princetown University, who exposed the security breaches in both the DRM software and subsequent 'uninstallers' and patches, said that it is not possible to have a CD-based DRM system without installing software on the listener's computer.

But such software would have to be installed covertly, and made difficult to find, so that the user cannot easily uninstall it.

Professor Felten pointed out that installing a program secretly on a user's computer is precisely what spyware programmers do.

"Having set off down the road of CD copy protection, the music industry should not be surprised to have arrived at spyware, because that's where the road leads," he said on his blog.