杏吧原创

A PC with a high-speed burner can clone a CD in a few minutes, and for only a few pence. So Sony of Tokyo is patenting a system that exploits the higher speeds used by computer CD drives to prevent copying (WO 03/063154). The music CD is pressed with its central hole slightly off-centre, while the label side of the disc includes asymmetric markings printed in heavy paint. This shifts the CD鈥檚 centre of gravity 鈥� not enough to matter when the disc is played at normal speed in a stereo, but a high-speed PC drive finds it 鈥渋mpossible to maintain stable rotation鈥�, says Sony. The disc drive then wobbles about like an unbalanced washing machine and the PC cannot make a faithful copy.