It borrows the clever magneto-optical system from Sony's popular little MiniDisc audio-recorder to stack magnetic data within concentric grooves on the platter's surface.
Just sounds like yet another one of the many dumb decisions the board of Sony have made since their late-90s heyday, a time when they could do no wrong and everyone thought the MiniDisc was the future.
When listening to music, the sound of the PC was obliterated by a battered old Sony amp and speakers plugged into the motherboard's optical port via an equally battered MiniDisc player with optical-in that functioned as our DAC.