sentences:  No commercial product based on 3Doptical data storage has yet arrived on the mass market, although several companies are actively developing the technology and claim that it may become available 'soon'.Current optical data storage media, such as the CD and DVD store data as a series of reflective marks on an internal surface of a disc.In order to increase storage capacity, it is possible for discs to hold two or even more of these data layers, but their number is severely limited since the addressing laser interacts with every layer that it passes through on the way to and from the addressed layer.