An optical storage technology that uses multiple recording platters for higher capacity. Typically, DVDs and Blu-ray discs are available in two or more layers. In 1994, at its Almaden Research Center in San Jose, CA, IBM prototyped multilayer technology. See DVD and Blu-ray.
Sandwiched together, the individual layers are accessed by focusing the lens on one of the surfaces.
Sides and Layers
DVDs come in any combination of single or double sided with single or double layers. This shows the laser beam contacting the recorded surface in all of the possibilities.