TDK has developed a prototype optical disc that can hold up to 320 Gbytes of information -- that's more than six times the current highest-capacity media available.
The 12-centimeter disc has 10 recording layers, each of which can store 32 Gbytes. In comparison a Blu-ray Disc can hold 25GB on each layer, and a dual-layer disc is the highest capacity generally available at present.
As more layers are added to a disc it becomes more difficult to reliably read and write data because the laser has to shine through the layers. To help get around this, TDK engineers created a disc that uses clearer plastic so that more light can be shone through.
In 2006, TDK prototyped a write-once recording medium having six layers, each of which has a capacity of 33.3 Gbytes (200 Gbytes in total).
All three prototypes have something in common: their manufacturers have announced no plans to commercialize the discs. Their use in Blu-ray Disc players and recorders would require standardization efforts at the Blu-ray Disc Association and likely minor hardware changes in disc drives. So for now they serve as an indicator to where optical disc technology stands in the research laboratory.