A team of scientists from Japan’s National Institute of Materials Science (NIMS), Seagate and Tohoku University have developed a dual-layer HDD technology that could enable recording densities of more than 10 Tb/sq. inch. In theory, this would increase the maximum capacity of a 10-plate HDD from 30TB to 120TB.
So far this is only research, to real prototypes, and even more so to commercial products is still very far away. Nevertheless, in the future, based on this technology, it may be possible to realize separate recording of information on three or even four layers, which will further increase the available HDD capacity.