Only last month we were heralding Pioneer's development of a 400GB optical disc, and just a month later its researchers have popped on another four layers and 100GB of storage to create a half terabyte disc. In actual fact, to be fair, Pioneer has simply confirmed the "viability" of such a disc, which may or may not exist in a laboratory somewhere. The company believes that the technology, based on the same techniques used to make current 25GB and 50GB Blu-ray discs, is easier and cheaper to produce than holographic discs...