Vapourware: The tech that never was

FMD
The Fluorescent Multilayer Disc (FMD) promised ten times the storage of a DVD, long before Blu-ray was launched. Thanks to the wondrous miracle of 3D data storage (more here), FMDs were theoretically capable of having in excess of 100 layers of data -- that's 50 times more than a DVD has even today. This led to promises of discs that could store a terabyte of digital information, making these conventionally sized circular discs as capacious as 2008's most capable hard disk drives.

The first prototype demonstration of FMDs appeared in 2000, in the form of a 50GB disc. This was incredible -- the average capacity of a hard disk at the time was significantly lower than 50GB. But the problem here was that Constellation 3D -- the company that was developing the format -- was still using red lasers, just like a DVD. Blue lasers, such as those now inside Blu-ray systems, were needed in order to achieve terabyte disc capacities. This advancement never happened.

Sadly, money ran out and the FMD never saw the light of day. Constellation 3D's patents were later acquired by D Data, and are now in use inside FMD's successor technology, Digital Multilayer Disc. Currently capacities, still using red lasers, are around the 30GB mark.

As a matter of fact...
A miniature version of the FMD was in development, too. It was to be about the size of a credit card and would have offered a massive advantage over flash-based storage for digital cameras, although it's debatable whether this would ever have been economically viable.