There are many means of storing data nowadays, but few of them can claim to have almost unlimited staying power, and the ones that do aren't commercially available anyway.
What Hitachi has to show isn't commercially available either, but it is a concept that has very high odds of catching on.
After all, it isn't every day that someone invents a piece of perfectly transparent glass that can hold as much data as a CD and has the potential of going well beyond that information density.
Granted, it isn't quite accurate to compare the two in that manner. The piece of quartz glass made by Hitachi is a small square with two-centimeter width (0.78 inches). Still, the slate can hold 6 MB of data, inscribed as binary-coded dots in four layers.
This is the same areal density as that of compact disks, but Hitachi believes it can take things much further.
That isn't the main asset of the glass though. Hitachi seems to be more enthusiastic about the endurance, the ability to survive, unscathed, being exposed to a 1000 degrees C flame for up to two hours.
The glass is resistant to most chemicals as well, and will not be negatively affected by magnets, water exposure or radio waves either. After all, the data isn't magnetically written, but etched physically into the transparent material.
Unless the glass is broken, something that isn't easy to do, the data should survive indefinitely. This makes Hitachi's quartz slate a very convenient component in databases meant to store data for future generations, like the subterranean areas where toxic waste was dumped.
The only pitfall with this plan is the same as with all other such plans: the means of storing data may be super-tough, but the hardware capable of reading it isn't as long-lived. Then again, assuming civilization progresses instead of collapsing during the next millennium, it should be a simple matter for our advanced descendants to figure out how to read the slate, even if no hardware or instructions as to how to build it survive. This is assuming Hitachi decides to market the technology, which it hasn't, yet.