The more data we have, the more of it we want to preserve—and the longer we want it to endure. Hitachi may have created the ultimate archival storage medium using quartz glass. Physorg has the goods on the material, which is waterproof, impervious to "many chemicals," immune to radio interference, and capable of enduring temperatures as high as 1,000°C for a couple hours. Sounds resilient to me.
Data is stored on the glass using layers of binary dots that can be read by a conventional microscope. There are four layers in the current prototype, which squeezes 40MB into every square inch, a bit density close to that of old-school CDs. Hitachi expects higher densities can be achieved by adding layers.
The initial prototype, by the way, measures just 20 x 20 x 2 mm. Pretty sure I've seen it used in at least a couple of sci-fi movies over the years.
Given its relatively low storage density, this quartz glass storage tech seems likely to be useful only for archival applications. There's no word on the cost, though. Odds are it'll be rather expensive, since specialized equipment will probably be needed to read the glass efficiently, let alone write to it. Counting dots one by one under a microscope would get tedious pretty quickly.
Since you probably won't be storing precious data on high-tech glass anytime soon, what do you employ for archival media? Is there a stack of old optical discs tucked away somewhere safe, have you transitioned to hard drives, or do you use something else?