Generally, when you talk about storage, you can pick one:
Fast, but volatile
Non-volatile, but slow.
You want both, but forget about it. It's not possible. At least not yet.
Theoretically, it's possible, of course. Researchers have known that it's theoretically possible to have it both ways, providing you could use phase-changing material. That's a fancy name for a material that changes from crystalline to amorphous and back again. But they couldn't make the material needed for the wires.
The lithographic process used to make the material also damaged the material when it reached the required thickness -- a whopping 100 nanometers. Since the surface was damaged, it couldn't store and retrieve data.
Hopes were fading fast, at least among those who actually understood the problem. Meanwhile, the rest of us were blissfully unaware, too busy cursing ourselves for forgetting to plug in our iPod.
But a team of researchers seems to have the answer, according to this Technology Review article. Ritesh Agarwal, an assistant professor of materials science and engineering at the University of Pennsylvania, and his research buddies have found a way to "grow" phase-changing nanowires using the elements germanium, antimony and tellurium.
A few tweaks here and there to the room temperature and, kazam!, they found out the tiny wires could write and retrieve data at 50 nanoseconds. That's 1,000 times faster than flash memory and maybe even faster than The Flash, but I don't know for sure. I'm not that much of a comic-book geek.
But how long can it store data? Well, we don't know for sure, because, heck, it probably is still going. However, researchers estimated it could hold data for a fat 100,000 years. Which is more than I can say for those floppy disks sitting around, unreadable because nobody has a floppy disk drive anymore.
You can find out all the nano-geek details online at the Nature Nanotechnology, but you do have to pay for the full article.