You know how we keep saying that everything works better with lasers? It looks like our trusty old magnetic platter hard drives are no exception, since blasting them with laser pulses instead of magnetic fields can apparently make them perform about a thousand times better.
Lasers and magnets generally don't get along very well. Lasers create heat, and heat tends to destroy the little magnetic fields that represent the ones and zeros that make up our data on a regular magnetic platter HDD.
However, if you use magnets that are fancy enough (like ferrimagnetic nanoislands made out of an alloy of iron and gadolinium) and a fast enough laser (like one that fires pulses lasting just a few femtoseconds), the heat generated by the laser pulse will cause the magnetic state of the nanoislands to rapidly switch back and forth, blowing centuries worth of magnetic theory completely out of the water.
There are all kinds of advantages to using lasers instead of magnets for storing data magnetically. Lasers are more efficient, requiring lower power to operate, so that's good. And the nanoislands that the laser uses to store magnetic data can be smaller than the bits on a conventional magnetic HDD, meaning that you can increase the bit density by a factor of 15 or so, and that's nice. But the real kicker is the speed: the laser pulse itself lasts only 60 femtoseconds, with the magnetic switching completing itself in under five picoseconds. For those of you keeping track, light travels about one millimeter in five picoseconds, and it takes a hundred times that long for your computer to add two integers. This means that our hard drives could be writing data about a thousand times faster than they are now, in the terabytes-per-second range.
The only problem, at this point, is that while lasers are great at writing magnetic data, reading it is another challenge entirely. The researchers seem to have used a fancy type of X-ray spectrometer that can read magnetic fields to check and see if they were writing the data that they thought they were, but until those get shrunk down to HDD component size (or someone comes up with something clever), we may be stuck just writing our data really really fast and not reading it ever again.