The cost per gigabyte has been dropping steadily. As little as five years ago, a 500 GB hard drive was considered an excessive amount of storage for any organization but the Library of Congress. "How will my application ever fill that much space?" we asked.
And yet, here we are in 2011 with our two TB drives full. It's not just a matter of increasing capacity, however; larger drives do actually require larger housings, because there's only so much storage density you can pack on a platter (or a flash chip, for SSD users). In traditional spinning platter drives, additional platters are needed to increase capacity beyond a certain point. This, in turn, increases the height of the drive. For space-constrained applications (which many embedded applications are), there is not a lot of room to grow. Certain 1-U rackmount cases, for instance, will have a hard time accommodating taller drives, and most hot-swap trays aren't set up to accept unusually-sized drives.
Enter household table salt. In a brilliant move or possibly an accident that proves it's OK to eat in the lab despite OSHA warnings, a Singapore research team led by Dr. Joel Yang have refined a process for increasing hard drive density sixfold. The secret ingredient? You guessed it: sodium chloride.
It's a simple and elegant solution, really. The inclusion of salt crystals in solution during the lithography process of platter manufacturing causes the bit cells to align in a more regular and dense fashion, amplifying capacity from 0.5 Terabits/in2 to 3.3 Terabits/in2.