BranFlake5 :
10 Years ago we had 128MB on a micro SD card, today we have 128GB, in ten years will we have 128 TB?
Probably not. It took SSDs over 30 years to really take off.
Current NAND gates are based on plain old electricity and relatively big components (2 transistors separated by a metal-oxide layer). We are reaching scales where even at very low voltage levels,
electron leakage occurs (same goes for CPUs) - in layman's terms, an electron can jump to another conductor - the higher the
voltage, the farther the electron can jump. That is why we're trying to lower the voltage, BUT whether a certain bit gate returns 1 or 0 depends on the threshold voltage, which we have to measure and as you lower the voltage, it gets
harder.
Luckily, there are different methods of data storage using
spintronics or
nanoplasmonics (quantum memory), that will allow much higher memory densities and even smaller devices - by this time, regular HDDs might be replaced by holographic "discs" (basically a 3D HDD) with exabyte capacities. But as soon as these technologies become commercial, we'll probably see the same rapid improvements as with current SSDs.
@dgingeri: while phase change memory does have much better performance and durability, it doesn't allow much higher memory densities than flash (they are heat-based) + they are harder to scale below 45nm than flash.