If we stop for a moment and look back at the progress made in the last 60 years it is mind boggling. Sixty years ago, it was 1955, the very first commercial transistors were appearing on the market, although the vacuum tube still reigned. And if you measure a (small) vacuum tube in nm (billionth of a meter) you discover that its size was about 50 million nm. And those first transistors were tiny in comparison: about 10 million nm, five times smaller than vacuum tube. Sixty years later transistors have shrunk to 14 nm, 4 millions times smaller.
This information is provided in a very nice infograph by IBM.
In that infograph IBM tells the story of the evolution of transistors and of the way to store a single bit. Storing a bit using a magnetic substrata involves about 1 million atoms. According to IBM researchers the smallest number of atoms to store a single bit is 12, that is to have a practical way of storing them using today's technology practices. That would mean a 100,000 increase in density with respect to commercial products we use in 2015.
IBM claims that this increase in density is what is needed to face the explosion of data. Every day we create 2.5 quintillion of bytes (that is billion of billions). Even more impressive is the fact that 90% of the data we have today have been created in the last 2 years.
And there is no end on sight (although we know that limits exist). In the labs researchers are looking at ways to use single atoms to store a bit (spintronics) and scientists are speculating on the possibility to use quantum states to store an enormous amount of bit per single atoms! This will be for the real future.