In the early days of computers, a hard drive with a few megabytes was an unimaginable amount of storage. Then we hit 100 megabytes, then a gigabyte, then a terabyte, and sizes are still increasing rapidly with a 10 terabyte hard drive arriving earlier this summer.
However, at some point we will hit a wall as existing magnetic storage technology gets shrunk as far as it can go. Solid-state memory can carry us a bit further thanks to 3-D stacking techniques, but even that's not as good as it gets. There's a natural solution that can do much better.
That solution is DNA. Yes, the double-helix building-block of life that tells your body what to do could be the ultimate future hard drive.
DNA stores information in combinations of four base pairs, which wouldn't be hard to adapt to our existing binary system. In fact, researchers have already done it, both for writing and reading information.
The two big payoffs of using DNA are storage density and longevity. In terms of storage density, a single drop of DNA-filled fluid can store the equivalent of 300,000 terabytes of digital data. So instead of a building housing 30,000 10TB hard drives, you could carry around a small eyedropper.
Then there's the fact that the best hard drive out there is only going to hold its data 100 years, and solid-state drives only hold information a few months without power. DNA can last for a thousand years on its own, and researchers have found a way to improve that.
A team of researchers at ETH Zurich headed by Robert Grass encoded some DNA with data and then stored it in silica spheres. Then they heated the spheres to 160 degrees for a week, which the researchers claim equals 2,000 years of the DNA being stored at 50 degrees.
Afterward, they were able to read the data off the DNA again with no errors. They claim DNA stored this way could potentially last millions of years.
Of course, there are a few roadblocks before DNA takes over. Right now it's really hard to encode and read. It takes hours of researchers in a lab with high-end equipment to do a few kilobytes, and costs thousands of dollars per megabyte.
Also, unlike a computer hard drive, you can't search for information. You'd have to start decoding information from the beginning until you find what you want. So finding specific pieces of information is going to be a chore, although researchers are working on a tagging system that could help.
There's also the problem of corruption. While DNA lasts a long time, it does create errors every time it replicates. To get around this, you have to encode the same information on several DNA strands and then compare them when you read it to weed out errors.
In other words, while DNA could be the future of data storage, don't expect a DNA-based hard drive in your computer for at least a few decades.