How big is an exabyte? One million terabytes. In 2007 the world’s total computer data was, compressed, 295 exabytes. How many hard-drives would it take to stores all that data? Assuming you get a large 2 tb hard-drive it would take 148 million! Now what if I told you you could store all that in less than one gram of DNA? Nature and Science both have reports of a paper, published in Science, that shows how DNA can be used to store data.
DNA is able to store the information needed to create any living thing on the planet and now it’s also been used to store a 53 000 word textbook (as well as the contained 11 images and a Javascript programme). In theory a single gram of DNA is capable of storing 455 exabytes of data! This makes it the densest data storage medium we have. On the downside storing and retrieving the information currently requires very expensive equipment and your own lab. So in that sense it’s not useful now. But the data could be stored for centuries, take up almost no space and, because it uses the same mechanisms as living cells, isn’t going to become obsolete for billions of years.