With humanity’s seemingly insatiable desire for data, archiving it safely has become a bit of a problem. The various means we’ve been using all have tradeoffs in terms of energy and space efficiency, many of which change as the technologies mature. And, as new tech moves in, many earlier storage media become obsolete—to the point where it’s essentially impossible to read some old formats.

What if there were a storage medium that would be guaranteed to be readable for as long as humanity’s around and didn’t need any energy to maintain? It’s called DNA, and we’ve become very good at both making and decoding it. Now, two researchers have pushed the limits of DNA storage close to its theoretical maximum using a coding scheme that was originally designed for noisy communication channels. The result: an operating system and some movies were stuffed into genetic code at a density of 215 Petabytes per gram.

The new work comes courtesy of Yaniv Erlich and Dina Zielinski, who work at the New York Genome Center. They have built on a variety of earlier work. Not much challenge is involved in putting data into DNA: each place in the sequence can hold one of four bases: A, T, C, or G. That lets us write two bits per position. The trick is getting things back out reliably.