Bacteria-based storage systems can save data for thousands of years while protecting it against nuclear explosions. Atoms can hold 250 terabits of data per square inch of surface area. There are organic thin-film structures with more than 20,000 write-read-rewrite cycles.
There's fantastic stuff that's on the horizon for boosting storage systems' speed and capacity almost beyond imagination, so here's a look at some of the most promising.
Research from two prominent universities indicates that it is not only possible but also practical to store digital data in the genome of a living organism and retrieve that data hundreds or even thousands of years later, after the organism has reproduced its genetic material through hundreds of generations.
"Consider a millilitre of liquid can contain up to 1 billion bacteria, and you can see that the potential capacity of bacteria-based memory is enormous," Pak Wong, Pacific Northwest National Laboratory (PNNL) lead scientist, noted in a 2003 paper. (Note: A millilitre is a thousandth of a litre).
In their paper, Wong and a group of PNNL researchers described an experiment three years earlier in which they stored about 100 base pairs of digital information (roughly one encoded English sentence) in one bacterium.
This year, scientists at Keio University Institute for Advanced Biosciences reported similar results in their research, claiming that they successfully encoded "e= mc2 1905!" -- Einstein's theory of relativity and the year he enunciated it -- on the common soil bacteria Bacillus subtilis. According to the scientists, DNA-based data can also be passed on for long-term preservation of large data files
One of the challenges faced by Wong's group was providing a safe haven for DNA molecules, which are easily destroyed in any open environment inhabited by people or potential enemies of nature. The so-called double-strand break of DNA, which is usually fatal, can be caused by common unfavorable environmental conditions, including excessive temperature and desiccation/rehydration.
Mindful of DNA's fragility, the PNNL scientists provided a living host for the DNA that tolerates the addition of artificial gene sequences and survives extreme environmental conditions. It was essential that the host with the embedded information be able to grow and multiply, says Wong.
Perhaps the biggest challenge faced by the researchers was retrieving embedded messages. "The retrieval of the information stored in a bacterium remains a wet-laboratory process that requires a certain amount of time and effort to accomplish. It took us about two hours in 2000 to complete the information extraction process," says Wong, adding that it will take decades to develop data-retrieval techniques similar to those of today's commercial IT systems.
Most of the potential applications for DNA-based data storage relate to the core missions of the U.S. Department of Energy (DOE), which funded all of Wong's work. Other security-related applications include information-hiding and data steganography -- the hiding of data inside other data -- for commercial products, as well as those related to national security.