In an era where a sizable portion of the world's literature is stored in some digital form or medium, the relative shelf life of such mediums leave a lot left to be desired. The irony is that while efforts in "archiving" the printed medium of centuries long past were intended to preserve such works, the printed medium will more than likely outlast the digital collection it has been copied into. This is due to theoretical limitations in utilizing semi-conductors for such tasks.
Researchers have discovered an alternative to the traditional semi-conductor approach by using some modern techniques in the field of nanotechnology. Digital information is usually stored in the medium as a machine-readable set of 1's and 0's. By storing an iron nanoparticle inside a carbon nanotube in one of two positional states, one can induce the iron to move between the states in the presence of electricity. This can effectively represent the machine-readable 1's and 0's required by the system.
Greater storage space can be achieved by packing components of the digital medium into dense clusters. This relationship is directly proportional: the greater the density of the medium given a physical space, the greater the storage offered. Unfortunately, semi-conductor placement also have an inversely proportional relationship to its shelf-life: the greater the density of the medium, the less the shelf-life will be. The nanotube system is believed to be relatively stable in this regard, as nanotubes can be packed as densely as needed while yielding the same shelf-life: over a billion years.
Nanoscale Reversible Mass Transport for Archival Memory [Nano Letters, ACS Publishing]