Hugh Pickens writes: "Digital storage devices have become ubiquitous in our lives but the move to digital storage has raised concerns about the lifetime of the storage media. Now Alex Zettl and his group at the University of California, Berkeley report that they have developed an experimental memory device consisting of a crystalline iron nanoparticle enclosed in a multiwalled carbon nanotube that could have a storage capacity as high as 1 terabyte per square inch and temperature-stability in excess of one billion years. The nanoparticle can be moved through the nanotube by applying a low voltage, writing the device to a binary state represented by the position of the nanoparticle. The state of the device can then be subsequently read by a simple resistance measurement while reversing the nanoparticle's motion allows a memory "bit" to be rewritten. This creates a programmable memory system that, like a silicon chip, can record digital information and play it back using conventional computer hardware storing data at a high density with a very long lifetime. Details of the process are available at the American Chemical Society for $30."