June 4, 2009 By Blake Harris
When it comes to preservation of digital government records, adequate storage capacity is always the fundamental concern, especially given the ever increasing quantity of digital information and statutory requirements for keeping public records.
However, over the years, I've heard several people raise the broader issue of preserving our cultural memories in the digital age. Part of the problem is that all current storage media deteriorates over a short period of time. Whereas with paper records, we could at least expect these to last a century or two, magnetic memory media and CD/DVDs, on the other hand, barely last decades at best. When it comes to data storage, density and durability have always moved in opposite directions - the greater the density the shorter the durability.
This is an issue currently being tackled by the Paris-based International Council on Archives. "It [is] clear that there is not a single solution for long-term preservation of digital records yet, but some experiences were reported from international organizations (namely Council of Europe and GSU)," notes Chiyoko Ogawa on the organization's Web site. "Archivists in various types of institutions should work together and try to exchange information and experiences in this regard. In particular we, as archivists, should define "long term" not as five years but centuries to tell our professional need of long-term preservation."
However, there is now a technological solution in sight. In a news release issued today, it was announced that researchers with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California (UC) Berkeley have come up with a new memory storage medium that can pack thousands of times more data into one square inch of space than conventional chips and preserve this data for more than a billion years!
"We've developed a new mechanism for digital memory storage that consists of a crystalline iron nanoparticle shuttle enclosed within the hollow of a multiwalled carbon nanotube," said physicist Alex Zettl, who led this research.
"Through this combination of nanomaterials and interactions, we've created a memory device that features both ultra-high density and ultra-long lifetimes, and that can be written to and read from using the conventional voltages already available in digital electronics."
"Interestingly," said Zettl, "the Domesday Book, the great survey of England commissioned by William the Conqueror in 1086 and written on vellum, has survived over 900 years, while the 1986 BBC Domesday Project, a multimedia survey marking the 900th anniversary of the original book, required migration from the original high-density laser discs within two decades because of media failure."
Zettl and his collaborators were able to crack the data storage problem by creating a programmable memory system that is based on a moveable part - an iron nanoparticle, approximately 1/50,000th the width of a human hair, that in the presence of a low-voltage electrical current can be shuttled back and forth inside a hollow carbon nanotube with remarkable precision. The shuttle's position inside the tube can be read out directly via a simple measurement of electrical resistance, allowing the shuttle to function as a nonvolatile memory element with potentially hundreds of binary memory states.
This illustration shows the configuration of a new digital memory storage device consisting of an iron nanoparticle shuttle that moves through a carbon nanotube when a voltage is applied. This memory device can pack a trillion bits of data into one square inch of medium and retain that data for a billion years. (Image from the American Chemical Society)
"The shuttle memory has application for archival data storage with information density as high as one trillion bits per square inch and thermodynamic stability in excess of one billion years," Zettl said. "Furthermore, as the system is naturally hermetically sealed, it provides its own protection against environmental contamination."
The low-voltage electrical write/read capabilities of the memory element in this electromechanical device facilitates large-scale integration and should make for easy incorporation into today's silicon processing systems. Zettl believes the technology could be on the market within the next two years and its impact should be significant.
"Although truly archival storage is a global property of an entire memory system, the first requirement is that the underlying mechanism of information storage for individual bits must exhibit a persistence time much longer than the envisioned lifetime of the resulting device," he said. "A single bit lifetime in excess of a billion years demonstrates that our system has the potential to store information reliably for any practical desired archival time scale."