martes, 16 de junio de 2009
New Ultradense Memory Chip to Last a Billion Years?
Nanotube Memory Array
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Your blog might be popular today, but how will you preserve it for future generations? Enter memory chips that can last for over a billion years.
Newly developed nanoscale devices can pack a trillion bits of data—equal to about 25 million textbook pages—into a square inch (6.5 square centimeters) of material made from multiwalled carbon nanotubes.
Storage media can become degraded and unreadable due to environmental conditions, mechanical wear, and other factors. Normally, the more that's packed onto a memory chip, the faster it wears out.
DVDs, for instance, can hold a hundred billion bits per square inch, but are only expected to remain readable for 30 years.
But carbon nanotubes are formed by the strongest bonds in nature—carbon-carbon bonds—making them corrosion-proof, researchers say.
The system's longevity may be overkill, admitted research leader Alex Zettl, but he said that long life is necessary for fundamentally sound storage.
"There are several components to a memory storage system, but the heart of the system, where the bits are actually stored, should be as robust and long-lived as possible," said Zettl, a physicist at the at the Lawrence Berkeley National Laboratory at the University of California, Berkeley.
"A billion-year lifetime for this critical component allows us to call this part done and concentrate on the other components."
The project is still in the research stage, but an early model may be available in two years.
To create the new chip, the researchers used a series of carbon nanotubes containing crystalline iron nanoparticles—each a fraction of the width of a human hair. The nanotubes move back and forth when low voltage is applied to the chip.
The position of the nanoparticle can be precisely read by measuring electrical resistance, and its position can indicate either a state of zero or one in binary code.
Zettl's team compared the new chip to the still-legible writing at Egypt's 4,000-year-old Temple of Karnak, as well as to England's well-preserved Domesday Book of 1086.
A reliable archival memory device should be one that would last at least several centuries, if not several millennia, Zettl said.