Distributed architecture

09 Jun 2009

by: By John Adams

SCIENTISTS in the U.S. have developed a technique that could allow more than a terabyte of video to be stored on a button-sized device, a discovery that could finally open the door to truly distributed architecture in video surveillance solutions.

When you consider the huge storage demands of megapixel cameras it makes sense for manufacturers to adopt distributed architecture models. The only trouble is that current SD storage technology is stalled at 32GB. While 64GB is due in the near term, it will only store a live 1080i video stream for a week.

Fact is, we can’t talk about true distributed architecture in CCTV systems till remote storage at high resolution and full frame rate gets up to 30 days – that demands at least 256GB. But at this size there are issues of cost. Large NAND and SD storage units are very expensive - especially once you’ve multiplied them across 100 or 200 cameras.

It’s this need for more capable remote storage solutions that makes a new technique jointly developed at UC Berkeley and UMass Amherst so exciting. In terms of storage density, the discovery could see the contents of 250 DVDs squished onto a storage device the size of a coat button.

According to researcher Ting Xu, the discovery is built around the fact that molecules in a thin film of block copolymers - two or more chemically dissimilar polymer chains linked together - will self-assemble into an extremely precise pattern when spread out on a surface, much like a formation of soldiers.

Xu says that for 10 years researchers have tried to exploit this characteristic for use in semiconductor manufacturing but the stumbling block is that this self assembly falls apart the bigger the surface area becomes – and once disrupted it’s impossible to read or write to the molecules.

Now researchers Thomas Russell and Xu have layered the film of block copolymers onto the surface of a commercially available sapphire crystal.

“When the crystal is cut at an angle - a common procedure known as a miscut - and heated to 1,300 to 1,500 degrees Centigrade (2,372 to 2,732 degrees Fahrenheit) for 24 hours, its surface reorganizes into a highly ordered pattern of sawtooth ridges that can then be used to guide the self-assembly of the block polymers,” says Xu.

“Using this technique we were able to achieve defect-free arrays of nanoscopic elements with feature sizes as small as 3 nanometers, translating into densities of 10 terabits per square inch. One terabit is equal to 1 trillion bits, or 125 gigabytes.”

The potential of this discovery is enormous and if commercially developed such vast, compact storage units would make a mockery of Moore’s Law. Significantly, because the sapphire crystals come in a variety of sizes, there are few limitations to how large this block copolymer array can be produced, the researchers said.

"We can generate nearly perfect arrays over macroscopic surfaces where the density is over 15 times higher than anything achieved before," said Russell. "With that order of density, one could get a high-definition picture on a screen the size of a JumboTron."

Other developments in ultra-dense storage employ lithography and nanolithography but there are major difficulties there.

"The challenge with photolithography is that it is rapidly approaching the resolution limits of light," said Xu. "In our approach, we shifted away from this 'top down' method of producing smaller features and instead utilized the advantages of a 'bottom up' approach. The beauty of the method we developed is that it draws on processes already in use in industry, so it will be very easy to incorporate into the production line with little cost."

There’s no doubt CCTV people are living in some seriously exciting times. With a combination of onboard video analysis, dual MJPEG and H.264 codecs, as well as 1TB non-volatile storage pods, the CCTV cameras of the future are going to be very powerful indeed.