To many, holograms are either those silver pictures of William Shakespeare on your credit card or something off Star Trek. But the technology may finally move out of the realms of sci-fi novelty and into storage.
The demand for storage in the enterprise is increasing rapidly, as is the need for cheaper technology with more capacity. Until now, improvements made in magnetic storage technologies have met the mounting requirements, but some experts are suggesting that holographic storage could provide a cheaper solution.
The advantage of holographic storage is that unlike magnetic technologies, which store data in a two-dimensional plane using the magnetic coating on a disk platter, holographic technologies store data in three dimensions. As it is a three-dimensional technology, increasing the thickness can also increase the storage capacity of a disk.
Storing information in a hologram is just one aspect of a move towards making faster, more powerful computer systems that process data using light rather than electricity. In a holographic optical memory, information is recorded using two laser beams.
One carries data encoded in a pattern of light and dark regions, like the pixels of a monitor. The second, 'reference', beam traverses the first at right angles, and interference between the two beams produces a three-dimensional pattern of light and dark. This pattern is imprinted in a block of material that acts as the storage medium, rather as photographic film records the distribution of light and dark in a scene to which it is exposed.
The key point about a holographic memory is that numerous sets of data can be recorded into the same block of material, superimposed atop one another. Each set is recorded using a reference beam crossing the 'write' beam at a slightly different angle. It's like taking several photos on the same exposure but still being able to view each one individually.
Storage goes holographic
Some companies are trying to develop commercial holographic storage systems. Lucent launched a joint venture called InPhase Technologies, with storage firm Imation. InPhase will work on photopolymer and manufacturing technology that has been developed by the two parent companies to develop holographic data storage systems (HDSS).
These two partners have improved materials and systems technology enough to launch a business around it. It is claimed that the company has used DVD-developed lasers to reach storage densities of 300 gigabits per square inch and transfer rates of many tens of megabits per second.
InPhase's challenge involves technology that has been researched for more than 20 years, but which has yet to realise its promise. Lucent has said in the past that problems involving systems, materials and funding have delayed development over the years and prevented the technology's commercial fruition.
In addition, the technology has been overshadowed by swift advances in magnetic technology, which has achieved better-than-expected speed and capacity improvements by exceeding what were once thought to be its physical limits. At the same time, progress in holographic data storage (HDS) proved more difficult than imagined.
InPhase is not the only trying to turn HDS dreams into commercial reality. Its rivals include Holoplex, founded by Demetric Psaltis, a professor of electrical engineering at the California Institute of Technology. Also, IBM has invested considerably in holographic technology over the years, and was a major player in the US government-funded Holographic Data Storage System consortium in the mid-1990s, along with Rockwell Science Centre and Stanford University.
This consortium had managed to increase storage density and data rates beyond anything that was achieved before. IBM is still continuing research but is taking a wait-and-see approach to product development. It will sit on the sidelines and see whether the startups make the technology cost-effective before it enters the market.
Advanced system from Nasa
But some of the research projects on holographic storage point to what might be possible. Nasa, for example, has been working on an Advanced Holographic Memory system that would be capable of storing 1Tb of data and have a data transfer rate of up to 1Gb/s, with power consumption of just 0.01W/Gb. It would also require no moving parts. The power consumption alone could provide major benefits for firms, especially as power demands from more and more storage and hardware threaten to push power stations to the limits of their capacity.
However, all does not bode well for holographic technology. The US government, a long-time proponent of the potential of holographic systems, recently decided to stop investment in the technology. Last November, the US Defense Advanced Research Projects Agency (Darpa) cancelled all government funding of holographic storage research.
The advances already seen in holographic storage will boost the amount of information that can be stored on, for example, a DVD. However, price as well as capacity is of high importance for firms buying storage systems. The next couple of years will see huge increase in demand for storage, and more competition between vendors. This competition will hopefully result in lower prices all round and more storage whatever the technology.
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