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Microholography Could Lead to 500 GB Discs
angrykeyboarder writes "Scientists have discovered a way to fit 500 GB of data onto DVD-sized discs. These discs would be created with a process called 'microholography, which combines multilayer storage of data with holographic imagery. From the article: 'Microholography allows data to be stored in three dimensions. The technology works by replacing the two-dimensional pit-land structures currently found on CDs and DVDs with microgratings, which are holographically induced using two laser beams. In other words, instead of recording to a series of bumps and pits like standard CDs, the new technology creates three-dimensional holographic grids that can be used for reading and writing data throughout the physical structure of the disc.'"
I blows me away how Sony missed out on the opportunity to use the MD format for data storage. It could have been the perfect 3 1/2 floppy drive replacement. How aggravating that they wasted the chance!
Life is not for the lazy.
Holographic Memories; Scientific American, November 1995, by Psaltis & Mok
It does make some sense to spin a disk rather than reorient the beam. But a solid crystal holographic storage device not only has lots of locations within itself to store collections of data, but can also be turned on a turntable and have the beam attack it from different directions, storing more data in the same place but at a different angle.
3D holographic storage design has another benefit -- it is self-searching via "reverse" holography. You shine a laser off a target and let it reflect to the memory, and out comes as many copies of the reference beam as their are stored data sets (with a realistic situation of most dissimilar results being buried in noise). Each beam is proportional to the strength of the reference beam according to the similarity of the dataset it came from. You can pick the strongest if you want to find the closest match, or you can statistically test the range of beam strengths to check for uniqueness of the target, or any number of things. The search process is virtually instantaneous, the speed of getting the result limited only by the speed of the measuring and calculating processes.
"I may be synthetic, but I'm not stupid." -- Bishop 341-B
The MD failed for the same reason the Iomega Zip and similar devices did: companies want to profit in every possible way from their inventions to the point that their patents prevent others from doing anything useful with the technology. This reduces the market until the technology dies and nobody can revive it due to those patents.
I have no data handy about it, but I'm pretty sure the same practice was not applied to hard disks and floppies, otherwise we'd be still saving data to punchcards.
On the other hand, at the rate available bandwidth is increasing, there is a much smaller need for portability. With a 4G mobile data network you may as well leave most of your data in a RAID array (where 'D' stands for whatever the densest cheap storage mechanism is) and stream what you need, with a few GBs of local cache. Latency is still going to be a problem, but WAN latency is still lower than optical disk latency in a lot of cases.
I am TheRaven on Soylent News
I don't know if I need a single DVD-sized disc to store 500GB of data. What I think would be cooler is if that space was made redundant and strewn all over the disc, so I could store maybe 100GB or so (still way lots) and have the peace of mind of knowing that an accidental scratch isn't likely to lose me anything.
Seen the Dvdisaster project? It uses some of the space (15 percent by default) as parity data at the image level to make a disc a lot more secure from scratching or other forms of what would otherwise cause data loss. Hell set it to 50 percent and you can pretty much guarantee the disc will be recoverable however badly you scratch it.
Something you might find interesting anyway.
It's easier to fight for one's principles than to live up to them.