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Atomic Scale Memory
maddugan writes "Technology Research News is reporting that researchers from the University of Wisconsin at Madison have put the theoretical to the test by using single silicon atoms to represent the 1s and 0s of computing. This is equivalent to storing the contents of 7,800 DVDs in one square inch of material."
Only half joking: Researchers at U.Michigan hope to
store up to 10 bits per atom, by using Rydberg states.
http://www.aip.org/enews/physnews/1999/split/pn
>:K
>;k
This isn't actually very useful : what we want is atomic scale logic gates, not data storage. In fact I'd venture to say that this technology is NOT what we will be using in the future for extremely dense memory. Why? Because its 2 dimensional and requires an independent readout head (that is MECHANICAL). Making it work anywhere but a vacuum may be impossible. (though that is not a real problem : making a disk drive that has an internal vacuum is quite feasible) A solution that is thousands, even millions of times faster would be a system that reads itself : i.e. a 3 dimensional array of logic gates to form a molecular version of ram. In addition, you could cram far more bits per gram of material used for the media. (I can't say per square inch because that would be misleading) In addition, storage capacity is not what our computers need more of : its performance (especially in accessing all those gigs of storage).
In 1959 Richard Feynman said that all the information accumulated in all the books in the world could theoretically fit in a cube 1/200th of an inch on a side.
You can read the transcipt of the speech from when he made that prediction.
Feynman worked on developing the atomic bomb, he won a nobel in physics and is known as much for his scientific research as for his story telling.
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When DVDs are burned and read, you don't simply read raw data off. The information is, of course, encoded. The DVD (and CD for that matter) specification says to use Reed-Solmon encoding. Saving the long math, RS encoding is about the most advanced error-correcting scheme that can be implemented in low-cost hardware today. By encoding data this way, your DVD (or CD) can become fairly scratched, but still play. RS protects against multiple-point errors. However, there is a price to pay - for every ~33k byte block on a DVD, almost 5K bytes are used in the parity checks for the DVD. See this file for more gritty details about DVDs. This means your 4.7GB DVD really holds about 5.48 GB of raw data.
Now, why is this relevant? Harddrives use their own error correcting schemes too. Manufacturers have the luxury of creating their own encoding systems since they're the ones that provide the read/write mechanisms. You can't pull the platter out of one harddrive and stick it in another. Hard drives typically use CRC (cyclic redundancy check) encoding schemes. I know you have all gotten CRC errors on a floppy way back when - that's what it stands for. Anyway, CRC is much less efficent when you compare the protected data to parity information ratios. While I wasn't able to pull the actual numbers from the Internet or my old math books, you can find a discussion and sample math here.
When you boil it down and relate all this information to our magical harddrive, the maximum usable density of the data would hover between 85%, or 6630 DVDs/in^2, to 60%, a measly 4680 DVDs/in^2, of the listed capacity. This is all assuming that the ideal lab conditions are maintained for a consumer level product.
As always, beware what the numbers tell you. However, if this can fly, then it would be an awesome step forward. Once you get Windows 2010 installed, you might even have a few Gig to play around with!