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Better Holographic Data Storage 110

Posted by emmett from the pretty-cool dept.
Pinlighter writes "Optical holographic data storage has the potential of providing better storage densities and access rates than the magnetic media used today. However, the technology has problems, mostly because the information tends to get a bit scrambled each time it is reread. According to the link, a group of Japanese scientists have now developed a material which is stable for hours and across multiple rereadings. The material also allows easy erasure (by UV light) and rewriting."
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Better Holographic Data Storage More

Better Holographic Data Storage

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  • Wow. If I wanted media that wasn't stable when you reread it, I'd go back to useing my 5 1/4" drive.

    kwsNI

  • AI (Score:1)

    by aozilla ( 133143 )

    the information tends to get a bit scrambled each time it is reread

    sounds great for AI purposes!

  • I am no expert at this, but maybe the continuous, analog nature of holograms causes a problem here?
    If you have a holographic picture, we usually have smooth surfaces; if you view a program as a picture, it looks (more or less) like randomly set pixels. Having a 3D representation is only going to make things worse.
    Of course the goal is to increase the precision of the holograms, which will solve this problem; but unlike transistors, holograms do not have the kind of inherent "noise immunity" that silicon memory chips have. There is still a long way until we have data crystals à la Babylon 5.

  • quite! but i do think this has a lot of potential, if they can get it to work. more storage space means more pr0n means less time downloading!
    ...dave

    (p.s. 'if i went around saying i was king just because some moistened bit lobbed a scimitar at me-- they'd put me away!')
  • I'm shocked that until now no one has said "Hey, Cool, we can have data storage like the Enterprise (NCC-1701D)!" And to think...you call yourselves geeks.
    --
  • No, it's an article about an actor. Don't think he's holographic, either, which is kind of a shame.

    Hey, trolls - haven't you got something *better* to do with your time than sit on slashdot?
  • it currently seems to have more in common with the B5 data crystal things. imo of course :)
  • Well, they figured out another step on the path, BUT:

    The materials they're talking about are hideously expensive to manufacture.. and I doubt their set-up is very fast at this point. I also have to wonder if they've started testing what normal electron flow, or thermal effects, to the material would cause in the way of intereference.

    But they are starting to use angled beams to layer information, which should make the overall construct small, so possibly feasable to systems needing huge storage capacity.. at least short term capacity.. I also have to wonder if the beam disturbs areas that it's just 'passing through' and not trying to read.. in that case I hope the IRS adpots this technology in the near future.. I can just imagine what wholesale data degredation would cause some 'interesting' activity..

  • Until you get down to about 10^-7m you can consider everything analogue. Memories have a continually varying number of electrons held in a capacitor. Its the thresholding of the charge that defines a 0 or a 1.

    You can do the same with holograms, "if the reflected intensity is >0.7 (relative intensity) its a 1, if its .3 its a 0".
  • IEEE [ieee.org]'s Spectrum magazine, which appears to not be online (!), has an article in the Feb. 2000 issue about using magnetic RAM — just when the reason it's called a "core dump" was fading into the distant past :')

    Apparently these new iron memories would change in one clock cycle, but would then hold the state. (I can't recall the exact details of how it works, it was too late when I read it last night.) I got the impression that it could be used like EEPROM or flash-EEPROM, except sufficiently fast and inexpensive to be used for main memory.

  • R&D (Score:1)

    by jdevore ( 148449 )
    I think that this technology holds great promise for the industry and though it is not at the level needed for the consumer market there is no reason to put it down. For kwsNI you are contradicting yourself. In one reply you say that companies should put money into R&D and not lawsuits then you come in and say you would not use a new technology even before it is out of the R&D stage. So please make up your mind...Are you for or against R&D. If you are really for R&D then be supportive of a new technology and if you are not then don't suggest that companies spend money on it. If everyone looked at a new technology like you did in your reply then there would not even be a internal combustible engine.
  • So I am a little confused. It appears holographic storage merely uses a material that has optical memory properties (the electrons move to the light) to record a hologram on. So what is the benifit of holographic storage.

    It would appear you could get just as high an information density using lasers not in any holographic projection system. So what is the benifit of holographic storage.
  • Is "Instable" the media of which Ender's communication devices were made?
  • i never saw or noticed the data crystals in B5, but of course i only watched the first couple of seasons.

    in my opinion, the cool thing about the isolinear circuitry in star trek was not the ODN (optical data network, i.e. fibre optics, how 21st century ;) conduits all over the place, but the fact that processing speed could be increased simply by applying more power to the processor. since all data was optical, the additional power was used to generate a stronger warp field, effectively raising the speed of light and making things faster.

    maybe such a principle will apply here...
  • Hmmm. Why not refresh it like dram?. Assuming you could refresh it reasonably fast and your computer doesn't crash.

    Ryan
  • Remember: HAL's storage was Holographic. Holographic Algorithmic Whatsit...
  • If I understand the article correctly, one wouldn't create a "picture" of the program per se. The article was pretty clear that adjusting the angle of one of the lasers exposes a new "track" (at least, that was my interpretation).

    So, for conceptual purposes, one can imagine the device functioning much like a CD with "stacked" tracks.

    Humans are pretty damn ingenious.

  • The article doesnt seem to make any mention of how much space these babies can hold. I recall them being very good storage per physical space but the last time I had heard about them was a few years ago(?) and magnetic storage has come a long way since then. Anyone got some details?

  • I did undergraduate research on iron-doped lithium niobate. While LiNb03 *could* be used to store data holographically, organic polymers do a much better job at lower cost.

    LiNb03 is fragile (it's a crystal, drop it and your data's dead) and very expensive to produce. The crystals are grown using the same? process as silicon but has a much more complex crystal structure and is much harder to produce consistent crystals of good quality). A crystal about 5 cm x 5 cm x 1 mm cost several hundred dollars.

  • Because in a CD-ROM, you'd read a pit. One-bit value. In holographic storage, that same little area that had one-bit could actually store (picking a magical number out of thin air) 32-bits, simply by adjusting the angle of read.

    Has the potential for enormous increases in storage capacity. I thought most of this was clear in the article.

  • That's "Ansible." It used phylotes for the communication medium (and, in a strange feat of Star Trek engineering skill, they have no clue what a phylote even is)

  • Re:Why is Holographic storage good? (Score:3)

    by Daeslin ( 95666 ) on Tuesday February 08, 2000 @06:40AM (#1295958) Homepage
    I wrote a paper on this way back in college, so this is coming mostly from memory (mine, not holographic), but here's some of the hightlights that excited me:

    1) Massive increases in storable data. I believe the example given was the contents of the entire library of congress on a 10 cm/side cube of data.

    2) Near ram access times. I believe the actual figure is something like 100 and some odd nanoseconds.

    3) AI like ability to perform similarity matches. Not only can you shine a reference beam in and get the data, you can also project the data in and get an echo of similar data elements reference beams. Hence, you could shine in a bitmap, and get back the indices (echos of reference beams actually) of the closest matching chuncks of data in storage. The closest matches produce the strongest echos. I believe the U.S. Army was investigating using this to spot tanks via video cameras. The applications are endless. You've forgotten the name of a song, merely hum a couple of bars into a mic, convert it to wave, submit it and find out that it's similar to a chunck of "Stairway to Heaven".

    4) Potentially cheap once all the manufacturing is worked out.
  • HAL is a secret publicity stunt, add one to each letter and you get: IBM
  • But if the very act of reading it scrambles it, youre screwed anyway. My understanding is that you could write 0xEF43 to a byte and a second later read it and it'd be 0xEF45, not (in this case) because of the time causing it to decay but because you read it.
    Sounds to me like we have in our hands a grand new invention in memory storage devices: WOM

  • Jello RAM (Score:4)

    by demaria ( 122790 ) on Tuesday February 08, 2000 @06:51AM (#1295962) Homepage
    Here's a project that some people are working on up here at Syracuse University.

    Jello RAM. :-) Okay, not exactly, but it's fun to call it that. A very small rectangular cube (about 0.5" by 0.5" by 1.5" or so) is filled with a protein substance suspended in a solution. It is primed by hitting the substance with a laser, and it denatures the protein. Then, a laser is shot through on an X plane, and a different laser hits on certain points on the Y plane. The protein is denatured where the two meet. This substance is a three dimensional memory system. You read back by a similar method, but with a lower power laser beam. The laser doesn't pass through the points that are denatured, and produces a grid of binary numbers essentially. Of course, the protein cube requires no power, so it's perserved when off. Imagine being able to take the ram out of one machine and put it in a different machine, without changing the contents.

    These small cubes can hold about 4 gigabytes of data, and last price I heard was $20 (the cubes are practically nothing. They're cheap to make. It's the read/write equipment that costs a bunch). It has decent access speeds, cheap, and very small.

    This is all very experimental lab stuff right now, so the size and speed can change. The goal is to make very cheap, small, random access memory. Might be good to replace tape drives. It's several years off though, but money keeps coming in and development continues. Should be nice stuff, keep on the lookout for it.

    I saw development stuff in use a year ago when touring that laboratory, so I reserve the right to be incorrect or inaccurate with some of the statements in this post. :-)

    Mike DeMaria
    It's the FBI, we're being raided!
    Quick, break out the spoons! Eat the evidence!
  • for some jerk to come along and say " THIS STORY HAS BEEN POSTED BEFORE " and whine and whine about it... the people that do this are total assholes and should be anally raped and tortured..

    on the other hand, Holographic memory is quite fascinating.,, a few years back i collected all the holographic images that I could find, European artists/technoists seem to love holograms... theres always been a big market for them in Amsterdam/Berlin..

    now if i could fsck that holographic nude Marylon Monroe, Id be much happy :)

  • lithium niobate (Score:1)

    by Anonymous Coward
    From what I remember of my university photonics course the most pressing problem with lithium niobate memory is the slow read/write cycle.

    doped lithium niobate can be "fixed" - made read only by baking for a few minutes, readback time is measured in seconds. The coolest thing about it is its ability to regenerate data from partial images, the classic demonstration is recording a line drawing of a cat. Feed in a picture of the cats tail, for example, and the whole image regenerates over the next few seconds.

    According to the lecturer it was operating as an optical neural net.

    memory structure is as follows:

    light in
    |
    |
    --#-----\
    | |
    \-----/

    where the # is the crystal & the \/'s are 45 degree mirrors. Memory works by forming a diffraction pattern where the beam crosses itself in the crystal. An image is superimposed on the beam and recorded inside.

    Lithium niobate is an electro optical material with a planar structure. Where there is a voltage across it its refractive index changes. The doping allows ions to sit in the material. These ions are disturbed by peaks in the diffraction pattern & get dislodged into other layers of the crystal, this provides the voltage necessary to modify the local refractive index & store the pattern.

    Baking the crystal fixes them in position.

    Too lazy to type any more.
  • Memory you can only write to once! YAYYYY no, really. If you are denaturing protiens and, say, an undenatured area is a 0 and a denatured area is a 1, since the denaturing process is generally a one-way street (and it'd take a lot to make be believe you can reliably put a protien back together with lasers), eventually all your data is going to be 11111111111111111. It's the same principle as burning a CD-R. & IANAS but I think the only group who would want to use this as a ROM storage device is the MPAA. It must be horribly difficult to get the protien stuff to last more than a few weeks before it starts to smell or degrade from exposure to light or what have you.
  • Memory you can only write to once! YAYYYY no, really. If you are denaturing protiens and, say, an undenatured area is a 0 and a denatured area is a 1, since the denaturing process is generally a one-way street (and it'd take a lot to make be believe you can reliably put a protien back together with lasers), eventually all your data is going to be 11111111111111111. It's the same principle as burning a CD-R.

    & IANAS but I think the only group who would want to use this as a ROM storage device is the MPAA. It must be horribly difficult to get the protien stuff to last more than a few weeks before it starts to smell or degrade from exposure to light or what have you.

  • The act of re-reading does not scramble data nor does a few seconds mean decay. That is why this story is of any interest at all.

    It says they "have now developed a material which is stable for hours and across multiple rereadings."

  • my grammar is horrible!
  • [wow, there are a lot of idiots posting today, not you, the ones that replyed to you]

    I think the point is to make it stable without consuming power. Your solution is fine if you want RAM like memory, but not if you are trying to get a bigger hard drive.
  • In the movie 2010 (brrr...) at least, HAL stood for Heuristic ALgorhythm (pardon spelling). But the movie was so bad in general that it could easily be different in the book.
  • Yeah, and you didn't put the apostrophe in the right place in your post, but do you see us wasting space complaining about it? Oh, I guess we do. Great discussion board we have here.
  • We've had WOM for years, it's called the printer. (It's WOM as far as the computer cares anyway.)
  • Well, to ask another way: Is the continuous nature of the magnetic medium of your hard drive a problem?

    Your hard drive is on the lowest level an analog device - that's why you can read data that has been overwritten using several times if you have good enough equipment. This implies that the magnetic head is writing to the disk at a great redundancy in both area and magnitude.

    There is no inherent "noise immunity" in the hard drive or your memory chips either, they have their own decay rates which are slow but existent.

    You can do the same with any analog device: just store your thing with large enough pixels and volume and it will stay readable for a long period of time (provided the material won't decay).

  • "Ansible" is the device, not the composition. What better material for instant communications than "Instable"? (Hey, if they can't spell well, we have to do something with their product...)
  • I am no expert at this, but maybe the continuous, analog nature of holograms causes a problem here?

    Holograms (in general - not too sure about those used for data storage) store information as the Fourier transform of the scene they're recording. This has two consequences:

    • A point of light is stored as a series of smooth fringes in the hologram
    • the fringes for a given point of light extend over the whole of the hologram
    So, the analog nature of a hologram isn't so much of a problem. Of course, the resolution of the hologram will limit the data storage capacity, as will the size of the hologram. However, if you lose half of your hologram, you don't lose half your data; your data is just twice as blurry (if that makes sense).

    Edric.

  • If the data density is as increased as everyone says it is, we can easily eliminate errors by compensating for them with hamming code. We already do it on CDs and tons of other types of data storage that has the possibility of loss.

    Esperandi
    Buy stock in vibrating mirrors!
  • I know what you're going to say, CDs are reliable ways to store data. And you're right. They're also unstable. So how do we take an unstable media and make it into a reliable data storage device? Hamming code. Complex error checking. Its a bit of overhead, but you don't have to worry about the instability and you still get some of the data density increase.

    Esperandi
    BTW, about CDs, if you scratch the "bottom", the CD will survive. If you scratch the label side, you're screwed, so quit laying them down label-side-down!
  • I think that write speed was also a big problem for holographic memory and that hasn't been addressed. The writing process is typically done using a photorefractive material and this means you shine light on it, set up an electric field and let the excited electrons diffuse trap states in the `dark' regions. This results in an index change that can be `read out' later. The problem is the diffusion time. I don't see how they can make that a very fast process, so while you'll get great read times, the writes are slow. Last time I, speed was more important to most people [intel.com] that size.
  • Sounds like this would allow them to get RAM into much smaller places if the bare parts of the iron modules they use (the ones that just hold one bit) are smaller than a dozen or so transistors, these could easily replace the latches used in memory now.

    Esperandi
    Up next: The hard drive of the future will be based on a rotary drum
  • If this is true and the "decay" is predictable, this is easy to fix. You want to store 0xEF43? Pass it thru a filter that turns it into something that when corrupted turns back into 0xEF43... then after you read it once, refresh the store.

    Of course if that doesn't work, error-checking code could easily make all of this possible.

    Esperandi
  • Please tell me they're gonna make this stuff look COOL when they produce them? I mean, harddrive could look cool, but instead they chose to hide them in a metal box inside the computer (they coulda mounted it in plexiglass and had it mount in the front face). I'm thinking of a tray that you can eject like a CD-ROM tray but has the cube with the lasers around it sitting right there, maybe even add some sort of fluorescence to the process so you can see "glitter" when the laser hits a denatured spot (or a non-denatured spot, wouldn't make much difference)...

    Oh, and make it an eerie green like the green used in The Tommyknockers movie..

    Esperandi
  • I think what the poster was really asking wasn't `Why is holographic storage better than CD's?', but `Why is holographic storage, better than storing a 3D image of the actual data you're encoding?' The answer to the first question is obvious, but its not clear why we should use holographic. I know of a San Diego company that is *not* using holography, but stores data like multilayer CD's. You should get the same amount of data, the only difference is the representation of it. I think the main advantage of a holographic memory is that is less sensative to defects in the media. The data is stored as a grating (redundantly throughout the whole media), so you can't just point to a spot and say that's the bit I just wrote. This comes at a cost, though because then you have to do holography. This is a no-brainer if you have 10K to spend on an optical table, but doing it on everyone's desktop is much harder. I don't know if it will ever be commercially feasible.
  • No, it is rewritable.

    Perhaps denatured isn't an accurate description. I'm not exactly sure of the specifics as I can't remember, but it does involve either a specific protein or organic creature (bacterial maybe).

    Whatever it is, the substance is rewritable and in a sealed container. Degradation is a valid concern, I don't know the status of that.

    Mike DeMaria
  • It looks cool in prototype form. :-)

    The protein cube does glow at the moment, due to the laser refracting. That's bad. :) But good. :) Details to work out, that's why it's still a lab technology.

    It wouldn't probably hurt to put some sort of LED below the block to make it glow. It's a purple looking substance.

    Mike DeMaria
  • WE 0WN J00!!!

    That would be "they", not "we". You are a spammer, not a troll.

    Trolls 0WN everyone, but they do so in an intelligent, creative fashion, not by mindlessly disrupting discussion. Trolls actually encourage discussion, in the form of luring those who think they are super-31337 into responding very strongly to an obviously fake post. It's an art form.

    It's hard. It takes effort, and intelligence.

    And this is why real trolls can't stand spammers: spammers keep good trolls, real efforts, incredibly funny, subtle masterpieces, from getting noticed.

    So don't glorify yourself quite yet. Write something good, funny, flamewar-provoking first. Pose as an unbelieveably clueless ex-lawyer marketing department RWM whining about the Imminent Death of Slashdot (tm), to combine a few of the more prominent troll themes. Or you could take the outright funniness troll method, and post the next "Star (as in hot young actress) Wars".

    But until then....
  • I never understood this. What good is a publicity stunt if it's secret?

  • It is so awesome that they have the technology to do this. Imagine, backing up several hard drives to one disk about the size of a 3.5" floppy, screw Iomega's zip drive, if this is market'ed well, we may have a new super floppy/tape replacement/keep up with your proccessor/use it as more virtual memory that is faster than real memory/holy shit OC-12's are going to get the're bandwith's worth in downloading/etc...
  • I remember reading an article in the New York times around ten years ago, talking about how holographic storage was going go be the Next Big Thing. They talked about 1-cm cubes holding a gigabyte (GASP!) of storage. Of course, this was when a 65 MB 5-1/4" hard drive was large. Hopefully we'll eventually see some actual holo storage technology in common use... eventually. I'd hate for this technology to become yet another of those things we always hear about but never get to have.

  • I have recently written a paper on this area for a photonics course. The inherent problems of 3D data storage are numerous to say the least. The only way currently to write the data is by way of laser, which also creates a problem of cross talk between the layers of the lattice structure of the recording medium. There is currently research being performed to eliminate this problem by utilising a dual-laser writing technique that would create only constructive interference at the position of recording.

    The other major problem is the type of laser used. A pulse laser writes and retrieves data faster, yet is known to damage the recording medium. The solution is to use a high-powered contiuous-wave laser, which is being looked into.

    The real decider in whether holographic memory is whether or not a certain compression of data can be reached. Off the top of my head I think it is somewhere around 10 megabits of data per square cm. Last I knew, I believe it was somewhere near 1 megabit per square cm. This is a really facinating topic, and I encourage all to look into it for themselves.

    Ciao.
    nahtanoj [mailto]

  • Photochromic storage has been around for a long time, and it still seems to have most of the problems it did in the 1960s, like slow writing rates and data slowly fading out. The write operation is a chemical reaction, so this is an inherently slow technology. Sounds like a marginal idea.

    Volumetric storage, where data is stored all through the volume rather than just on the surface, is a obvious idea that's been tried a few times but has never really worked. DVDs have a little of this, with several layers accessed by adjustable focusing. The coincident-beam laser scheme is attractive in theory, but requires beam-steering, which is mechanically messy. Still, mechanically messy concepts have been turned into mass-market technology before; look at the innards of a VCR.

    Stable, write-once volumetric storage might be useful as a backup and distribution medium. That may be a more promising direction than something that degrades with time.

    Corning Glass once built a computer display device using a photochromic plate for image storage. The plate was written with a UV CRT, erased with a bank of IR lamps, and read with a green light. It looked like a microfilm viewer, with rear projection. A few units were built and the idea dropped. This is one of the few products, other than photosensitive sunglasses, ever to use photochromic technology.

  • The potential storage density of holographic memories is 1000 Gbit/cm^3 (with green lasers). This limit comes from the wave-like nature of the light, requiring the structures to be greater than half its wavelenght. Typical wavelengths are in the visible (wavelength of green is around 530 nm) and tipical crystals are 1x1x1 cm^3 in size. It is possible to go to slightly shorter wavelenghts, but there the crystals start to absorb to much light (they are not transparent any more).

    The demonstrated storage density in photorefractive crystals is 10 Gbit/cm^3. The main reason for the reduced density is that neighbour holograms overwrite each other (called cross talk noise). Other causes are the light scattering (by crystal defects) and the so called self-focusing of the beam in these crystals.

    You may note that this is not so far beyond IBM's latest mini hardisks in PCMCIA and smaller devices, where there is even the controller included. The crystal memory needs a laser and some optics, which are not included in the volume above. So the memory density advantage is fading away (it's hard to compete with the computer industry), but there are other things that are much better, for example you can compare images very quickly (Tbit/s).

  • That's awesome! Format your holo-drive and get a suntan.

    Now I won't have to go outside to get rid of my pasty white complexion.

    /will
  • Just wait until mercury delay lines come back into vogue ;)
  • About the cost: LiNbO3 is grown similarly to silicium, so I don't think the cost would be a problem if large quantities are manufactured.

    About photopolymers: it is still impossible to make thick films (they are getting at 0.5 mm at present) and they are write once only (they need to be developed by UV light). You are interested in having bulk crystals instead of coated platters, because holograms can use the whole volume instead of some 2D layers as in HDs, DVDs and CDs. But photopolymers are still promising, the change of refractive index (i.e the efficincy) being much larger than in LiNbO3.

    The paper addresses tecnical problems, because it is based on the scientific paper given in its references, which reports nothing revolutionary (the photochromic effect was already reported by Germans 6 months ago).

  • I think not more than the analog nature of electric, electromagnetic and light signal is, the basic approach could be the same.
  • If the lifetime of these memory blocks were limited to a small number of reads before needing to be replaced/refreshed, I think this could be the next candiate for the MPAA's replacement for the DVD!

    The Other Nate
  • I make a PhD at ETHZ [www.ethz.ch] on this field. I don't think the NSA is worried about holographic storage, because it is still in research stage (what you have on the optical table is worth 100,000$) and because the storage densities won't be much higher than in HDs or in CD like media.

    But one thing you can do very efficiently with photorefractive crystals is comparing images (at some Terabit/s). This is because to calculate the correlation of two images (which tells you if two images are similar or where a smaller image is located in an image) you need fourier transform the images. Optically you can do a Fourier transformation very efficiently simply with a lens (in 10^-10 s = 100 ps): at the focus of the lens you have the Fourier transformation of the image and the time you need is just the time the light has to cover the distance of a few centimeters. A good image comparing system can be useful for military applications (guided missiles), security checking (fingerprints, face and voice recognition), person tracking, internet traffic filtering,... All dreams for the NSA, horror for me!

  • Startrek TNG? BAH! Kubrik and Clarke had those optical based storage devices inside HAL's noggin back in the 60's. Watch the disconnect scene in 2001 for an illustration.
  • Okay, I have heard this millions of times, and now my curiousity is piqued...

    Why is this so?

    Can you give me the explaination, or have you just heard this millions of times as I have?

    Laters
    Scandal

  • Well put, even if I may not neccessarily agree.

    Although I do see what you mean to some extent.

    Laters
    Scandal

  • Wow. If I wanted media that wasn't stable when you reread it, I'd go back to useing my 5 1/4" drive. You meant to say "3.5" drive" and not "5.25" drive," right? I have 5.25" floppies that are still readable with no errors after 15 years, but 3.5" floppies regularly go tits-up on me after just a few weeks. (I should probably still put the 15-year-old data on something more permanent, though...a single CD-R would more than likely hold all my Apple II stuff. Just need to get my GS to work with the CD-ROM drive I bought for it...)
  • Heard what part? I'll gladly answer, but I don't know what you're looking for ;) If you mean why scratching the label side screws the CD while scraping the underside doesn't hurt it, that's easy to explain. You see, they wanted CDs to last forever, so they put a huge (thinking to scale here ;) layer of protective material to guard against scratches. Only problem is that it caused the situation we have now, we have the label, then diretly on the other side of the label we've got the nickel substrate that the laser reflects off of. Then we hav ea bunch of protective layer. A lot of good that does when people are setting them down label-side-down all the time ;)

    Esperandi
  • Realizing that you reserved the right to be incorrect or inaccurate, I think there's something missing here. If the read laser cannot pass through a denatured protein, how does is read the points behind a denatured point. Perhaps one laser will pass through a denatured protien unless it is being "activated" somehow by being hit with another laser?
  • Well, the guy's page [syr.edu] lists some papers about it. Maybe it's something that'll work, maybe not, but they're well past the write-it-once stage.
  • You mean like Bacteriorhodepsin drives?

    (I mean, even Scientific American magazine had that one a few years ago.)

    See also: fluorescent multilayer, distructural polycodrone.

    Yay! Big words!

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