back to article Boffins invent 42GB DVD

Blank DVDs are a cheaper storage option than Blu-ray, but the HD format has greater capacity. However, Japanese storage scientists claim to have invented a method for storing up to 42GB onto a single DVD. Researchers from the Institute of Multidisciplinary Research for Advanced Materials, based in Japan’s Tohoku University, …


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  1. trevellyon

    yes but if the same technology was applied to blu-ray

    then blu-ray could hold 500Gb

  2. Anonymous Scotsman

    obvious in retrospect

    makes perfect sense, shame no-one cared when it could have made a difference.

    although, this could become a very effective workaround for the wibbly standard that is blu-ray, with all its content protection &c. Still, getting more bang out of mountains of (comparatively) dirt cheap dvds for crap that only has to be stored for a year or two would justify a mutant DVD±RW I'd say.

    but, naturally, no-one (except maybe philips) is going to pick it up since licensing/royalties lol etc cant concievably justify the expense .

  3. Sampler

    Couldn't you combine the two

    Had have even higher capacity Blu-Ray discs - of course with the instant incompatibilituy for all us "early adopters".

  4. Eddie Edwards

    Interesting fact

    An interesting fact is that current BluRay readers will accept multi-layer BluRays of the future without hardware modification (only firmware upgrade). So the drives are pretty future-proof and in theory support 2700GB or more.

    Phil Harrison told me that, and he should know, as he is God.

  5. James Pickett (Jp)

    Same Technique on BluRay?

    Does it follow that they could apply the same technique to BDs and multiply the capacity on those?

  6. Ed


    Combined with BluRay, surely you could get 250GB+ on a disk... And, I'd imagine the resolution of the rotation detection of each pit could be improved even further...

  7. Adam Foxton

    Would this work

    on Blu-Ray discs too?

    Going from a bit to a byte per pit = 8x increase in storage = 400GB per disc. And THAT is a huge amount of data rather than the relatively trifling 50GB of Blu-Ray standard which wouldn't even hold my entire Steam collection.

    With more accurate actuators and sensors could it be moved in 2 directions, giving an 8x8 grid, or 8 bytes per pit? At 3.2TB per disc this'd be pretty gosh darnded impressive.

  8. Matt Thornton


    Don't know anything about BR works, but can they apply the principle and make BR disks capable of holding, erm, reckoning SD 4.3gb -> 42gb ~ x10... 50gb x 10 = ~ 500gb?

  9. Anonymous Coward
    Anonymous Coward

    Increase Blu-Ray

    Seems to me the same technique could increase Blu-Ray capacity to somewhere around 400GB...

  10. Tim

    cant they not do the same to blu-ray?

    Surely they can do the same thing and up a standard blu-ray by the same multiple!

    Seems they tried to polish the proverbial turd with this research.

  11. rich
    Black Helicopters

    So use it in a Blu Ray

    Blu-ray works entirely the same way as a DVD only with a much smaller track pitch. Use your 42Gb DVD technology on a Blu-Ray and we can have 500GB on a disk - Thats probably just enough space for some civil servant to leave the countries Biometric Data, Credit Card Details and Inside Leg Measurements on the southern service to Brighton.. with just one disc. Briliant.

  12. Gary F

    Why not apply this idea to Blu-Ray?

    Instead of wasting their time to beef up an old technology why aren't they applying similar principles to Blu-Ray to create 500GB capacity per disc? Then suddenly a £10 Blu-Ray blank disc becomes rather good value!

    They could call it Blu-Ray-Plus and give/sell the rights to Sony so the 95% of people who don't have Blu-Ray yet will most likely be able to buy a "plus" player in the years to come instead.


    Why BluRay is rubbish...

    "Dual-layer Blu-ray Discs, although expensive, can already hold 50GB of data. And one retailer’s already punting a Blu-ray disc that it’s claimed will retain 25GB of data for up to 200 years."

    That's great... do I get to find out which half of my 50Gbs of data will get lost?

  14. JP Sistenich

    Has anyone thought about applying this to BluRay?

    Sorry, just thought I'd throw that in...

    The question surely should be how do you make a DVD RW out of this? Would be a bit silly if you had all this potential for storage, and then could only use it for pre-fab...

  15. Elmer Phud

    old tech?

    By the time they've got a product ready for the masses won't there be yet another type of high-density storage that isn't disc based?

    I though it was all getting smaller -- not carrying on with round bits of plastic.

  16. Ian Ferguson

    Not entirely useless

    Yes, you'd need a new drive - but (I presume) you could use existing DVD-R and CD-R media. These cost mere pennies compared to the £10ish for a single Blu-Ray disk - making this technology very cost-effective indeed.

    Being able to use an existing format as media is a fantastic idea - the problem with new formats is the media cost for early adopters, before mass production returns cost, but this approach effectively bypasses this major hurdle.

    However, this technology will never get off the ground. Why? Because all the manufacturers make so much money off shiny new media like Blu-Ray - CDs and DVDs are old hat. A shame really, as this would be a very efficient way forward.

  17. Mark

    What they don't tell you...

    Not compatible with any existing hardware on the market.

    Not compatible with any DVD duplication plants..

    Oh dear, a technology destined for the bin before it was even launched...

    If this had come out 5 years ago, it may have been great, but today it's worthless...

  18. Thomas

    Surely a read-only technology?

    As I understand it, real CDs, DVDs, etc, use pits and grooves so that the laser reflects to the expected spot or doesn't, producing 1s and 0s. Conversely, CD-Rs, CD-RWs and so on change the colour of the surface so it is still completely flat but laser light continues to either reflect or not.

    So surely this system isn't suitable for user-writable media?

  19. James Pickett (Jp)

    So if we're all on the same page here. . .

    . . . why didn't someone on the project think 'Hey, why not try this on a BluRay?' !!!!?

  20. Anonymous Coward
    Paris Hilton

    there's only one problem

    With's Sony. Make an industry-wide open non-drm standard which you can get from anyone and use any disc and then maybe I would think about it; especially if it was really reliable and long life.

    @rich & Inside Leg Measurements - Only if they have included if you wear left or wear right.....which I'm sure the gummint cares deeply about.

    You know she cares.

  21. Adrian
    Paris Hilton


    BluRay is 50 Gig. How is a 42 Gig DVD considered to have a bigger capacity ?

    Paris likes them big, and not just DVD's

  22. Tony Barnes

    lol @ same idea x 10....

    I would of thought that DVDs pitted at such an angle would be fine to master - but a comparative bitch to burn at home? Simple enough to stamp out shapes for a master copy and press away, but to create angled pits with lasers, at speed.... dunno.

    Trying to layer this would also create more headaches with refraction/angle issues I'd of thought.

    Still, very nice idea, as above, shame it's a bit late

  23. Richard Scratcher


    What we need is a series of holes that vary in depth to represent different data values and the the alignment of the holes could vary along the radius of the disc to represent yet more data values. In fact you wouldn't even need discrete holes, you could merge them into a single "groove", which would spiral in from the periphery to the centre. There might be some errors if the depth and alignment can't be set reliably, but for some media, such as music, it would be ideal and might add a "warmth" to the sound that makes it easier on the ear.

    Pass me my coat, I'm off to patent this idea. Mine's the jacket with the long sleeves that tie round the back.

  24. Anonymous Coward

    Slow comments?

    I am curious as to whether it took 1hr 20 for all these comments to get posted from the moment people started typing them or whether people just didn't read any of the previous comments... or even the last paragraph of the article.

  25. Anonymous Coward


    "effectively allowing each to record a byte rather than a bit"

    If that were true, each 'pit' would have to have 16 possible positions (8^2). The diagram only shows 5.

    Still, if the diagram is only a simplified representation of the mechanism then they can indeed represent whole bytes in a compressed fashion - very cool. Actually even if its only 5 positions, thats still signed half bytes.

    I seem to recall mulling over something of this nature in a somewhat stoned pub conversation some time ago - glad the concept has been proved!

  26. Mark Broadhurst

    Hey why not try this with HDDVD?

    Or some other already dead tech ?

    Still the big problem with blueray is the access time.

    I can see this having similar issues.

    So combining the two would be slow as hell.

  27. Boris Blank

    Re: Bytes?

    "Actually even if its only 5 positions, thats still signed half bytes."

    5 positions gives you 5 values, not 2^5(!!)

    You'd need 255 positions to represent a byte, with the 256th being "no pit".

  28. Highlander

    Good grief

    Ah, I still cannot believe some people. The Reg publishes a story about a novel way to increase the data density on an optical disc, in this case it was a DVD, though surely this method would work in most Optical media solutions.

    But instead of looking a that we have a dozen variants on "Should've used it in Blu Ray"; one drunken fool who thinks that because a retailer says a 25GB Blu-Ray will retain data for up to 200 years, blu-ray must be rubbish - forgetting of course that although Blu-Ray capacity goes to 50GB (dual layer disc) a single layer writable BluRay is 25GB, and that is undoubtedly what is being described.

    Then there is the inevitable HD-DVD comment by someone who still thinks that Blu Ray has a 'big problem' with access time. Slow access times compared to what exactly? The access times of a standard 2X Blu-Ray are ever bit as good as any consumer DVD player on the market and the data transfer rate is far higher. Unless you're doing random access on an optical disc(!?!?!?!) you care more about transfer rates than the kinds of seek times you worry about with a hard disc.

    And last, but not least, there's the I told you so post from someone who claims to have thought this idea up themselves, years ago, but you know, they never said anything because they were being nice.

    Business as usual in the Comments section

  29. Phil

    Why don't they

    try using this idea on BluRay

    I'm surprised no ones thought of this already?

  30. Charles Silver badge

    re: Bytes?

    Actually, for it to be properly classified as a byte, there has to be 2^8 (256) possible combinations. I don't think they've made the technology that precise as yet. The closest term is "nibble" (4 bits--16 possibilities).

    As for why use DVDs, I'm pretty sure this is just an experiment--a way to see if it can be done using well-available technology. Adopting the technology in blue-laser discs will probably be the next step--the smaller pits will require higher levels of precision in making those beveled pits.

  31. Anonymous Coward
    Anonymous Coward

    i scanned past most of the repetitive comments...

    ...but didn't anyone else read the last line in the article, suggesting they apply it to blu ray?

  32. Nexox Enigma


    """"effectively allowing each to record a byte rather than a bit"

    If that were true, each 'pit' would have to have 16 possible positions (8^2). The diagram only shows 5.

    Still, if the diagram is only a simplified representation of the mechanism then they can indeed represent whole bytes in a compressed fashion - very cool. Actually even if its only 5 positions, that's still signed half bytes."""

    You, Sir (or Madame) are a moron. A byte is 8 bits, which is not 8^2 (which would be 64, not 16) but rather 2^8, which is 256. Beyond your terrible math, you seem to think that the position count equals bit count, which is wrong, unless each pit can be in a combination of different orientations, and from what the article said, that's not how it works. Thus 5 positions would get you barely more than 2 bits, let alone whatever a signed half byte is. You should be barred from using the scientist icon.

    Plus, those are pictures for illustration. Would 256 little pictures be better than 5, for the purposes of sharing some research information?

    And to press CDs and DVDs I believe that they etch the bit pattern into a piece of glass. Have fun getting chemicals to selectively etch out angled pits, or even different depth holes

    I guess I'll just wait (a while) for realistic holographic discs.

  33. Mike Lovell

    I know

    Here's my thinking out the box idea, now I doubt it would have occurred to anyone reading the article - Certainly nobody would have posted a comment suggesting this - As it requires pretty abstract thought, but...

    Why don't we use this on BluRay

    tum-te-tum, won't bother reading any of the comments before this.

  34. Mad Hacker
    Jobs Horns

    Anyone remember bubble memory?

    So this is bubble memory 2.0 eh? That went over well.

  35. Richard

    Yes, you need new hardware but...

    You can make a DVD player for a bit more than what it costs now, but

    less than what it cost for the blue-ray player and have close to parity

    capacity wise. A good chunk of the price for the blanks use by blue-ray

    is for paying of licensing, not materials.

    So what you do is make a competing standard (shudder) but make it

    open source or close to it. Think of if it as a chance for Toshiba to get

    revenge. You make DVD's with one side using traditional and the other

    using the newer higher density version. People with old DVD's get to

    play normally, people with the advanced get HD. Blue-ray is still priced

    high enough that if someone came out with a player at around $150

    that did the upscaling for the regular DVD plus the HD, I think it would

    sell reasonably well. The two sided DVD would likely have to charge

    a small premium at first given you are recording on both sides, but

    since they can sell DVD's for $1 and still make money, I imagine it

    would not be THAT much more expensive.

    But the most important thing is, no LAME DRM. :-)

  36. b166er


    stop encouraging these optical people with your articles. Please instead encourage the Solid State people.

  37. Highlander


    Great, now, what do they do for the next 5 years while this technique transitions from the lab to production?


    Ooooh arent we all 1337 and stuff? Solid state presently requires two major changes. 1) 32GB of flash storage must cost literally pennies. 2) Internet infrastructure must cope with an order of magnitude more traffic than it currently does. A third change would be that High Capacity Internet would have to be both cheap and universal. Without univeral and cheap high capacity Internet, there really isn't much chance of anyone beyond a few technology activists and geeks regularly downloading truly HD content to solid state storage for playback any time in the short to mid term future. Long term, Solid state is the way to go.

    Blu-Ray and DVD are enough to tide us over until that long term future is actually here. I must say though, I am thoroughly sick of hearing anecdotal posts from a very small number of 'elite' consumers who have really, truly high speed broadband (at $150 or whatever a month). They typically blather on about their home theatre system and media server (no doubt a multi-terabyte monstrosity). These same people are utterly incapable of recognizing that the vast majority of people arent' like them, nor as fortunate with their ISPs. Not to mention the sheer cost of a well equiped media server with a terabyte or more of HDD. Of course the thing is 1TB = 20 Blu-Ray discs. How many DVDs have you got cluttering up your home? Imagine in a few years having that many Blu-Rays. How many TB will you need to store it all? What happens when (it's inevitable) that nice big HDD has a failure?

    This is why this whole solid state/download/home media server thing bugs me. As a solution it's techie, and it works (up to a point) which is good. However a consumer BD or DVD player is 1000 times easier to use. But as a techie solution it's about as friendly as a slap in the face when things go wrong. Not only that but it's expensive, and when it goes wrong it takes your entire movie/picture/music collection with it (don't ask for a multi-terabyte backup solution, they cost the earth).

    Until the infrastructure can handle it and flash media is an order of magnitude cheaper, and home media server hardware is simpler to use and more reliable, downloads are not the answer. Frankly until it get's to the point where everything is stored on flash cards, you won't catch me investing in it anyway. I don't want to be one hard disk head crash away from insanity.

  38. Brian Hall

    Byte Me!

    A "universal" RW machine that could handle/write-read CDs, DVDs, & BRs this way would be a gift to the storage world. All media with 8X the storage? I'd finally have to give up my HDDs, I guess. ;)

  39. Andreas
    Paris Hilton

    Now here's a novel idea...

    ... What if they applied the same technique to Blu-Ray Disc?

  40. Terry Doessel

    Hmm, interesting

    If you increase the posible values of each pit, then you also increase the chance of having an error reading it.

    a small scratch that would not cause a problem determining between a 0 or 1, could become a problem reading a 0-7...

  41. Anonymous Coward

    Isn't BluRay just another type of HD-DVD?

    I thought the big thing with BluRay was all the content protection. Its still just an optical disk but the fanboyz keep on talking as if its some kind of magic.

  42. Astarte

    Hard Sums?

    Maybe I've missed a point here in one or two of the replies. Whatever the specific carrier (HDD, CD, DVD, BR etc) rotating media using a single read head creates a serial data stream so to read a byte eight bits of data must pass the read head. If we're talking about traditional eight-bit bytes then each byte can represent a single value of between 0 and 255. I.e. there are eight bits each with one of two specific values hence the range of 2^8 discrete values. Some systems use ternary bits where each bit has one of three values (e.g. -1, 0 or +1) a byte would therefore offer 3^8 combinations i.e. zero to 6560. Extending this idea to give each bit one of 5 would give an eight-bit byte a range of 5^8 or 390,625 values. More realistically, using nibbles (four five-state bits) instead of bytes could be a practical compromise, each nibble would then have a value range of 5^4 or 625 discrete values.

    In conveniently approximate numbers a 50MB disc contains 400Mb (bits). As each byte on the original can only represent a value of between zero and 255 then a system based on Quintibits (my term) would be able to store about 1,500 times as much data (5^8 / 2^8). Using nibbles would reduce the ratio to about 50:1 (2^4 / 5^4) and would probably be more practicable (error detection/correction etc). Add dynamic compression and you’re well on your way to a lot of storage.

    It should be possible to either reduce the rotational speed and/or increase the bit-pitch and track-spacing to reduce cost and improve reliability.

    Using more than 5 states per bit could give far greater yields but then, why not go fuzzy or analogue and take it from there? We’ll be into realistic holographic storage someday – plus multi-spectrum. Look at what’s happening in fibre data technology. How many (writeable and detectable) attributes can be assigned to a spot on a disc? (Reflection angle - as in this case; pit depth; diameter; colour; polarisation; et al). Perhaps we will be writing discs with an inkjet printer one day. I know, why not print our data on paper then read it with a scanner? (A hint of sarcasm there I’m afraid.)

    In my defence I’ve never quite managed to suck eggs so perhaps someone’s Granny could teach me.

  43. Scott Millin
    Jobs Horns

    Stonger DRM using this?

    You obviously wouldn't be able to duplicate this format easily, no more burnable copies, so you could stamp them out and be fairly certain the only way to run the supplied content is to crack the hardware. If the musos wanted to implement it, they could protect the digital copy and only output an analog signal.(or HDCP digital).

  44. John F***ing Stepp

    Should have used this on the

    5 inch floppy.

    (because blue ray has already been taken; (taken and used more than a crack abusing street entrepreneur having a two for one sale.)

    I want a couple of terabytes; I need to mail myself to the future; the real future and not this pathetic emo nonsense that we are looking at now.

  45. Matthew

    I feel sorry for Sony

    They invent a media type, call it Blueray Disc or BD for short and everyone calls it Blu-Ray. If you mention you bought something on BD folk look at you blank.

    Still back on topic, who could have predicted the amount of storage possible on a 5" optical disc?

  46. John Stirling

    I was chatting about this exact idea

    in the pub with my friends a few years ago, but was too nice to do it then on DVD, but I must admit I think it would be better if someone applied it to Blueray Disc, or even Blu-Ray.

    One issue I would be concerned about though, is I would imagine it will negatively influence the seek times - much as is currently a problem with BD compared to HD-DVD. Or something I heard anyway.

    I would be interested to see whether the life of the data is longer than the 200 year half life quoted by Blue Ray where you get to keep exactly half of your 50 GB (that's 25Gb - or 2^38, or 38^2, I think they're the same) for 200 years.

    Actually, on an entirely different tangent, have they thought about applying this to Blu-Ray?

    - From the flogging a dead horse department.

  47. Anonymous Coward

    What is the ultimate question of life, the universe and everything???...

    How many GB can you fit on a DVD?

    Answer 42...

    I'll get my coat...

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