Boffins invent 42GB DVD
A disc capacity to rival Blu-ray?
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, have – according to Google’s translation of a document released by the university department – discovered a way to multiply the amount of data stored on a DVD. The group also claims to be able to replicate the method for CDs.
Essentially, the team states that by changing the shape of the data-storage pits from having a flat bottom to one that's a V shape, each pit will be able to hold more data. Changing the horizontal orientation of the tip of the valley, alters the way light is reflected by the pit. As a result, pits no longer represent binary 1s and 0s, but a range of values, effectively allowing each to record a byte rather than a bit.
The upshot: individual discs could hold up to 42GB of data.
But before you go running off to the stationery store, it’s worth noting that the technology is essentially useless. That’s because current DVD machines aren’t designed to write or read disc data in such a way, so you'll need new hardware. And if you're buying new kit, why not get a Blu-ray drive and be done with it?
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.
So, whilst the Tohoku University researchers' idea may hold some merit, it’s probably a case of too little, too late. Unless they adapt it for blue-laser discs, of course...
COMMENTS
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...
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.
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?
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.
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).
