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Mempile - Terabyte on a CD Wednesday, August 22, 2007 - Iddo Genuth Home >> Articles >> Storage
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Revolutionary new optical-storage technology currently under development will allow the equivalent of 250,000 high-quality MP3s or more than 115 DVD-quality movies and about 40 HD movies on a single CD-size medium. At 200 layers a disc, future versions of the technology will make it possible to store up to 5TB of data on one disc—the only question is, when will we find the time to watch all this content?
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Optical storage - a brief historyTFOT
Like the CD of the 1980s that introduced a revolution in audio, the DVD of the 1990s radically changed the video world, dramatically increasing the amount of data users could save and back up from their computers. In recent years, a demand for even higher-capacity media capable of supporting high-definition (HD) video content led to the development of two new optical media technologies: Blu-ray Disc (BD) and the High-Definition DVD (HD-DVD). Unlike CDs that use an infrared laser (780nm) and DVDs that use red laser (650 nm), both BD and HD-DVD use blue-violet laser (405 nm), which allows for a much higher density and capacity. HD-DVD has 15GBs on a single layer and 30GBs on a dual layer disc (HD-DVD RAM will have 20GB), while BD has 25GBs on a single layer and 50GBs on a dual layer. Although many attempts have been made to unite BD and HD-DVD into a single format, the rivalry is still ongoing to date, slowing the adoption rate and therefore increasing prices which are currently too high for most users. LG, Samsung, and other manufacturers are already promoting combo-players capable of supporting both HD-DVD and BD, but it seems the new formats still have a long way to go before becoming acceptable widespread standards. How optical media worksCDs, DVDs, and the current HD media have a number of physical similarities. Each uses a 1.2mm (4/100 inch) piece of clear polycarbonate plastic with microscopic bumps arranged as a single, continuous, spiral track of data. Optical media requires a player composed of a fast-spinning drive motor for spinning the media, a laser (infrared, red, or blue, depending on the player and media), and a tracking mechanism that moves the laser beam to follow the spiral track (with a resolution in the scale of submicrons). The function of the player is to focus the laser on the track of bumps. In a CD, the laser beam passes through the polycarbonate layer of the media and is reflected off the aluminum layer and hits an opto-electronic device that detects changes in light. Since the bumps in the media reflect light differently than the rest of the layer, the opto-electronic sensor detects that change in reflectivity and translates this difference into digital information (zeros and ones).
Another important technical change is the size of the laser spot which had to be reduced to read the ever smaller pits in the media. The original CD had a spot size of about 1.6 microns, which shrunk to 1.1 microns on a DVD—and even further in HD (0.62 micron in HD-DVD and 0.48 micron in Blu-ray). Besides the size of the data and reading apparatus, the data’s location inside the media also changed over time. While the original CD had only one layer located in the innermost part of the 1.2mm thick polycarbonate plastic (fairly close to the label), in a DVD (and HD-DVD) the data surface is located in the middle of the media. Blu-ray however is very different in this respect, locating its data surface on the opposite side of the label. Although each media type has a different location for its data surface, the overall volume taken up by the data inside the media is very small and the majority of space could be considered wasted.
Since the days of the first CDs, optical media increased its capacity by 75 times (from 650 MB in a CD to 50 GB in dual-layer Blu-ray media). However the demand for more storage space continues, and with ever larger hard drives now reaching capacities of 1TB and beyond, an appropriate next-generation optical media is in the making. Mempile’s TeraDisc technology
In late April 2007 the TFOT team visited the offices of Mempile, 20km Northwest of Jerusalem, Israel. Mempile, the company created by Alpert and a few of his colleagues in 2000, is now in advanced stages of developing its revolutionary optical technology, which we had a chance to see. When we first set our eyes on the see-through yellowish disc we were a bit surprised. Was the choice of color the idea of the PR department looking to draw attention to the new media, we inquired? The answer we received took us straight into the heart of Mempile's technology and made us realize that looks could very well be deceiving.
Overcoming this basic limitation of existing optical media is the goal Mempile set for itself, and the way to achieve it is by completely changing that way optical media works — starting from the material of which it is made. Mempile developed a special variant of the polymer polymethyl methacrylate (PMMA) known as ePMMA. After several years of trial and error, Mempile was able to develop this unique polymer, which it claims is almost entirely transparent to the specific wavelength of the laser used by its recorder/player. The yellowish color of the media is thus not a publicity stunt but the result of the special properties of the material used by Mempile. Using ePMMA, Mempile was able to create a media with about 200 virtual (i.e., created by the laser) layers, five microns apart, each containing approximately 5 GB of data. Although current prototypes are still in the 600–800GB per media range, Mempile is convinced that further optimization will enable it to reach its goal of 1 TB per 1.2mm disc in the very near future. But using specially designed polymers is just half the story. In order to make a media which could actually store all this data and effectively retrieve it, the old method of reading and writing on optical media had to be abandoned. Instead of the pits and flat surfaces representing zeros and ones, Mempile chose to implement a photochemical process, which happens when an ePMMA molecule is precisely illuminated by a red laser of a specific a wavelength.
In order to read data Mempile uses laser at a specific power which excites the chromophore in a particular layer of the disc. In order to record data, a stronger light is used which creates a different chemical reaction in the molecule. Mempile told TFOT that its technology can also be adapted to perform RW in the future, but market demand for such a product does not seem to be huge. According to Mempile their product should be very reliable, and different simulations and acceleration tests showed data lifetime of about 50 years. Although Mempile is currently planning to launch their first product using red laser (which is a more mature technology), moving to blue laser further down the road will possibly allow the technology to achieve up to 5 TB of data per disc.
Although this might seem like a long time to wait, there are some good reasons behind this decision. Besides the fact that Mempile developed an entirely new technology which is inherently different than that used by conventional CD/DVD/HD media, and hence bound to take longer to develop, the current market doesn’t seem ripe for such a revolution. In a time when 25/50GB media are still just a small percentage of the consumer market, bringing in 1 TB media doesn’t make sense from the point of view of most manufacturers. For that reason we shall probably see Mempile’s technology on the market just after HD media becomes mainstream.
Although many people find it hard to imagine the need for such space on a single disc, it is not inconceivable that by the time Mempile’s technology reaches the market, even higher-resolution video formats will start to appear, requiring hundreds of Gigabytes per hour, on entirely new display technologies, such as holographic displays, which could require even more storage space. Mempile InterviewTFOT recently interviewed Ortal Alpert, Mempile’s CTO, and Dr. Beth Erez, Mempile’s Chief Marketing Officer, to learn more about the company’s technology and future plans. Q: When and how was Mempile created? Q: Was there a Eureka! moment when reaching the idea or during the development stage? Q: How does the TeraDisc work and how is it different from existing optical technology? When a red laser is focused to a small spot inside the TeraDisc, we can choose if we probe the state of this material (reading , low power) or alter it (writing at higher power). This is very similar to the way a regular CDR works, except for the fact that this is now done in 3D. Q: What is nonlinear optics, how do you use it and how is it different than conventional optics used in CDs/DVDs/BRs, etc.? A simple example of a nonlinear phenomenon would be the weight of a steel ball compared to its radius — when the radius is about 5 cm you can pick it up and throw it away with one hand. If you increased the radius twice, you can probably pick it up with two hands, but you cannot throw it away very far, because now this is a rather large ball weighing about 33 Kg, if you further increase the radius by a factor of two, you will get a ball weighing 261 Kg, which means you need a forklift to pick it up. The process that Mempile uses to write and read data behaves much in the same way. It is called two-photon absorption, and behaves according to the radius of the beam to the minus-fourth power (sometimes even to the eighth power). Which means that when the beam is focused to a small radius, it is very easy for the photons to excite the chromophores, but when the radius of the beam increases even slightly, it becomes very improbable for two photons to be absorbed by a chromophore — so no writing or reading can occur. Q: Why did you choose red laser and not blue, and do you consider using blue laser in the future? 1.Red lasers are established technology, so red lasers are easier to come by at the needed powers and beam quality than blue ones. We chose 650nm wavelength as it allows for large enough capacity combined with a mature chemical and laser technology. 2. A terabyte capacity is enough to enter the market. I hope we will have a market for blue materials with an expected capacity of ~5 TB when we finish developing it. This is a very similar path to the path DVD took evolving into blue-laser-based devices (HD-DVD and Blu-ray) and takes similar transition times. Q: How are you able to direct two photons to a specific molecule in the disc so precisely without effecting nearby molecules? Q: How reliable will the TeraDisc be? Q: What do you see as your advantage over other high-capacity storage technologies (TDK’s 200GB BR disc, Inphase, etc.)? Q: What do you predict will be the main applications of the TeraDisc?
Due to the overwhelming worldwide reaction to TFOT's "Mempile - Terabyte on a CD" article and the numerous questions posted both here and on many other websites the company decided to grant us an additional Q&A published here for the first time and answering some of the questions raised by the readers. |
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great idea. as long as they make durable covers for the discs.. i dont mind losing 700mb or even 4.7gb But could you imagine losing your entire music movie photo collection because of a scratch? Great back up. |
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People always act like it's either the old and dating red laser or the new and too costly blue laser, but what about green lasers? those are a nice middle road, they are established technology but have a shorter wavelength than red, plus it's not too hard to develop carriers that respond to green I imagine. |
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| Why fart around with the red laser?... just go ahead and use the blue so we don't have to buy another drive that supports 5TB. Same crap with BR, if the plan is to support 4 layers, make 4 layer cap. 5X drive now. These companies need to quit breaking of crumbs, and deliver what they say they can do. We needed a 100 GB BR like 5 years ago (for storage). | |||
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Here's to finally having media with decent capacity. Sadly, it doesn't look like we're going to have anytime soon a transition like that from 1.44MB to 680MB. >i dont mind losing 700mb or even 4.7gb 680MB was a lot in 1996. 4.7GB wasn't as impressive in 2003, but still not something you'd want to lose. That's why you double backup and don't mistreat your media. :) >what about green lasers Maybe not a drastic enough change. Even BDs aren't so exciting compared with DVDs. >Why fart around with the red laser? You have to define your goals and reach them one at a time. Otherwise you risk losing more, if you manage to come thru at all. Even if it's possibly and easy to do something right away, I think companies have the right to profit more by doing incremental releases. Though, if there's competition, everybody's probably keeping on their toes. |
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| Make 2 copies. | |||
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I wish they would hurry up and start releasing these storage devices we keep hearing of. Ive currently got around 7TB of personal storage space... A bit much for DVDs. While my data is semisafe in RAID5, its not a proper backup solution. Bring on 5TB Disks... :D |
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| at 15 terabyes plus an additional half a terabyte per month, I need this technology now. in 3 years I will need 15+18= 33 Terabytes of storage minimum. thats about 8250 dvds or 33 terabyte discs. Think of the storage and disc organizational costs that can be saved. of course I will have two copies of everything. while the market for this product might seem small, each of those customers will buy a lot of discs. | |||
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| How long will it take to burn a 1TB disc? What's the seek speed? I'd like to see the performance stats when a prototype becomes available. Of course, in two years when this is available, SATA-3 will be the 'low-end' speed for HDDs. | |||
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Even if it's possibly and easy to do something right away, I think companies have the right to profit more by doing incremental releases. I don't mind companies making a proffit, but, as mentioned earlier, we've been hearing about these large storage solutions for years. Let's get on with it. Also, when I mentioned proffit is okay, I also mean I don't want to be taken to the cleaners either. Releasing a 1TB drive in 2009 (for example), and then releasing a 5TB drive in 2010 or 2011 seems like we're been taken advantage of to me. Especially when the blue laser is already an existing technology. |
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| A few months ago at the kurzweilai.net website there was a link that stated that Hitchi was coming out with Terabyte+ holographic disks. Why only cursory mention in the article, and why didn\'t the interviewer mention this in the interview with Alpert? I would have loved to have seen his opinion on the holographic disk, as well as his thoughts on a possible merger of the holographic technology with his technology (Keep in mind that I never even took Highschool physics, so WTF do I know?!). Still, I\'d love to know if Alpert and mempile even know what Hitachi is doing. Also I wonder why nobody has the strategy to come out with the best tech as fast as they possibly can, and simply dominate the market faster than everyone else does? Get the VC, and flood the market with low-cost 5 Terabyte disks! The only reason to fart around with the red laser seems to be \"versioning\" ...but that seems to me to underestimate things like the Hitachi holographic disks (due out in 2008 -I believe). | |||
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| Curious: how many times can the mempile Teradisk be rewritten? Will they offer versions that come hermetically sealed to avoid dust, scratches, etc? Can they be used to replace internal memory in a computer? Can http://www.optimal.org have advance copies of this hardware, since they are working the fastest towards strong general AI? :D Will this new technology give us higher-quality documentaries faster and faster? (Shifting the focus away from hardware limitations to the limits of individuals' creativity?) Is there a consideration for parallel processing guidlelines and architecture being automatically included in their read and write terabyte disk arrays? The more memory available, it seems to me (the lowest level of tech layman), the closer we are to the 10^14 cps needed to replicate "realtime" human brain function. If it's all about reading data fast, it would seem to me that parallelism and read speed would be very important. Is mempile going public/looking for investors? | |||
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| A similar concept was being developed in the late 90's by an Israli company with a Russian connection - Company called "Constellation 3d" symbol CDDD - it went under even though it had a working prototype. Be careful investing! | |||
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Mempile had some answers to questions here: http://www.tfot.info/news/41/follow-up-mempile-answers-your-que stions.html |
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| WOW! I can't wait for My MP Player :) | |||
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I am from PSGCAS of Tamil Nadu studying in BCA.you have made caparison of various cd's in diagramatic format, you can compare them with original ones. so it will be easy for us to understand. and also show about HD-DVD's also. |
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Our grandchildren will probably not be very surprised if the data is readable after 200 years, assuming they will still be able to find a working drive. Well yeah, assuming that our grandchildren live to be 150 years old to be in this scenario to begin with. |