Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

An Australian researcher has worked out how to store 1000TB on a CD

sciencealert.com.au

Post reply on HN
Print view View original

131–139 of 139 posts

Re: An Australian researcher has worked out how to store 1000TB on a CD

#131

Post by Someone »

ridgeguy wrote: post #85
Someone wrote: post #51

A big problem with spinning disks is that storage grows inversely with the area of the dots, while reading and writing speed grow inversely with the diameter of the dots. If you store 100 times as much data, all else being equal, time to write a full disk will be ten times as large. Ways around that are increasing rotation speed (been there, done that. There is little to gain here without making the disk a lot strong…

Stronger ≠ heavier. The parameter of interest is specific strength, which is the material's (ultimate tensile strength/density). I forget what the plastic in DVDs is, but it could probably be reinforced with carbon fibers (chopped, nanotubes, etc.) to give a useful increase in rotation speed.

You are right and I am not an structural engineer, but I understand that pure strength isn't the only limiting factor for disk; they start wobbling before they tear apart (http://superuser.com/questions/554717/will-there-ever-be-fas...). That, I think, is more a matter of thickness than of pure tensile strength. Barring the construction of hollow disks, that means heavier ones.

Also, now I think a bit more about it: in a 50-speed CD player or a 16-speed DVD player, the edge of the disk moves at about half the speed of sound. Doubling rotation speed would push it over the sound barrier. I guess it would take quite a bit of research to make a CD/DVD/BlueRay player that will work fine at those speeds (a way around that is to make the disk smaller. That would be an option for a disk with the storage density discussed here, but it wouldn't win you more than a factor of four or so, at most)

Re: An Australian researcher has worked out how to store 1000TB on a CD

#132

Post by JoeAltmaier »

Someone wrote: post #131
ridgeguy wrote: post #85

Earlier quoted context omitted.

Stronger ≠ heavier. The parameter of interest is specific strength, which is the material's (ultimate tensile strength/density). I forget what the plastic in DVDs is, but it could probably be reinforced with carbon fibers (chopped, nanotubes, etc.) to give a useful increase in rotation speed.

You are right and I am not an structural engineer, but I understand that pure strength isn't the only limiting factor for disk; they start wobbling before they tear apart ( http://superuser.com/questions/554717/will-there-ever-be-fas... ). That, I think, is more a matter of thickness than of pure tensile strength. Barring the construction of hollow disks, that means heavier ones. Also, now I think a bit more about it…

How about, give up spinning it. Steer the laser, perhaps using phased diffraction patterns, and scan the disk with weightless light?

Re: An Australian researcher has worked out how to store 1000TB on a CD

#133

Post by harwoodr »

tobylane wrote: post #127
harwoodr wrote: post #125

Earlier quoted context omitted.

Really? Assuming that the rotation speed is the same for a normal disk and this denser format, wouldn't said laser be moving over 250,000 times as much data in the same time period? At 1X speed, a DVD's data rate is about 11Mbit/s - so at 250,000 times the density, isn't it safe to assume a theoretical data rate of 2.75Tbit/s? Of course, pushing that much data at that rate is another problem... If my assumptions are…

52x speed has been the limit for a long time because the outside edge of the CD gets to speeds where it could damage itself. I guess it would need a cushion, like a nearly applied (car/bike) disc brake.

Okay - but I'm not talking about changing the rotational speed.

Re: An Australian researcher has worked out how to store 1000TB on a CD

#134

Post by kedean »

uncoder0 wrote: post #129
kedean wrote: post #55

Earlier quoted context omitted.

I'm skeptical that this won't be extremely fragile, physically. With details that small, the slightest scratch could erase large swaths of data.

http://www.mdisc.com/ or similar. There are tons of options for archival quality backup media. If the data is very important make a few copies and leave them in airtight cases if you'd like in different geographical locations.

Sure you could use an entirely different storage medium for backups, that's not my point. I'm saying that if someone happens to drop the disc on a carpet, that could be enough to erase big portions of data. It's not about losing whats on the disc, it's about the fragility of the media itself. I don't know much about the tech being used, but I could see it bordering on volatile if they're embedding that much information, and volatile storage isn't very useful unless its extremely fast.

Who's going to store data on something that will erase portions of itself when dropped? Consumers won't, because they won't know what to do when their 50,000 movies suddenly start skipping ten minute chunks. Scientists won't use it because they want strong guarantees on retrievability, and won't want to bother with stringent protocols on handling the media when other options exist. Logging systems might have a use for it, if they can stand potentially losing big chunks of data.

Re: An Australian researcher has worked out how to store 1000TB on a CD

#135

Post by TheLoneWolfling »

harwoodr wrote: post #125
NKCSS wrote: post #99

Earlier quoted context omitted.

You are forgetting that the speed at which optical drives can be written is bound by the rotation speed. If you have a single laser of this type and mount it in a traditional drive as we know, it would take over a year to write a single disk :) Still lots to do :)

Really? Assuming that the rotation speed is the same for a normal disk and this denser format, wouldn't said laser be moving over 250,000 times as much data in the same time period? At 1X speed, a DVD's data rate is about 11Mbit/s - so at 250,000 times the density, isn't it safe to assume a theoretical data rate of 2.75Tbit/s? Of course, pushing that much data at that rate is another problem... If my assumptions are…

You're forgetting the square-cube law. Or rather, in this case the linear-square law. Think of each bit as a square, with side length 1/n. Oversimplifying, but the basic principle is there.

The total amount of data the laser goes over in a second is proportional to n - because it's related to how long the laser takes to get from one edge of the square the the other edge. But the total amount of information stored goes up as n^2 - it's related to the area of the square.

Or: to put it another way, the number of tracks also goes up when data density increases.

(This also happens with hard drives over time. Recent hard drives take a lot longer to read or write the entire drive than older ones. See http://tylermuth.wordpress.com/2011/11/02/a-little-hard-driv... for example.)

Re: An Australian researcher has worked out how to store 1000TB on a CD

#136

Post by saeguaiga »

Oh great, another 1024-bit daisy-chained medium with a 20MB UeFI boot partition. We have watched this way too long and it was dragging us down...(cough)

Oops, accidentally implemented as a medium-hash CAMFS in disused packaging-and-optronics 45nm fab. Please write test, mind 5W limit if retaining cyano/pyridene dye in media.

Re: An Australian researcher has worked out how to store 1000TB on a CD

#137

Post by saeguaiga »

kedean wrote: post #55
krapp wrote: post #33

Earlier quoted context omitted.

"the internet" is a more fragile medium than a disk, that's why. High-density, cheap, persistent data storage is critical to make sure that most of the cultural expressions of the last few generations don't vanish into a black hole sooner than later. It's our version of ancient Babylon's cuneiforms etched in wet clay. Just imagine how much crap Jason Scott could fit into a storage container with these. A lot of crap.…

I'm skeptical that this won't be extremely fragile, physically. With details that small, the slightest scratch could erase large swaths of data.

Yeah, taking it into space or mining (WiMPs) would wreck plenty. You have to like the ECC you're on. you're on. you're on...

How often were you going to swap discs? When you got SESSION COUNT EXCEEDED, or UDF timeouts? Every time you give contact info...'and here is a capsule intelligence of things you may wish to contact me about in the next 15 years...but just call.'

Skip most of the spinning and size, put it in a fat SIM card, and have recovery pipelines (cleanroom et al) for failures. If you throw down for the 8TB (not really 8TiB) multiplatter +9 Fondleslab Of Regret maybe you can throw in the service premium to go visit the one retailer the future holds for us, do key exchanges, and have them print out a scan of peak versions of your besties, or let you write Abnormal_brain on the top with a marker?

Re: An Australian researcher has worked out how to store 1000TB on a CD

#139

Post by eru »

uncoder0 wrote: post #130
eru wrote: post #96

Earlier quoted context omitted.

It used to be Startup News.

Huh, didn't know that was the original name. I personally prefer the Hacker New moniker. I imagine 'Startup News' was just a working title for the project as it was only kept for ~7 months.

I reckon there was only so much you can read about startups on the web before it gets boring. (I certainly had that impression at the end of that phase.)
Post reply on HN