28 Jul 10
http://www.photonics.com/Article.aspx?AID=43195&refer=weeklyNewsletter&utm_source=weeklyNewsletter_2010_07_28&utm_medium=email&utm_campaign=weeklyNewsletter
It says the laser is a 405 nm wavelength but 100 WATTS with 3 picosecond pulses and a prf of 1 ghz, 1 billion pulses per second to allow the creation of disks with 20 times the storage of present day blu-rays.
I want one of those laser! Apparently they are relatively cheap also. I wonder if it could burst a balloon or light a match? 3 picoseconds is not a long time but a 3 ps pulse at a 1 ghz rate means the average power is still over 300 milliwatts, not something to sneeze at!
I'll bet it could be used for that mosquito killer laser we read about a few weeks ago!
29 Jul 10
Originally posted by sonhouseWould you need a similar laser to read the disks?
It says the laser is a 405 nm wavelength but 100 WATTS with 3 picosecond pulses and a prf of 1 ghz, 1 billion pulses per second to allow the creation of disks with 20 times the storage of present day blu-rays.
Though I guess anything better than current blue ray capacity is not really of any use to the movie industry (as they would be hard pressed to sell you 20 HD movies at once).
It would be wonderful for backup purposes, but the market is probably too small.
I'm still waiting for laser storage to go truly 3D, then it can finally take over from the magnetic hard disk.
29 Jul 10
Originally posted by twhiteheadEven if it goes 3D, by which I assume you mean multiple layers so if one layer does 1 terabyte, then 10 layers and you are into some serious storage. This may be true but optical drives can't go anything like 7 or 10 K rpm so they are intrinsically slower drives.
Would you need a similar laser to read the disks?
Though I guess anything better than current blue ray capacity is not really of any use to the movie industry (as they would be hard pressed to sell you 20 HD movies at once).
It would be wonderful for backup purposes, but the market is probably too small.
I'm still waiting for laser storage to go truly 3D, then it can finally take over from the magnetic hard disk.
I don't see optical drives competing with mags any time soon. They keep improving both optical and magnetic drives but so far mags win in total storage and speed.
30 Jul 10
Originally posted by sonhouseIt is probably not possible, but I was thinking of vertical data density similar to the current horizontal density, so a 1 cm thick disk could store something like 1000 times what a current disk does (and read maybe 100 times faster, as it would mostly be the laser refocusing, not the disk moving.)
Even if it goes 3D, by which I assume you mean multiple layers so if one layer does 1 terabyte, then 10 layers and you are into some serious storage. This may be true but optical drives can't go anything like 7 or 10 K rpm so they are intrinsically slower drives.
I don't see optical drives competing with mags any time soon. They keep improving both optical and magnetic drives but so far mags win in total storage and speed.
Also an optical drives speed limit is largely due to the cheap media and the fact that you can swap the disks and store them separately. They tend to be slightly unbalanced and will vibrate or shatter at higher speeds.
If however the technology was placed into a closed drive with a strong metal support layer in the disk, much higher speeds could be obtained.
It would presumably also be possible to put several double sided disks in one unit with multiple lasers.
My main concern would be that the market these days is for laptop size drives and I don't think optical can scale down that well.
And finally, I was also thinking along the lines of a tape drive equivalent for backup. In that case it is capacity and cheap changeable media that counts rather than speed.
I would like to backup my whole hard disk occasionally, but DVD just doesn't have the capacity to do that.
30 Jul 10
1 edit
Originally posted by twhiteheadAren't you thinking 1 mm thick disk? 1 cm is like a half inch. Also, what would you gain duplicating the technology with optical components vs magnetic components? The track finding system would be identical, there would have to be a mechanism for swinging a laser reflector back and forth, it would even be more complicated because it would have to have several reflective surfaces to guide a laser beam back and forth to it's laser/detector.
It is probably not possible, but I was thinking of vertical data density similar to the current horizontal density, so a 1 cm thick disk could store something like 1000 times what a current disk does (and read maybe 100 times faster, as it would mostly be the laser refocusing, not the disk moving.)
Also an optical drives speed limit is largely due to t to backup my whole hard disk occasionally, but DVD just doesn't have the capacity to do that.
The way it is done in a DVD or any other optical drive is for the whole lens assembly to drive back and forth radially from center to edge of the media. It would be very difficult to greatly increase the speed of changing tracks like in a HD, which uses a very light swing arm and can go thousands of swings per second. Try that with a blu ray. Besides, the whole laser and lens assembly has to be on the spiral drive assembly. They would have to completely redesign that portion of a drive to make it as fast as a magnetic drive.
They would by definition, to lower the mass of the moving parts, to get the lens and laser off the actual spiral or swing mechanism, mirrors or some such to guide the light back to lasers and detectors.
Maybe they could (are actually) developing nanosized lasers and detectors to be on the swing arm mechanism. One other problem I see with a swing arm mechanism like in a magnetic drive, if the storage media depended on phase relationships with the laser, the phase angle would shift from inner to outer track, further complicating the optical path.
At least with magnetics, there is one head to both read and write in the same unit and they are getting so small as to be almost invisible to the naked eye and so a very small mass so a swing arm can go thousands of excursions per second.
I don't see any advantage of duplicating a magnetic HD with optical components. They are already at 2 terabytes for a 3.5 inch drive and 500 gigs for a 2.5 inch laptop drive.
The other technologies like flash drives have a limit as to the number of write and read cycles, maybe 100,000 such cycles and the unit is mostly dead or beyond the capability of error correcting codes to fix. I think they don't correct more than 2 bad bits in a single byte right now and they could up that to 3 or 4 dead bits at the cost of making longer byte strings but then you start defeating the purpose of the greater capacity of the drives.
31 Jul 10
Originally posted by sonhousewould welding goggles filter that wavelength out?
http://www.photonics.com/Article.aspx?AID=43195&refer=weeklyNewsletter&utm_source=weeklyNewsletter_2010_07_28&utm_medium=email&utm_campaign=weeklyNewsletter
It says the laser is a 405 nm wavelength but 100 WATTS with 3 picosecond pulses and a prf of 1 ghz, 1 billion pulses per second to allow the creation of disks with 20 times the storage of present day ...[text shortened]... at!
I'll bet it could be used for that mosquito killer laser we read about a few weeks ago!
31 Jul 10
Originally posted by zeeblebotI'm sure it would, however, if left pulsing at a 1 ghz rate, it might drill right through it in short order! Maybe not, but it would be an interesting experiment. I would not want to wear one for that experiment however!
would welding goggles filter that wavelength out?
In answer to the question about whether the same laser would be used to read the disk data, yes it would, same laser but lower power, high power to cause the phase changes on the media and lower power pulse to read which state the media is in, biphase, one phase being more reflective than the other so you get 1's and 0's. With the appropriate error correcting codes of course.
31 Jul 10
Originally posted by sonhouseI was more interested in whether the same laser would be required
In answer to the question about whether the same laser would be used to read the disk data, yes it would, same laser but lower power, high power to cause the phase changes on the media and lower power pulse to read which state the media is in, biphase, one phase being more reflective than the other so you get 1's and 0's. With the appropriate error correcting codes of course.
ie could the DVD makers have the latest technology lasers and create high capacity disks whilst the rest of us read the disks in our older technology blue ray drives (with modifications of course).
31 Jul 10
Originally posted by twhiteheadI think not. The problem is to get 20X the density, if you do the square root, each track would have to be about 1/5th the diameter of the old one and spaced much closer together. There would be 20 times the data, so a regular blu ray would not be able to jump from track to track, they couldn't track at all. Like an old time record player, a 78 rpm job trying to play a more modern vinyl 33 rpm record with much closer grooves.
I was more interested in whether the same laser would be [b]required
ie could the DVD makers have the latest technology lasers and create high capacity disks whilst the rest of us read the disks in our older technology blue ray drives (with modifications of course).[/b]
I remember as a kid my old man actually trying that🙂 He had purchased a Lowrey organ and it came with some instructional records, he didn't know any better, and put them on his 78 rpm ancient player. Well, it was instructive all right. I was watching as he did that, just wanted to see what would happen. What happened was the old 78 needle made new 78 style grooves and the record started turning white where the grooves dug into the vinyl🙂 It was a bit on the funny side!
01 Aug 10
Originally posted by sonhouseNo, I really did mean 1cm. I was thinking of true 3D storage.
Aren't you thinking 1 mm thick disk? 1 cm is like a half inch.
Current technology can store multiple layers (most movie DVDs are dual layer). I believe more layers have been achieved but not generally used.
What I don't know is how the drive changes layers. Does the laser have to physically move, or can the layers be read by refocusing the laser by some faster method?
I was thinking of having something like 1000 layers so as to dramatically increase storage capacity whilst also increasing the amount of data per track thus increasing the data read per laser movement from track to track thus increasing potential reading speed.
I do realize it would never compete with magnetic storage, but it might be a better option for backup.
01 Aug 10
1 edit
Originally posted by twhiteheadI think 1000 layers right now is out of the question. They can do maybe 10 layers but to have a 1cm thick disk, the mass would lead to run out problems, which I saw up close and personal on a HD drive manufacturing line in Scottsdale, they required run-out (disk wobble) to be something like 50 microinches (just over one micron) and that is with a very thin glass disk. The rpms have to be very stable as well as the wobble to allow reliable tracking.
No, I really did mean 1cm. I was thinking of true 3D storage.
Current technology can store multiple layers (most movie DVDs are dual layer). I believe more layers have been achieved but not generally used.
What I don't know is how the drive changes layers. Does the laser have to physically move, or can the layers be read by refocusing the laser by some ...[text shortened]... alize it would never compete with magnetic storage, but it might be a better option for backup.
With more thickness comes more mass and more stress on bearings. I think such a disk would wobble too much and take a much larger drive motor in an era where engineers are trying to reduce power consumption, not increase it.
It would take much stronger bearings, all possible of course but the resulting device would be a lot heavier, consume a lot more power and probably be less reliable.
It would still have to spin a few thousand RPM at least to get any kind of speed unless there were 1000 lasers tuned to each layer simultaneously. I don't think that is going to happen either.
They can get a few layers now, say 4 max but it still uses one laser and therefore has to have a refocus assembly to get the focal point from one layer to another. Still with this new technology, 1 terabyte per layer is one heck of a lot of storage. Double layer goes to 2 terabytes, etc. Even one layer would be a serious amount of storage.
01 Aug 10
Originally posted by sonhouseYes I can see that the new laser is the way to go. Finally I will be able to back up my whole hard disk. But then again, by the time I actually have one of these new lasers, my hard disk will be 100 terabytes.
They can get a few layers now, say 4 max but it still uses one laser and therefore has to have a refocus assembly to get the focal point from one layer to another. Still with this new technology, 1 terabyte per layer is one heck of a lot of storage. Double layer goes to 2 terabytes, etc. Even one layer would be a serious amount of storage.
01 Aug 10
Having looked it up, I see I may not be so far off:
http://en.wikipedia.org/wiki/3D_optical_data_storage
Go down to commercial development
The record so far seems to be 200 layers.
You may also find these interesting:
http://en.wikipedia.org/wiki/5D_DVD
http://en.wikipedia.org/wiki/3D_optical_data_storage
http://en.wikipedia.org/wiki/Holographic_Versatile_Disc
They were talking about 8 layers on blue ray discs back in 2007:
http://wesleytech.com/200gb-blu-ray-disc-with-8-layers-developed-by-hitachi/212/
01 Aug 10
1 edit
Originally posted by twhiteheadGood grief! 1 PETAbyte of storage. I would like to see that! 1000 Terabytes, 1,000,000 gigabytes! A billion megabytes. NASA could use that level of storage, they are getting gigabytes per day of data, they must be single handedly supporting the HD industry!
Having looked it up, I see I may not be so far off:
http://en.wikipedia.org/wiki/3D_optical_data_storage
Go down to commercial development
The record so far seems to be 200 layers.
You may also find these interesting:
http://en.wikipedia.org/wiki/5D_DVD
http://en.wikipedia.org/wiki/3D_optical_data_storage
http://en.wikipedia.org/wiki/Holographi ...[text shortened]... back in 2007:
http://wesleytech.com/200gb-blu-ray-disc-with-8-layers-developed-by-hitachi/212/
It's too bad all those optical technologies are only good for 10 years of storage, since atmosphere gets in between the layers eventually and destroys the media.
All the movies ever made in a handful of disks!