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Magnetic and Optically read disk

A cd with magnetic information as well.
  [vote for,

Imagine storing data onto a CD/ DVD without actually having to use a CD/ DVD burner. You basically take the same optically read CD or DVD that you currently have and put a magnetic disk inside it so you could write a small amount of information on it and read that information back. You would have the optical tracks above the magnetic disk since you cant read optical tracks through a magnetic disk.

This could be good for music cds because the disk could store data on the magnetic section. The magnetic section storage could store various things such as track order and when the disk is coppied and how many times the disk is coppied for copyright protection. The magnetic storage section of the disk could also be used on DVDs to store where you are at on the DVD even if you pop it out of the player. This is a problem I see with current DVD systems is that if you pop the disk out of the player you loose your spot unlike VHS tapes were.

Another application is that you could just simply hold more information on a CD since you'd have magnetic information stored as well.

As well you could save video game information on video game DVD roms. Instead of having a hard drive like MS XBOX or expensive memory cards like Sony PS2 you could just save game data to the disk.

JoeLounsbury, Nov 11 2003

Google Search for "+magneto-optical +storage" http://www.google.c...-optical+%2Bstorage
About 83,600 hits. Same idea, different technology. [phoenix, Oct 04 2004]

Magneto-Optical Storage Systems (fourth link from Google search above) http://www.usbyte.c...ommon/MOsystems.htm
"The MO systems include basic principles of both magnetic and optical storage systems: MO systems write magnetically (with thermal assist) and read optically." [phoenix, Oct 04 2004]

DataPlay http://www.dataplay.com/
Creators of a small disk which I have never seen anywhere but the web. [st3f, Oct 04 2004]


       A word to the wise, Joe - the Halfbakery isn't just about having ideas, it's also (mostly) about sharing them. I'm sure all your ideas make sense inside your own head; you just need to try a little harder to make them make sense in other people's.   

       I do try, but half the time your posts are just inpenetrable. I know there's an idea there, but the way you word things just doesn't bring it out.
lostdog, Nov 11 2003

       Well, I think it makes perfect sense.   

       As for usefulness, I suppose you could use it to add track names or lyrics to CDs after burning...   

       The amount of data you could store magnetically would be a few percent of the capacity of a CD.   

       Of course, in Europe it's common to use Magneto Optical systems.   

       They were first introduced about the time Steve Jobs developed the NEXT computer. A laser heats a spot on the disk, which when hot can be written to magnetically, but when cool can't be changed.   

       We don't use them much in the USA 'cause they're slower.
Jkirk3279, Nov 12 2003

       Problem is that the read/write head has to fly SO close to a magnetic platter that putting a layer of anything on top of it renders the whole thing useless.   

       The data layer of a CD resides at the top of the CD, while the entire bottom is clear plastic--that's most of the thickness of the CD. That's about 1.2 millimeters of plastic. A little research gives a figure of 12 *nanometers* for the glide height of a drive head. So you're blocked by a piece of plastic 100,000 times too thick to read through.   

       No workie.
darksasami, Nov 12 2003

       Except now you've got this magical transparent ferrous material exposed to the open air where people can touch it. Having manufactured hard drive platters for a living, I can tell you that a single fingerprint on a platter is cause to throw the platter away. The thickness of the oil of the fingerprint is enough to cause the head to crash, and that's not nearly as big as a dust particle. No can do.
darksasami, Nov 12 2003

       How about encasing the disk in a tamper-resistant housing ... this makes it more cumbersome, yes, but for servers which use automated back-up systems in which the media is rarely handled anyway, this could be quite useful ...
Letsbuildafort, Nov 12 2003

       //The only real technical challenge is getting a device to access both optical and magnetic media spinning at the same speed.//
Alternatively, if the volume of data on the magnetic portion was fairly small (which I think likely given the suggested applications), you could read the entire magnetic content in one pass and cache it in the player. Then if needed the disk could spin at different rates for the different modes, without much of a penalty.
krelnik, Nov 12 2003

       Darksasami, I don't think this is intended to provide storage density on the level of a hard disk platter, but rather something similar to what can be found in an old 5.25" floppy. By placing a layer of magnetic media within the disk, it may be possible to rewrite some data to the disk, such as last position accessed, in order to let you start where you left off on a DVD. Even though my DVD player is able to identify the last 16 disks that have been played and lets me start where I left off, I give this one a +.
Freefall, Nov 12 2003

       Potential ulterior motive:   

       Patent the way this works, and trademark a cool name for it so consumers know where it is available. License it to DVD player manufacturers as a way to make DVDs easier to use and more customizable.   

       Now deny licenses under your patent & trademark to anyone who makes a rewritable form of this disk. You've just created a significant disadvantage to buying a pirated copy of a DVD....they can't access the customizability features.
krelnik, Nov 12 2003

       [admin: corrected spelling in idea title Opticly -> Optically.]   

       Despite the problems associated with exposed magnetic media, I like this idea for the concept, so + from me.
st3f, Nov 12 2003

       Okay, yeah, that might work--a strip of magnetic tape that holds a few k. If you're going that direction, you might actually be able to work out some kind of floppy-like protective covering. You end up with a disk with moving parts, which is always iffy, but it would, in fact, work. Fishbone rescinded.
darksasami, Nov 12 2003

       "No workie."
"Right, so the magnetic storage area would need to be on an outside surface..."
I don't think so. The read/write head on a hard drive sits close to the platter because it's very low power - it has to be precise. That's not the case here.

       Why not just use DVD+/-RW or CD-RW?
phoenix, Nov 12 2003

       Magneto-optic data storage = MiniDisk (and its ilk). I like [krelnik]'s caching implementation.
Jinbish, Nov 12 2003

       If we're just talking concept, I think a read-only disk with a read-write section has already been made on dataplay disks. Unfortunately, I can't check this at the moment as I am currently sitting behind a seemingly random firewall with a dislike of the domain dataplay.com (link).   

       For me a read-only DVD with a small read-write section would be useful. I could set my preferences up and take them between DVD players. It would beat RW disks by the virtue that nobody could erase data, and would beat a WORM drive by letting me change my preference (lots of times).
st3f, Nov 12 2003

       With the magnetic section on the top side (label side), this could even be retrofitted on existing DVDs by making self stick magnetic media lables. Care would have to be taken in applying these to avoid unbalancing the DVD. This would have the advantage of allowing a manufacturer to implement this and include a large pack of labels with the DVD player so people can use it before it has wide industry acceptance.   

       The one place this wouldn't work would be on double sided disks, but this idea in general wouldn't work with those unless someone developed the magical transparent magnetic media.   

       If we wanted a system that could support double sided disks, the magnetic part could be just on the clear section near the hub. This might require redesigning the mechanism used to hold the disk on some players that clamp the disk using that area. Another option would be to put the magnetic media along the outside edge: the magnatic media would then be a very wide short cylinder. That doesn't work with my label retrofitting idea, and both of these limit the storage capacity.
scad mientist, Nov 12 2003

       If you only need to memorize where the DVD movie was last at you would only need a few hundred bits of information to memorize that would you not?
JoeLounsbury, Nov 12 2003

       An alternative would be to embed a small memory chip in the clear inner hub of the disc, and have contacts on the clamp of the player to communicate with it.   

       I understand that some digital video tapes have a small amount of flash memory inside, though I've no idea what it's used for.
benjamin, Dec 03 2003


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