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Cylindrical Optical 'Disks'

They would come in a range of different sizes that can fit within one another, to waste less space.
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This idea is for cylindrical optical 'disks' and a drive to read/write them.

The 'disks' would come in a range of sizes/capacities which would 'stack' together to waste less space. The largest 'disk's diameter would probably be approximately 12 centimeters (the same diameter as a traditional disk), and the smallest 'disk's diameter would probably be approximately 4 centimeters. The width of each 'disk' would probably be about 2 centimeters, but that could be different.

The 'disks' could have information on either the inside of the cylinder, the outside, or both. I think having the information only on the inside would be the best in most cases because it would allow labeling to be on the outside of the 'disk', and it could be handed easily without worrying very much about scratching the information.

The drive would be able to read all the different sizes of 'disks' without any physical adjustments of the drive or any of it's parts. I'm imagining that the laser would be in the center of the 'disk', with a motorized wheel on the outside of the 'disk', this way the 'disk' size doesn't matter.

One advantage is that the drive motor runs at a constant speed because of the 'disk's geometry, which is good, and theoretically would require less electricity. Another advantage of these over traditional disks is that you could store many of them (different sizes) in one case, which would require less plastic material for cases and would save space, although there would still be a void in the center.

A cone would also be available to help you retrieve specific 'disks'.

BJS, Aug 13 2007

Optical disc http://en.wikipedia.../wiki/Optical_media
You decide the format. [BJS, Aug 13 2007]


       I'm not sure whether i got it: You are proposing 2cm high cylinders of varying diameter, that could be stacked inside each other? How would a fully stacked stack of those things differ from cds stacked 2cm high?
loonquawl, Aug 13 2007

       Drum storage is nothing new.
AbsintheWithoutLeave, Aug 13 2007

       storage capacity relative to cd:   

       cylinder = 2*pi*r*h - at 12cm diameter, 2cm height => 24*pi cm^2   

       Disk = pi*r2^2 - PI*r1^2 where r1 is the inner radius and r2 is the outer - at r1 = 2cm, r2 = 6cm => 32*pi cm^2   

       I fail to see the point. If they were stacked inside each other the storage density would be exactly the same as a 2cm high stack of cds.
miasere, Aug 13 2007

       It seems to me that this would end up with less actual storage area. Ok, checked my figures and I am wrong.   

       Lets see, a twelve centimeter by two cm cylinder has 75.4 sq cm of area.   

       If each cylinder is a millimeter thick and requires a half millimeter clearance, then then next possible smaller size is 11.85 cm. Which would have 74.46 of area.   

       Continue that down and you end up with a two centimeter cylinder with 13.19 sq cm of area.   

       Added up you get 2967.86 cm of total writable area.   

       A cd has 109.96 sq cm of area (assuming twelve cm diameter, two cm diameter no writable center.)   

       Twenty of those is 2199.11 less 35% more writable area.   

       Of course getting to the 6 centimeter cylinder is going to require removing either the inner 26 cylinders or the outer 41.   

       And none of the cylinders has more than about two thirds the recording capacity of an individual CD.
Galbinus_Caeli, Aug 13 2007

       optical storage will be dead in 20 years anyway. Each medium has about a 20 year life cycle before they are stuck in the bargain buckets at service stations
miasere, Aug 13 2007

       [Galbinus_Caeli], the "no writable center" of a CD if greater than 2 centimeters diameter, it's closer to 2 centimeter radius.   

       Do you know how tall a stack of 20 CDs would be including the thickness of their casing? The thinnest possible casing are those thin flexible "pages".   

       I don't understand how you think 2199.11 sq cm is 35% more writable area than 2967.86 sq cm?   

       The width of the disks doesn't really matter, I just said 2 cm because I though a drive could be made for that that would fit in a normal drive bay of a computer.   

       A possible solution to retrieving a specific cylinder is to use a cone. You simply lower the "stack" of cylinders around the cone until you see the desired cylinder, then you lift the specific cylinder vertically to remove it from the other cylinders.
BJS, Aug 13 2007

       Sorry [BJS] I meant to write "LESS" writable area for the CD rather than your cylinders. (I will edit to correct.) And you are right about the size of the non-writable area, it is four centimeters diameter.   

       I was assuming no casing at all, just a stack of CDs on a spindle (Almost none of my non music CDs are in any kind of case, I keep them spindled).
Galbinus_Caeli, Aug 13 2007

       Ok. I guess you could just keep them on a spindle, but a spindle has the same problem with accessing specific disks as my idea does.
BJS, Aug 14 2007

       How about optical tape? Tape drive systems use a huge amount of surface area for storage.
supercat, Aug 14 2007

BJS, Aug 14 2007


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