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crispyambulance

It makes me wonder, is there a hard physical limit on what is possible for data storage density?

Hardrives are roughly 1Tb/in^2 in areal density right now. SSD's are a little better.

This one using hydrogen atoms is ~100x better.

Hydrogen atoms are pretty damn small. Aside from improvements with 2D packing factor, is this pretty much the limit?

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There is such a limit to areal density. The math involved dives into entropy and the planck length, but the short answer is that any information at a quantum level must be quantized in some form and the smallest possible quantization is the planck length squared, called the "planck area".

reference: https://physics.stackexchange.com/a/2283

this is probably a silly question, but why isnt the smallest possible quantization just planck length, or planck length cubed?

I think they're talking about _area_ specifically.

The idea is that our universe has three spatial dimensions, but only two are needed to represent a given volume of space. All the information is on the boundary surface.

In other words, we live in a hologram.

The holographic principle says that all of the information required to represent a 3-D volume is encoded on the 2-D surface of its boundary i.e. in one sense there is no difference between e.g. a black hole and its surface.

https://en.wikipedia.org/wiki/Holographic_principle

It's actually 2x2 Planck lengths per bit, so 4 Planck areas.

https://en.wikipedia.org/wiki/Bekenstein_bound

>Hardrives are roughly 1Tb/in^2 in areal density right now. SSD's are a little better.

I am pretty sure 1Tb is 1 Terabit/in^2. Here it is 138 Terabytes / in^2, or 1104 Terabit/in^2, hence the 1000 times difference. Not 100

Western Digital MAMR allows up to 4 Terabit/in^2, so the difference is now slightly closer to ~250x. Then there is Bit pattern media, which should get us to 10 Terabit/in^2.

But it doesn't look like HDD manufacture are in any hurry, they will try to milk the market for as long as possible. The Total HDD market will fall to 50% of its peak volume sometimes next year or in 2020.

What's causing the drop in demand? Anyone know?

I suspect its flash memory (eg: SSD) taking over all uses except for bulk storage and low end computers where $/gb is the only thing that matters.

Low end computers will eventually go SSD too. The cost of a hard drive has a floor for all the mechanics that go into it. Moores law may be petering out but I think it will still deliver usably large SSDs below that floor.

Falling PC Shipment. Notebook transition to SSD. The move to cloud computing, where Cloud providers chooses higher capacity unit rather then slightly cheaper price per GB model. Obviously the TCO flavours the former on power and space usage.

maybe your peak volume numbers should be normalized by unit capacity.

True. But but even if you had double the capacity at half the unit shipment, it would still have used half of the motor, half of the casing, assembly, heads etc.....

In terms of business isn't exactly good.

hard drive manufacture is economic- it's like oil, with volumes enough that there is a liquidity to the market.

I would expect that the market will drive hard drive manufacturers to effectively zero profit.

This is a good thing for everybody.

https://en.m.wikipedia.org/wiki/Bekenstein_bound

It gives the maximum amount of data in space before collapsing into a black hole.

And it's something like 10^35 hellabits / mm³, so we have a ways to go.

Maximum mathematical is not the same as maximum achievable

Yeah, but both are very interesting, as are specific constraints that can be applied, like what's possible in 1D or 2D or 3D and how quantum mechanical phenomena enters into the limitations.

Helps the discussion to bracket possibilities. If there's an absolute hard limit somehow, let people know so they don't assume it's possible to go further.

I find this useful in discussing solar power: there is an absolute maximum of 1300 watts per square meter; most people don't know this and implicitly assume substantially higher is achievable.

The amusing thing about the Bekenstein bound is that it's per millimetre squared, not per millimetre cubed. The amount of information you can pack into a given region of space scales like length^2, not length^3.

For the sorts of scales human beings are interested in, of course, the Bekenstein bound is a long long way from being relevant, and what matters for us in principle is volume rather than area. (There are practical difficulties in using "substantially" 3-dimensional regions for storage, but they have nothing to do with the danger of the storage device turning into a black hole.)

It’s about surface area and a cubic mm has a certain surface area.

A cube (square prism) enclosing a cubic millimeter has more surface area than a sphere enclosing the same volume.

A cubic mm black hole is always a sphere.

What a coincidence I was reading Feynman's 'Plenty of room at the bottom' lecture just this morning!

https://en.wikipedia.org/wiki/There%27s_Plenty_of_Room_at_th...

Theoretically, you could store information in the spin state of every electron in an atom. For gold, for example, that would yield 79 bits per atom.

Researchers are looking into this, this field as a whole is supposed to be called "spintronics".

No... You could theoretically store information in the spin state of a few valance atoms, but all of the tightly bound atoms are already filling all of the spin states.

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