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Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

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Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#51

Post by Layke1123 »

phildenhoff wrote: post #24
tyingq wrote: post #16

Earlier quoted context omitted.

There's a detailed explanation here: https://chemistry.stackexchange.com/questions/115363/is-a-hy... Edit: Oops. Still relevant since it's H2 in play here, but yes, not hyrdrogen vs helium.

I think that explanation is only about Hydrogen molecules and hydrogen atoms, not Hydrogen vs. Helium. There's a free textbook available here [1] that explains that atomic sizes decrease across the periodic table and increase down. In short, it decreases across a horizontal period because more electrons are in the same orbital shell (really a cloud), increasing the negative nuclear charge of the cloud, which is more…

This seems unintuitive as I would expect one electron by itself to be more closely attracted to a positive nucleus instead of when there are two or more fighting to remain in "orbit".

Your definition would make sense to me if you can think of electrons adding to an over all single electrical charge instead of individual electrons, but in that case, I have to ask, what is the original reason a single electron is repulsed by the atom. I.E. why does it stay so far away until more electrons are added. What is the force keeping electrons from falling into the nucleus in the first place and have an "orbital" or "cloud" at its set distance (like one Angstrom or Bohr)?

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#52

Post by sbierwagen »

sandworm101 wrote: post #40
gibspaulding wrote: post #39

Earlier quoted context omitted.

> "Let’s say you have an MRI scanner with the OR76 magnet with the full capacity of 1800 litres of helium. Your system consumes approximately 4% of its helium capacity per month, that sums up to 48% per year (4%12 = 48%). That means that 864 litres are consumed per year (1800 litres 48% = 864 litres)." I know this is napkin math so it doesn't really matter, but a 4% loss times 12 months would be 1-(.96^12) = 39%. Unl…

I'm not sure that the percentage matters in cooling. This stuff is cooling working parts (magnets). Boiling is therefore related to the amount of heat needing to be absorbed rather than the amount of helium in the tank. A half-empty machine would probably need to boil off just as much helium per time/use/work cycle as a full one. The other error I now realize is that these HDDs probably have much less helium than any…

Superconducting magnets don't produce heat. (They are superconducting) All the heat comes from the resistive feeder cables and the walls of the cryostat.

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#53

Post by ahartmetz »

Covzire wrote: post #50
ksec wrote: post #45

For those who haven't been following HDD closely. Energy Assisted Magnetic Recording, EAMR is a term that sums up both MAMR, Microwave Assisted Magnetic Recording and HAMR, Heat Assisted Magnetic Recording. And this isn't the first 18TB HDD, there are 20TB HDD already. Nor the first MAMR drive. Western Digital Ultrastar DC HC550 [1] claims that title. MAMR will bring us some incremental gains, both WD and Seagate bel…

Is transistor density somehow holding back magnetic storage density too or something else?

Magnetic storage density is held back by how small you can make a bit (magnetic domain) and still be able to write it AND not have it succumb to random flips due to thermal energy. EAMR works by temporarily making tiny magnetic domains of a hard to flip material easier to flip while under the influence of additional energy.

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#54

Post by wmf »

Covzire wrote: post #50
ksec wrote: post #45

For those who haven't been following HDD closely. Energy Assisted Magnetic Recording, EAMR is a term that sums up both MAMR, Microwave Assisted Magnetic Recording and HAMR, Heat Assisted Magnetic Recording. And this isn't the first 18TB HDD, there are 20TB HDD already. Nor the first MAMR drive. Western Digital Ultrastar DC HC550 [1] claims that title. MAMR will bring us some incremental gains, both WD and Seagate bel…

Is transistor density somehow holding back magnetic storage density too or something else?

No, AFAIK the limit is caused by various tradeoffs between the media material and read/write head design (the Magnetic Recording Trilemma).

http://www.fgarciasanchez.es/thesisfelipe/node5.html

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#55

Post by theandrewbailey »

calchris42 wrote: post #44
wccrawford wrote: post #42

Earlier quoted context omitted.

Wouldn't the real problem be other things leaking back in? If the helium just leaves, that's a vacuum. If only helium can pass, then it's going to stay helium in there.

I believe helium is used due to it being more effective than air at removing heat. Vacuum is significantly less effective (as in, no convection in a vacuum)

I heard that it was because helium filled drives have less drag on platters (thus, are more efficient) than air filled drives.

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#56

Post by moonbug »

thesz wrote: post #43
wccrawford wrote: post #42

Earlier quoted context omitted.

Wouldn't the real problem be other things leaking back in? If the helium just leaves, that's a vacuum. If only helium can pass, then it's going to stay helium in there.

Helium can leak into and between crystals in the metal inside the container and container itself. That process changes dimensions and mechanical properties of construction. In this particular case I see it as a planned deprecation, sort of.

drives like this will typically be rated for a 5yr operational life.

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#57

Post by moonbug »

sandworm101 wrote: post #34
FooBarWidget wrote: post #31

Earlier quoted context omitted.

A party balloon full of helium is a minuscule amount?

Note this is liquid helium in one operational MRI machine: "Let’s say you have an MRI scanner with the OR76 magnet with the full capacity of 1800 litres of helium. Your system consumes approximately 4% of its helium capacity per month, that sums up to 48% per year (4% 12 = 48%). That means that 864 litres are consumed per year (1800 litres 48% = 864 litres)." https://lbnmedical.com/liquid-helium-in-mri-machine/ That…

balloon gas is typically about 90% helium and is generally a recycling of helium expended in industrial applications.

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#59

Post by GeorgeTirebiter »

moonbug wrote: post #56
thesz wrote: post #43

Earlier quoted context omitted.

Helium can leak into and between crystals in the metal inside the container and container itself. That process changes dimensions and mechanical properties of construction. In this particular case I see it as a planned deprecation, sort of.

drives like this will typically be rated for a 5yr operational life.

If there is leakage, I wonder how long it would be before the data could not be recoverable? Could one transplant the platters and 're-charge' the Helium? Or just somehow recharge the old disk? Because unless / until we get some cheap lots-of-bit storage, all the 'stuff' we're generating will not be, in effect, archivable. Is this right?

Re: Toshiba Unveils First FC-MAMR HDD: 18 TB, Helium Filled

#60

Post by ridgeguy »

yummypaint wrote: post #3

This seems like a terrible use of helium from a sustainability perspective. There are some things that helium is truly essential for, like low temperature cryogenics and neutron detection. Our supply is finite and largely tied to natural gas reserves. When helium leaks out it floats into space and is gone forever. Why does the atmosphere in the drive absolutely have to be helium? Why not any other mix of inert gases…

I think helium is used for its low kinematic viscosity. That lets the R/W head fly closer than, for example, air. The other inert gases (Ar, Ne, etc.) have KV values higher than air and would give no advantage. He is better for thermal reasons, too.
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