5 ms·

I think the article is wrong in its core premise. While the electrons get added or removed from the floating gate, the total number of electrons in the SSD chip

I think the article is wrong in its core premise. While the electrons get added or removed from the floating gate, the total number of electrons in the SSD chip stays the same. Gates are capacitors, in order to add electrons to one capacitor plate, you have to remove an equal numbers of electrons from the other plate, i. e. from the transistor channel. The net charge of a SSD chip is always zero. Otherwise it would just go bang. <s>2.43×10^-15</s> [my bad 1] 2.67×10^15 electrons is about 300µC - that's a lot of charge to separate macroscopically. Therefore the mass (weight is a different thing, through it is proportional to mass at a given constant gravity potential) of the data on a SSD isn't fundamentally different from a HDD - they both are caused by a change of internal energy without any change in the number of fermions. I'd expect data on SSD to have larger mass change because a charged capacitor always store more energy than a discharged one, while energy of magnetic domains is less directional and depends mostly on the state of neighbor domains - but I'm not sure about this part. [1] Thanks stackghost.

zahlman 8mo ago
TFA started out seeming well enough written but definitely turned LLM-padded in the middle. And yeah, I think you're right about the actual science.
stackghost 8mo ago
>2.43×10^-15 electrons I believe TFA reads 2.43×10^-15 kg, not electrons. Unless SSDs are creating new and exciting physics, one can't have less than one electron, as it's an elementary particle.
- jmalicki 8mo ago
  Neutrinos weight far less than electrons (but while NAND flash involves super weird physics it's not that weird)
  - stackghost 8mo ago
    They do weigh far less, but a quantity of "10^-15 electrons" is still impossible.
- alanh 8mo ago
  10^–15 is not a negative number, just a small one. https://www.wolframalpha.com/input?i=10%5E-15+ https://www.wolframalpha.com/input?i=10%5E-15+
  - 1718627440 8mo ago
    And it is less than one?
    - JadeNB 8mo ago
      I think my favorite part of that comment is "documenting" that 10^(-15) is not negative by appealing to Wolfram Alpha.
    - agentdrek 8mo ago
      your user name is found at the 4,922,096,564th digit of Pi
  - ChrisClark 8mo ago
    Good thing he didn't say that
  - stackghost 8mo ago
    Yes, you're correct. Now ask yourself if "one quadrillionth of an electron" is a quantity that's possible to have.
- karmakaze 8mo ago
  Well you could have a virtual particle whose mass could be time-averaged.
nickcw 8mo ago
> So, assuming the source material is correct and electrons indeed have mass, SSDs do get heavier with more data. That is definitely wrong! No way the source material has more electrons. The only way it could do that is by being charged. Richard Feynman, The Feynman Lectures: "If you were standing at arm's length from someone and each of you had one percent more electrons than protons, the repelling force would be incredible. How great? Enough to lift the Empire State Building? No! To lift Mount Everest? No! The repulsion would be enough to lift a "weight" equal to that of the entire earth!" From: https://tycho.parkland.edu/cc/parkland/phy142/summer/lectures/lect02/tsld014.htm https://tycho.parkland.edu/cc/parkland/phy142/summer/lecture...
- teaearlgraycold 8mo ago
  Not sure I'd survive that experiment.
  - verelo 8mo ago
    See, now, if this was Reddit...this is the opportunity for a yo momma joke. But here we are on HN, so I'll just point out that this is the opportunity for a yo momma joke.
    - throwup238 8mo ago
      Yo mamma is so fat she broke the Coulomb barrier?
      - verelo 8mo ago
        Well done.
ajross 8mo ago
> energy of magnetic domains is less directional and depends mostly on the state of neighbor domains Yes, but it's the same thing. The flux changes on the drive define the bits. It's probably true that a drive storing all 1's or all 0's would be quantitatively (but surely immesurably) lighter. But in practice a drive storing properly compressed high-entropy data is going to see a flux change every other bit on average. And all of those are regions of high magnetic field with calculable energy density. Same deal as charge in a capacitor, which also stores energy in the field.
_alternator_ 8mo ago
Another bit I’m surprised seems to have gotten completely glossed over: there is a deep relationship between _entropy_ and mass which puts bounds on the amount of information you can place in a given volume. TLDR: a given region of space can’t have more entropy than a black hole of the same volume. Rearranging terms, you find that N bits of information (for large N) has an equivalent black hole size, which in turn has a mass…
Kiboneu 8mo ago
Exactly. On top of that, most managed flash (which is equivalent to SSD controllers) will pass all write through a modified cyclic XOR pad in order to keep the /bit/ entropy high. I don’t think the article holds on multiple abstraction layers.
- LorenPechtel 8mo ago
  Which is the same reason storing data to a HDD doesn't add weight. You can pack the data tighter if you are writing basically balanced 1s and 0s. Thus you can pack more bytes into a given area by encoding them into patterns with even distributions even though that means you need to write more bits.
- tliltocatl 8mo ago
  But SSD erasing must write a constant (either one or zero). So an erased ready-to-write SSD block will have consistently different energy than one written with a random scrambled pattern. Same for SMR HDDs - but not for CMR.
  - Kiboneu 8mo ago
    The SSD lies :) TRIM is a scam. What happens when you XOR a 0 with a byte in a one time pad? You get the corresponding byte from the pad, right? And the block full of 1s or 0s is exactly a case the scrambler needs to be used. It's not for compression or anything like that, it is used because the cells are packed so tightly that sharp changes in energy gradients over the space will even themselves out by donating electrons to their neighbors (flipping bits). It's kind of like rowhammer. Instead of just a ont-time-pad, a more complicated and often proprietary scrambler is used. But it's towards the same end. It's a deterministic, pseudo-random bit sequence. If you can bypass the controller (read directly from NAND) you will see the true values that it returns, and it will likely be scrambled even if the flash controller reports otherwise. This also allows you to recover the scrambler, since you know that the other side of the XOR operation is 0.
    - tliltocatl 8mo ago

zahlman 8mo ago

TFA started out seeming well enough written but definitely turned LLM-padded in the middle. And yeah, I think you're right about the actual science.

stackghost 8mo ago

>2.43×10^-15 electrons I believe TFA reads 2.43×10^-15 kg, not electrons. Unless SSDs are creating new and exciting physics, one can't have less than one electron, as it's an elementary particle.

jmalicki 8mo ago
Neutrinos weight far less than electrons (but while NAND flash involves super weird physics it's not that weird)
- stackghost 8mo ago
  They do weigh far less, but a quantity of "10^-15 electrons" is still impossible.
alanh 8mo ago
10^–15 is not a negative number, just a small one. https://www.wolframalpha.com/input?i=10%5E-15+ https://www.wolframalpha.com/input?i=10%5E-15+
- 1718627440 8mo ago
  And it is less than one?
  - JadeNB 8mo ago
    I think my favorite part of that comment is "documenting" that 10^(-15) is not negative by appealing to Wolfram Alpha.
  - agentdrek 8mo ago
    your user name is found at the 4,922,096,564th digit of Pi
- ChrisClark 8mo ago
  Good thing he didn't say that
- stackghost 8mo ago
  Yes, you're correct. Now ask yourself if "one quadrillionth of an electron" is a quantity that's possible to have.
karmakaze 8mo ago
Well you could have a virtual particle whose mass could be time-averaged.

nickcw 8mo ago

> So, assuming the source material is correct and electrons indeed have mass, SSDs do get heavier with more data. That is definitely wrong! No way the source material has more electrons. The only way it could do that is by being charged. Richard Feynman, The Feynman Lectures: "If you were standing at arm's length from someone and each of you had one percent more electrons than protons, the repelling force would be incredible. How great? Enough to lift the Empire State Building? No! To lift Mount Everest? No! The repulsion would be enough to lift a "weight" equal to that of the entire earth!" From: https://tycho.parkland.edu/cc/parkland/phy142/summer/lectures/lect02/tsld014.htm https://tycho.parkland.edu/cc/parkland/phy142/summer/lecture...

teaearlgraycold 8mo ago
Not sure I'd survive that experiment.
- verelo 8mo ago
  See, now, if this was Reddit...this is the opportunity for a yo momma joke. But here we are on HN, so I'll just point out that this is the opportunity for a yo momma joke.
  - throwup238 8mo ago
    Yo mamma is so fat she broke the Coulomb barrier?
    - verelo 8mo ago
      Well done.

ajross 8mo ago

> energy of magnetic domains is less directional and depends mostly on the state of neighbor domains Yes, but it's the same thing. The flux changes on the drive define the bits. It's probably true that a drive storing all 1's or all 0's would be quantitatively (but surely immesurably) lighter. But in practice a drive storing properly compressed high-entropy data is going to see a flux change every other bit on average. And all of those are regions of high magnetic field with calculable energy density. Same deal as charge in a capacitor, which also stores energy in the field.

_alternator_ 8mo ago

Another bit I’m surprised seems to have gotten completely glossed over: there is a deep relationship between _entropy_ and mass which puts bounds on the amount of information you can place in a given volume. TLDR: a given region of space can’t have more entropy than a black hole of the same volume. Rearranging terms, you find that N bits of information (for large N) has an equivalent black hole size, which in turn has a mass…

Kiboneu 8mo ago

Exactly. On top of that, most managed flash (which is equivalent to SSD controllers) will pass all write through a modified cyclic XOR pad in order to keep the /bit/ entropy high. I don’t think the article holds on multiple abstraction layers.

LorenPechtel 8mo ago
Which is the same reason storing data to a HDD doesn't add weight. You can pack the data tighter if you are writing basically balanced 1s and 0s. Thus you can pack more bytes into a given area by encoding them into patterns with even distributions even though that means you need to write more bits.
tliltocatl 8mo ago
But SSD erasing must write a constant (either one or zero). So an erased ready-to-write SSD block will have consistently different energy than one written with a random scrambled pattern. Same for SMR HDDs - but not for CMR.
- Kiboneu 8mo ago
  The SSD lies :) TRIM is a scam. What happens when you XOR a 0 with a byte in a one time pad? You get the corresponding byte from the pad, right? And the block full of 1s or 0s is exactly a case the scrambler needs to be used. It's not for compression or anything like that, it is used because the cells are packed so tightly that sharp changes in energy gradients over the space will even themselves out by donating electrons to their neighbors (flipping bits). It's kind of like rowhammer. Instead of just a ont-time-pad, a more complicated and often proprietary scrambler is used. But it's towards the same end. It's a deterministic, pseudo-random bit sequence. If you can bypass the controller (read directly from NAND) you will see the true values that it returns, and it will likely be scrambled even if the flash controller reports otherwise. This also allows you to recover the scrambler, since you know that the other side of the XOR operation is 0.
  - tliltocatl 8mo ago