• Hi Guest: Welcome to TRIBE, the online home of TRIBE MAGAZINE. If you'd like to post here, or reply to existing posts on TRIBE, you first have to register. Join us!

Mass or Entropy of information

Jeffsus

TRIBE Member
Let's do a thought experiment.

Take a random hard drive, or SSD or thumb drive or whatever.

Measure the mass of that device. Oh, measure it very carefully. We can discuss about how to measure it later. I think it involves acceleration. Anyway....

Now, put some information into this device.

At a minimum, there are three possibilities.

1. The device has the same mass due to conservation of mass/energy
2. The device has more mass because work has been done upon it
3. The device has less mass because it is more orderly and 3rd law of thermodynamics etc. etc.

I am looking for a bright individual to solve, or explain, this problem.

-jM
A&D
 
Stop Bill C-10

Jeffsus

TRIBE Member
Hey AlexD, your service provider didn't work out so well for my last post.

Regardless, I have been thinking about this for, well, now two days.

I think the answer is that, by putting information onto it, the device must measure LESS.

This conclusion is non-intuitive. Nonetheless, it is the only conclusion that agrees with thermodynamics, in particular, the 3rd law.

I will briefly explain this conclusion before going to well deserved bed.

Entropy/Enthalpy is always increasing. But in a local area, that's not the case. A hard drive, an SSD, DNA, a living creature -- all are examples of decreasing entropy, and increasing orderly information. Yes, that comes at the expense of the universe.

Therefore, much like a Carnot engine, energy and therefore mass MUST be decreasing.

ndrwrld, please help me to design an experiment that can measure mass to very accurate levels.

Best regards,

Jeff
 

Bass-Invader

TRIBE Member
The energy used to decrease the entropy of the HDD comes from an external input (the computer's power supply). Therefore the mass can stay the same without violation of the 3rd law.
 

Jeffsus

TRIBE Member
The energy used to decrease the entropy of the HDD comes from an external input (the computer's power supply). Therefore the mass can stay the same without violation of the 3rd law.

Yes of course, nobody is questioning thermodynamics. Entropy/Energy/Enthalpy is coming from some external source.

My basic question is, if I can phrase it: (let's pick one):

Does a hard drive decrease in mass as you put more information on it?

I can rephrase this question but I think you get it.

Jeff
 
tribe cannabis accessories silver grinders

Bass-Invader

TRIBE Member
No. Not unless you found a way to store information on it without adding energy from an external source. If you did, then presumably some of the HDD would be consumed into energy and heat, reducing its mass and preserving the 3rd law (but thats all speculation since we cannot do this yet).
 

Jeffsus

TRIBE Member
No. Not unless you found a way to store information on it without adding energy from an external source. If you did, then presumably some of the HDD would be consumed into energy and heat, reducing its mass and preserving the 3rd law (but thats all speculation since we cannot do this yet).

Well, Bass-Invader, I think you are wrong here.

I have seriously been staring at this screen for three hours.

I don't know how to articulate my opinion.

Overall, of course, entropy increases... but locally, by making the device more orderly, it MUST decrease in mass...??

It is now 19:38. Do you want to phone or PM me?

Jeff
 

Jeffsus

TRIBE Member
I haven't quit this question.

It's relentlessly fascinating me.

The answer is that the localized system MUST have less mass!!

Jeff
 

Bass-Invader

TRIBE Member
The HDD before and after you write stuff to it has the same number of bits built into it. The amount of information on a new HDD (all zeroes) and one that has had stuff written to it is the same.

The only possible difference in mass *might* be due to interactions between the magnetic fields of the bits, but that is not really relevant your question (not related to information/entropy, but to the construction of the device.)
 

Jeffsus

TRIBE Member
The HDD before and after you write stuff to it has the same number of bits built into it. The amount of information on a new HDD (all zeroes) and one that has had stuff written to it is the same.

The only possible difference in mass *might* be due to interactions between the magnetic fields of the bits, but that is not really relevant your question (not related to information/entropy, but to the construction of the device.)

A disk drive has platens and nowadays uses magneto resistance (or something -- sounds like a comic book character -- google it) A flash drive does have transistors, and my favourite, capacitors!! (suck on THAT Sporty Dan).

But the level of mass change I am talking about is MUCH less.

You know, I think we should use a HDD as our example because, as you mentioned, physically, there is no change to the device. For example, formally speaking, the number of particles (ideally) is not changing. Whereas a flash drive, which does physically move electrons and thus (ever so slightly) mass... But I am not talking about that kind of mass. I have a book here, somewhere, it's related to the Equivalence principle, which appropriately, describes two kinds of mass, which are equivalent.

Bass-Invader, I am not talking about mass on the scale of any particles, not even the electron, which is not massive at all. Rather, in much the same way that there is equivalence between matter and energy (our good friend E=MC^2) there is also an equivalence between matter and entropy.

So, I am slightly less drunk today, so I feel I have a good attempt at this problem.

Bass-Invader, you made an error about the Hard Disk Drive. The device does not start as "all zeroes". In fact, were it to start as all zeroes, that would be very highly ordered. The magnetoresistance (I really have to check if this is the correct term) at any point is random. Once formatted, it becomes LESS random, ie. more orderly, ie. the entropy has decreased (locally). Therefore, the overall energy/entropy of the device has decreased. Therefore, the mass must also decrease!

OK I have convinced myself that the mass decreases as more information is recorded. Now, I will calculate by how MUCH the mass decreases.

It's a remarkably small amount of mass, and it is the second kind of mass, ie. relativistic mass, in the equivalency principle.

You know, this part is going to be a lot more difficult....
 
tribe cannabis accessories silver grinders

Jeffsus

TRIBE Member
The HDD before and after you write stuff to it has the same number of bits built into it. The amount of information on a new HDD (all zeroes) and one that has had stuff written to it is the same.

Agreed. The physical construction of the device is not what I'm talking about. The scale of mass of the physical construction is orders of magnitudes greater than the mass of entropy/information.


The only possible difference in mass *might* be due to interactions between the magnetic fields of the bits, but that is not really relevant your question (not related to information/entropy, but to the construction of the device.)

Au contraire, this is exactly what I'm talking about. The decreased randomness of the magnetic fields is exactly how the information is stored and is exactly why there is less mass in a HDD that has more information.

Jeff
 

Jeffsus

TRIBE Member
Ok I'm getting a bit drunk again and increasing my research.

I like how scientists really are not good Marketeurs.

I knew I was right, about Giant Magnetoresistance, and I was right about X-Men, they stole the name.

What I didn't realize is that there was "Ordinary Magnetoresistance". Ha, who wants to be ordinary?

Then comes COLLOSAL magnetoresistance. Now that has a heavy name. But who is satisfied with just Collosal?

EXTRAORDINARY MAGNETORESISTANCE.

magneto.gif


FUCK yeah where's my cute Chinese co-op!

Hey wait isn't this actor gay too?

-jM
A&D
 

Bass-Invader

TRIBE Member
Au contraire, this is exactly what I'm talking about. The decreased randomness of the magnetic fields is exactly how the information is stored and is exactly why there is less mass in a HDD that has more information.

Jeff

Decreased randomness from what? At what point are a HDD's bits ever random? In fact, if you actually used a real random generator to set the HDD's bits, they would stop being random the minute you read them - yet that would not reduce the 'mass', nor the energy stored by the magnetic field differentials.

In any event, since you're talking about the 'mass' coming from the potential energy of the magnetic field differentials, it would be a very-un-random state that would have the most mass. Simply, a sequence of alternating 1 and 0 bits spanning the entire disk.
 
tribe cannabis accessories silver grinders

Jeffsus

TRIBE Member
Decreased randomness from what?
At what point are a HDD's bits ever random? In fact, if you actually used a real random generator to set the HDD's bits, they would stop being random the minute you read them - yet that would not reduce the 'mass', nor the energy stored by the magnetic field differentials.

Ok, did you... Did you see the pic of EXTRAORDINARY MAGNETORESISTANCE?

The gay guy, X-MAN, You did see that pic right?

There are NO bits on an HDD.
In any event, since you're talking about the 'mass' coming from the potential energy of the magnetic field differentials, it would be a very-un-random state that would have the most mass. Simply, a sequence of alternating 1 and 0 bits spanning the entire disk.

No. An HDD does not have bits.

Whatever. I've already agreed with myself that a hard drive has less mass as you record more information on it. If you disagree with me, then you are wrong.

The question is now HOW MUCH MASS?

Jeff
 

Jeffsus

TRIBE Member
"In general, a good minimum is E=6kT. That's 10−20J/bit at room temperature, or 10−9J=10−26kg for a 1 TB drive."

Thank you Bernie Federko!

I can't believe someone else has bothered to think about this.

-jM
A&D
 
tribe cannabis accessories silver grinders
Top