One terabit per sq.in. HDD using heat. Bad idea?

[db101]

New Fujitsu optical head promises terabit per square inch recording by way of Heat-Assisted Magnetic Recording (HAMR). Hotter hard drives = better chance of drive failure, right? Is it just me, or will using HAMR to heat up hard drives more increase the chances of data loss and/or drive failure?


http://www.tgdaily.com/2006/11/30/fujitsu_head_element_terabit_recording/

 

[joex444]

Certainly not going to argue with the theory, I'm too early in a physics program to dispute any of the ideas.

However, from my Thermal Physics class, a hard drive appears to be a large system of paramagnets. The individual bits can either be 0, 1, or in terms of the little magnets, up or down. This is a 2 state system, known as a paramagnet.

Now, from the book we use, the magnetization of the system is given by (THG sucks for equations):

M = N (mu) * tanh((mu)B/(kT))
where N is the number of paramagnets, mu is the magnet dipole moment (of a single paragamagnet), B is the external magnetic field applied (writing arm, for example), k is Boltzmann's constant, and T is the temperature.

Now, if you're not familiar with the hyperbolic tangent function, it has a range of -1 to 1. As the argument goes to infinity, the tanh function reaches a value of 1. As the arguemet goes to 0, though, the tanh function goes to 0.

Now, as T increases, the argument will be lower, so M is lower. Then when the data is written and it cools back down, T is lower so the argument is higher and M is higher.

Perhaps someone else can answer that.

 

[Prada0007]

I think if the cons were that simple that the actual process of storing the data made it less stable they'd abandon the idea. Maybe they've figured out how the heat makes the data react when data is lost and has found a way to use that to keep the data in check. All theory until the drives are actually out. I'm still waiting for this holo data storage to take off. Hundreds of gigs of data on a piece of holo film the size of a credit card.

 

[joex444]

Since my post with an equation and physics background to it was deleted, I've decided to post again. Hopefully this post won't upset the mods.

There are little elves in the hard drives that remember which bits were hot.

 

[db101]

I suspect they found a way to keep the heat small enough not to impact the life of the drive seriously, I'm just wondering if anyone else thought that heating up drives sounded bad.


I will accept the fact that there are little elves in there to keep track of the hot areas, and maybe they send their baby pet seals to the hot bits to keep 'em from getting too hot. 8)