3 ms·

Heat-assisted magnetic recording

14 points by luu 11y ago

tedsanders 11y ago
Various thoughts on this technology: +Hard drive progress has been slowing since the last major advance in the 2000s (tunnel magnetoresistance read heads, which are now maturing). Heat-assisted magnetic recording (HAMR) is the most likely next evolution of hard drives. +The main problem with increasing bit density on hard drives is as you make the bits smaller, they become less stable. You can increase their stability by increasing their magnetic coercivity, but then the tradeoff is that the bits become harder to write. Heat-assisted magnetic recording is a technology that makes bits easier to write, which will make it possible to use smaller (higher coercivity) bits. +The idea is not new, and it even enjoyed commercial realization in the 1980s in magneto-optic discs. +Seagate is one of the leaders in HAMR technology, but their release dates keep getting pushed back. Right now the latest word is that they'll be commercially available in 2017. +I've heard the main problem with HAMR now is the thermal stability of the plasmonic antenna. Because the magnetic bits are much smaller than the wavelength of laser light, conventional optics cannot be used. Instead, the head has a vertical waveguide with a plasmonic antenna at the end, which concentrates the light at the bit being written. Unfortunately, a side-effect of heating the magnetic bits is that the antenna also gets hot, and they can fail after just ~100 writes. Engineers are working to solve this and I'm confident they will, but right now this is the main problem with HAMR and why it's taken so long to get to market, at least from what I've heard. Source: I am a magnet scientist
- castratikron 11y ago
  I did my thesis on computer simulations of heated magnetic grains for HAMR research. They say that this tech could provide densities up to 1TBit/in^2.
  - SMR1 11y ago
    You can buy regular (not HAMR) HDDs with the same areal density of 1TBit/in^2 today: Seagate 8TB Archive HDD, Toshiba 2.5" HDD.
    - castratikron 11y ago
      Can I guess by your username that they use shingled magnetic recording? I did that thesis a few years ago and I never went into the field. I remember SMR and HAMR being the two big ideas at the time.
cnvogel 11y ago
The submitter might have been triggered to look the topic up on Wikipedia by the most recent (Aug 10, 2015) installment on Ben Krasnow's Applied Science videos: Learn how magneto-optical storage discs work, and see how a focused laser can directly alter a material's optical characteristics. https://www.youtube.com/watch?v=UTquUbvzJII https://www.youtube.com/watch?v=UTquUbvzJII This video uses a magneto-optical disk as an example material, but there also the material is heated up above the curie point to allow the bit-domains to swap orientation. Readout is optical, though. (hence the name)
scottlocklin 11y ago
People forget the NeXT Cube originally came with a version of one these (magneto optic read outs based on Kerr Rotation); Jobs was a visionary for certain. I actually worked on a version of this (Cobalt-Platinum multilayers) for a summer internship with Mark Kryder at the Data Storage Systems Center; a formative experience for me. The Seagate technology described here is probably largely based on his work.

14 points by luu 11y ago

Various thoughts on this technology: +Hard drive progress has been slowing since the last major advance in the 2000s (tunnel magnetoresistance read heads, which are now maturing). Heat-assisted magnetic recording (HAMR) is the most likely next evolution of hard drives. +The main problem with increasing bit density on hard drives is as you make the bits smaller, they become less stable. You can increase their stability by increasing their magnetic coercivity, but then the tradeoff is that the bits become harder to write. Heat-assisted magnetic recording is a technology that makes bits easier to write, which will make it possible to use smaller (higher coercivity) bits. +The idea is not new, and it even enjoyed commercial realization in the 1980s in magneto-optic discs. +Seagate is one of the leaders in HAMR technology, but their release dates keep getting pushed back. Right now the latest word is that they'll be commercially available in 2017. +I've heard the main problem with HAMR now is the thermal stability of the plasmonic antenna. Because the magnetic bits are much smaller than the wavelength of laser light, conventional optics cannot be used. Instead, the head has a vertical waveguide with a plasmonic antenna at the end, which concentrates the light at the bit being written. Unfortunately, a side-effect of heating the magnetic bits is that the antenna also gets hot, and they can fail after just ~100 writes. Engineers are working to solve this and I'm confident they will, but right now this is the main problem with HAMR and why it's taken so long to get to market, at least from what I've heard. Source: I am a magnet scientist

castratikron 11y ago
I did my thesis on computer simulations of heated magnetic grains for HAMR research. They say that this tech could provide densities up to 1TBit/in^2.
- SMR1 11y ago
  You can buy regular (not HAMR) HDDs with the same areal density of 1TBit/in^2 today: Seagate 8TB Archive HDD, Toshiba 2.5" HDD.
  - castratikron 11y ago
    Can I guess by your username that they use shingled magnetic recording? I did that thesis a few years ago and I never went into the field. I remember SMR and HAMR being the two big ideas at the time.

cnvogel 11y ago

The submitter might have been triggered to look the topic up on Wikipedia by the most recent (Aug 10, 2015) installment on Ben Krasnow's Applied Science videos: Learn how magneto-optical storage discs work, and see how a focused laser can directly alter a material's optical characteristics. https://www.youtube.com/watch?v=UTquUbvzJII https://www.youtube.com/watch?v=UTquUbvzJII This video uses a magneto-optical disk as an example material, but there also the material is heated up above the curie point to allow the bit-domains to swap orientation. Readout is optical, though. (hence the name)

scottlocklin 11y ago

People forget the NeXT Cube originally came with a version of one these (magneto optic read outs based on Kerr Rotation); Jobs was a visionary for certain. I actually worked on a version of this (Cobalt-Platinum multilayers) for a summer internship with Mark Kryder at the Data Storage Systems Center; a formative experience for me. The Seagate technology described here is probably largely based on his work.