TDK fires up LASERS to double hard drive capacity

HAMR blow to disk heads

homeless man with sign

Japanese disk drive head supplier TDK says it has added a laser heater to its platter licking devices to enable heat-assisted magnetic recording. In non-boffinry speak, this will double disk drives' areal density - and therefore double capacity. All suppliers have to do is come up with the right chemical mix for the platters.

Current perpendicular magnetic recording technology will hit a brick wall in a generation or two: as the size of each stored bit shrinks, the disk capacity increases, but the platters lose their ability to hold the magnetic direction for each bit in a stable manner. There's only so far you can shrink the bits before they stop being useful; it's called the superparamagnetic limit.

A proposed answer is to use a magnetic recording medium with very high coercivity, meaning it's more stable at normal temperatures but needs to be heated before data can be written. This is called heat-assisted magnetic recording (HAMR).

It requires a new recording medium, and read/write heads that can heat very small and precise areas of a disk platter's surface so that bits can be written reliably and in a short space time.

Japan's Asahi Shimbunreports that TDK has built HAMR heads. The report says TDK could manufacture a 2TB 2.5-inch disk drives with 1TB platters using this technology.

Toshiba's MQ01ABD drive has a 1TB maximum capacity today, with two 500GB platters and an areal density of 744.1Gbit per squared inch. So we would be looking at areal densities of around 1.5Tbit per squared inch, if TDK's science turns into reality.

If applied to four-platter 4TB 3.5-inch drive, we would be looking at an 8TB model. That's an enticing prospect.

TDK is playing its cards close to its chest, as are the hard disk drive companies. We have no idea of the pricing of TDK's HAMR head and no idea of how or when HAMR disk drives might come about. The drive industry generally has a Storage Technology Alliance to work on future technologies as any development beyond the current technology looks hugely expensive for any one company to bear.

It's expected that HAMR alone won't be enough to increase areal density as much as customers will want and an additional bit-patterned media (BPM) concept will be needed as well. Hitachi GST has talked about this here. ®

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