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Seagate to storage bods: You CAN touch this (at last). Stop, HAMR time

We've talked about it for a while... next month, you'll actually *see* it

HAMR image

Seagate plans to demonstrate a coming HAMR disk drive in Tokyo next month.

HAMR stands for heat-assisted magnetic recording and is a way of increasing a disk drive's capacity beyond the limits of current perpendicular magnetic recording (PMR) technology.

At high areal densities PMFR technology breaks down because each bit becomes susceptible to its magnetic charge changing, due to interference from neighbouring bits and from temperature fluctuations. It is thought the likelihood of random bit-value changes like this will happen increasingly once recording densities pass 800 Gbit/in2.

HAMR technology uses a magnetic recording medium that is resistant to bit-value fluctuations, and hence data writes, at normal temperatures. When heated however, a bit's magnetic charge can be readily changed and HAMR read/write heads incorporate a laser to do that, with the beam aimed at the bit's location so it can be momentarily heated, the bit value written, and then the bit area cools and becomes stable again.

Seagate reckons this could possibly lead to a whopping 20TB capacity disk drive by 2020, one with a lower cost/GB than other recording technologies.

It says the HAMR technology will be combined with "self-ordered magnetic arrays of iron-platinum particles", suggestive of the notion of bit-patterned media. The two will, it suggests, eventually reach a 50Tbit/in2 areal density.

Currently Seagate is shipping PMR disk drives and developing shingled magnetic recording (SMR) drives, ones with a greater number of PMR tracks, of which it says a million have already been shipped. No actual SMR disk product has been announced though.

Seagate says it will produce a 2.5-in form factor HAMR disk drive, spinning at 10,000rpm, and for use in enterprise blade servers environments.

1Tbit/in2...

We understand Seagate aims to ship its first HAMR drive in 2014. In March 2012 Seagate said it had built a 1Tbit/in2 HAMR drive.

Our thinking is that Seagate won't produce HAMR versions of its 15,000rpm Savvio drives because data that needs such fast access is moving to NAND storage. A 10K rpm HAMR drive could provide a mix of access speed, capacity and cost/GB that flash cannot meet.

HAMR image

HAMR disk drive head schematic

Will there be hybrid HAMRs? Ones with an on-board flash cache? We would think so, as they would greatly increase data access speed without substantially increasing the cost/GB

Seagate's 2.5-inch 10K Savvio 10K.6 product stores up to 900GB on three platters with a 538Gbit/in2 areal density, using PMR, and a 6Gbit/s SAS interface. The follow-on PMR technology Enterprise Performance 10K.7 drive stores up to 1.2TB using the same areal density.

A HAMR follow-on model could be called an Enterprise Performance 10K.8 and its capacity could head towards 2TB. We'd guess it would hit 1.5TB with three platters.

The company will demonstrate its HAMR technology at CEATEC 2013 form today, 1 October, until Saturday, 5 October, 2013 at Makuhari Messe in Tokyo. ®

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