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Seagate's HAMR to drop in 2020: Multi-actuator disk drives on the way

Fast and slow high-cap disk lines coming

In 2020 Seagate will introduce its first multi-actuator disk drives using Heat-Assisted Magnetic Recording (HAMR) tech with 20TB capacities.

This was revealed at the Open Compute Project summit, which took place yesterday and today at the San Jose Convention Center. Wells Fargo analyst Aaron Rakers was there and distributed this Seagate presentation slide:


HAMR is a way of shrinking a disk drive's magnetised bits beyond the limits of current PMR (Perpendicular Magnetic Recording) tech, in which progressively smaller bits become unstable with error-prone bit values.

HAMR technology involves a more stable magnetic recording layer, needing transitory heating of a bit area so a bit value can be written to it.

Multi-actuator technology involves dividing a disk drive's platter reading and writing head stack into upper and lower halves and operating them in parallel to increase the drive's overall IO speed. Seagate's slide talks of maintaining an 8-10 IOPS/TB level.

The average number of IOPS per terabyte has been and is falling as disk capacity rises because there is a single read/write head assembly stack with one readwrite head/platter – a chokepoint. It will continue to fall as disk capacities rise further – see the lower line on the chart above.

Seagate is shown introducing a 14TB drive with multiple actuators in 2019, using a PMR technology drive. This will be a high-capacity drive with more performance than single actuator drives.

It will be followed by a multi-actuator HAMR drive with 20+TB capacity in 2020, followed in turn by 30+TB drives in 2021/2022 and 40+TB around 2023.

Single-actuator, and therefore slower, HAMR drives will be introduced with a 20+TB model in 2020, a 30+TB drive in 2021/2022 and a 40+ TB one in 2022/2023.

Rakers writes:

Seagate believes it can maintain a 10x $/GB gap between HDDs and SSDs through the leverage of next-generation technologies such as HAMR to drive to 2Tbpsi areal density (supporting 20TB HDDs) and ultimately 10Tbpsi (100TB HDDs), supporting a forecasted nine-year areal density CAGR of +30 per cent.

We can be fairly certain that both Western Digital and Toshiba have multi-actuator technology in their roadmaps. WD has its MAMR (Microwave-Assisted Magnetic Recording) technology to boost capacity beyond PMR limits and we await a Toshiba pronouncement on what it will do to go beyond PMR in order to keep increasing capacity along with its competitors. ®

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