Marking an important step in the development of next-generation hard drive technology, Western Digital has formally announced the company’s first hard drives based on energy-assisted magnetic recording. Starting things off with capacities of 16 TB and 18 TB, the Ultrastar DC HC550 HDDs are designed to offer consistent performance at the highest (non-SMR) capacities yet. And, with commercial sales expected to start in 2020, WD is now in a position to become the first vendor in the industry to ship a next-generation EAMR hard drive.

18 TB Sans SMR

The Western Digital Ultrastar DC HC550 3.5-inch hard drive relies on the company’s 6th Generation helium-filled HelioSeal platform with two key improvements: the platform features nine platters (both for 16 TB and 18 TB versions), and they using what WD is calling an energy-assisted magnetic recording technology (EAMR). The latter has enabled Western Digital to build 2 TB platters without using shingled magnetic recording (SMR).

Since we are dealing with a brand-new platform, the Ultrastar DC HC550 also includes several other innovations, such as a new mechanical design. Being enterprise hard drives, the new platform features a top and bottom attached motor (with a 7200 RPM spindle speed), top and bottom attached disk clamps, RVFF sensors, humidity sensors, and other ways to boost reliability and ensure consistent performance. Like other datacenter-grade hard drives, the Ultrastar DC HC550 HDDs are rated for a 550 TB/annual workload, a 2.5 million hours MTBF, and are covered by a five-year limited warranty.


The research and development efforts of the hard drive manufacturers to produce ever-denser storage technology has been well documented. Western Digital, Seagate, and others have been looking at technologies based around temporarily altering the coercivity of the recording media, which is accomplished by applying (additional) energy to a platter while writing. The end result of these efforts has been the development of techniques such as heating the platters (HAMR) or using microwaves on them (MAMR), both of which allow a hard drive head to write smaller sectors. With their similar-yet-different underpinnings, this has lead to the catch-all term Energy-Assissted Magnetic Recording (EAMR) to describe these techniques.

Being a large corporation, Western Digital does not put all of its eggs into one basket, and as a result has been researching several EAMR technologies. This includes HAMR, MAMR, bit-patterned media (BPM), heated-dot magnetic recording (HDMR, BPM+HAMR) and even more advanced technologies.

At some point in 2017, the company seemed to settle on MAMR, announcing a plan to produce MAMR-based HDDs for high-capacity applications. Still, while the company focused on MAMR and, presumably for competitive reasons was publicly downplaying HAMR for a while, WD did not really stop investing in it.

Ultimately, having designed at least two EAMR technologies, Western Digital can now use either of them. Unfortunately, for those competitive (and to some degree political) reasons as before, the manufacturer also doesn't really want to disclose which of those technologies it's using. So while the new Ultrastar DC HC550 HDDs are using some form of an EAMR technology, WD isn't saying whether it's HAMR or MAMR.

As things stand, the only thing that the company has said on the matter is telling that the new drivers do not use a spin-torque oscillator, which is a key element of Western Digital's MAMR technology.

Here is an official statement from Western Digital:

“The 18 TB Ultrastar DC HC550 is the first HDD in the industry using energy assisted recording technology. As part of our MAMR development, we have discovered a variety of energy assisted techniques that boost areal density. For competitive reasons, we are not disclosing specific details about which energy assist technologies are used in each drive.”

With MAMR apparently eliminated, it would seem that WD is using a form of HAMR for the new drives. However at least for the time being, it's not something the company is willing to disclose.

IOPS-per-TB Challenge

Ultimately, whether HAMR or MAMR, the end result is that WD's EAMR tech has allowed them to increase their drive platter density and resulting drive capacities. Density improvements are always particularly welcome, as it should allow the HC550 to offer higher sequential performance than existing 7200 RPM hard drives. However, since the new storage devices feature a single actuator that enables around 80 IOPS random reads, IOPS-per-TB performance of the new units will be lower when compared to currently available high-capacity 10 – 14 TB HDDs (think 4 IOPS-per-TB vs. 5.7 – 8 IOPS-per-TB) and will require operators of large datacenters to tune their hardware and software to guarantee their customers appropriate QoS.

Unlike Westen Digital’s flagship 20 TB shingled magnetic recording (SMR) hard drive for cold storage applications, the company’s 16 TB and 18 TB nearly HDDs use energy-assisted conventional magnetic recording (CMR), which ensures predictable performance both for random read and write operations. As a result, while the Ultrastar DC 650 SMR HDD will be available only to select customers that can mitigate peculiarities of SMR, the Ultrastar DC 550 hard drives will be available to all clients that are satisfied with their IOPS-per-TB performance and will have qualified them in their datacenters.

Samples & Availability

Western Digital will ship samples of its EAMR-based Ultrastar DC HC550 16 TB and 18 TB hard drives to clients late this year and plans to initiate their volume ramp in 2020. One additional thing to note about the 16 TB EAMR-enabled HDDs is that these drives will likely be used primarily for technology validation, as there are commercial 16 TB CMR+TDMR available today that do not need extensive tests by operators of datacenters.

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Source: Western Digital

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  • MFinn3333 - Wednesday, September 18, 2019 - link

    The 1st HDD was the IBM 350 which stores 5 million 6-bit characters (3.75 MB). It was leased at $3,200 a month in September 1957.
  • quiksilvr - Wednesday, September 18, 2019 - link

    September 1956. And that $3200 a month price included the IBM RAMAC 305 computer system as well.
  • azfacea - Wednesday, September 18, 2019 - link

    density per kg or per liter is a meaningless metric for hard drives to improve. ssds are already far better in that. density per dollar is all hard drives have left and it hasnt really improved at all as far as I can tell in nearly 10 years. still 5x cheaper than ssd for cold storage but shrinking fast. will there be hard drives in 10 years ? my money is on NOOOOOO
  • Revolution11 - Wednesday, September 18, 2019 - link

    Except SSD density per dollar is slowing down, isn't it. Performance per dollar is still improving fast but not the price. Flash node scaling stopped around 1x nm, so the industry moved to V-NAND. But with every new layer, it gets harder and harder to fab NAND. There will be a barrier to progress in how many layers of NAND can be stacked due to cost of fabrication at some time.

    You can see this already in effect. The rate of improvement in the price per TB has been slowing down for years. Can SSDs go from 5x the price per TB of hard drives to say, 3x the price per TB? Probably. Will it keep narrowing the gap to 1.5x or lower the price per TB of hard drives? I really doubt it.

    A new storage medium no doubt has the potential to overtake hard drives in cost per bit. I just don't think it will be NAND which is already reaching or has reached the end of several technological paths of progress in the near past and future.
  • azfacea - Thursday, September 19, 2019 - link

    "SSD density per dollar is slowing down" aprat from being incomprehensible its just rubbish nonsense.

    ssd price per gigabyte is nearly halved in two years. u say its slowing down. even if it was its still improving. cost per tb for hdd not so much.

    even u admitted they can get to 3x. at 3x hdd are dead. the more volume is lost for hdd, the more expensive they are because they can't amortize R&D.

    at 3x price per GB. hard drives are down to below 50% their current volume which means probably means they are more expensive.

    SSD is at 8 cents per GB now. they absolutely can and will get to 2 cents (which is lower than enterprise HDD cost)

    at 4 cents per GB hard drives are dead and no1 will pay for new node. in fact this is already happening. the reason HAMR MAMR have taken half a decade is cuz no1 wants to pay to develop them. WD wants to re-invent itself as ssd maker
  • azfacea - Thursday, September 19, 2019 - link

    correction to this part:
    at 3x price per GB. hard drives are down to below 50% their current volume which means probably means they are more expensive.

    at 3x price per GB. hard drives are down to below 50% their current volume which means price per GB has to rise to pay the companies fixed cost. meaning HDD will rise in price
  • ksec - Thursday, September 19, 2019 - link

    >A new storage medium no doubt has the potential to overtake hard drives in cost per bit. I just don't think it will be NAND which is already reaching or has reached the end of several technological paths of progress in the near past and future.

    Um? There is a very clear Roadmap with stacking, right now there is no reason why we cant do 1024 layers if not higher, the only issue is yield. There is also EUV NAND which is on the list of improvement, along with dozens of other technical improvement in the pipeline which will all improves Fab Capacity, Density and cost.

    The TCO calculation also isn't just simply Cost / TB, you will need to factor in speed ( the amount of data increases while speed hasn't in HDD needs to more HDD require to balance I/O ) , power usage and space.

    HDD wont die, but other than Cold storage, NAND is replacing HDD in more places than ever.
  • azfacea - Thursday, September 19, 2019 - link

    "HDD wont die, but other than Cold storage, ...."

    but they will, if they are only limited to cold storage and nothing else. do you think you can sustain the massive operations WD and Seagate have + plus many many part suppliers, because Amazon glacier is still interested ? not a chance.

    ppl said optical won't die when thumb drive and wifi showed up, because "they still had some nice things about them"
  • close - Thursday, September 19, 2019 - link

    @azfacea "ppl said optical won't die"

    And does it look like it's dead to you? Consoles? BluRay? Thumb drives have been around for ~2 decades already and while optical may not be a flourishing sector it's far from being dead.

    Also when "ppl" say some technology will(not) die they are talking about a reasonably near future, not decades. Which makes "ppl" right. But if we're talking decades then everything you praise today will die too (eventually) so you too are wrong.

    So whether "ppl" are right or you are wrong the conclusion is more or less the same. You're wrong. HDDs will be around for a long time, NAND will also die and be slowly (or quickly?) replaced at some point. What's your point?
  • ikjadoon - Monday, September 23, 2019 - link

    Consoles ARE moving away from discs. And Blu-ray players have lost mainstream appeal.

    It'll be slow, but I think optical will have lost any remaining marketshare in less than ten years.

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