Two-Dimensional Magnetic Recording Due in 2017

Two-dimensional magnetic recording (TDMR) is a yet another technology that should help to increase areal density and this is something that Seagate is investing in. The manufacturer believes that TDMR helps to increase areal density by 5% to 10%. Plans were announced several months ago and during the conversation with Mark Re, it was confirmed that Seagate was on track to release its first commercial TDMR-based HDDs in 2017.

TDMR technology enables makers of hard drives to increase the areal density of HDD platters by making tracks narrower and pitches even smaller than they are today. While it is possible to minimize the writer (a part of an HDD's head that writes data), reading becomes a challenge. As magnetic tracks become narrower, they start to affect each other, an effect called magnetic inter-track interference (ITI). This means It becomes increasingly hard for HDD heads (readers) to perform read operations. To mitigate the ITI effect of very narrow tracks, two-dimensional magnetic recording technology uses an array of heads to read data from either one, or several nearby tracks (a method described in several scientific publications). This improves the signal-to-noise ratio delivered to the controller. Several readers enable HDD controllers to determine the correct data based on input from several locations, which implies the need for powerful controllers. More importantly, a number of read heads will be a benefit for HDDs featuring HAMR in the future: heat-assisted recording improves the write process, whereas multiple readers improve the read process. We are also told that with relevant programming, hard drives featuring an array of readers per head can increase the performance of HDDs. This will clearly not make the new hard drives as fast as SSDs, but it will help Seagate’s customers (particularly in the SAS space) to increase the performance of their storage devices. Right now, Seagate does not talk about its plans to use multiple readers in commercial drives because such products are several years out, but considers this a possibility.

Seagate confirmed that TDMR lets HDD makers to increase areal density by up to 10%, which is a noticeable amount compared to typical PMR platters. However, additional capacity does not come free in this case when it comes to computing. An array of heads increases bandwidth requirements for the controller as well as the amount of information that the chip needs to process. As a result, the whole TDMR platform becomes generally expensive: it features multiple arrays of heads, new platters, new motors as well as new controllers. This is why Seagate plans to use it for server applications first sometime in early 2017. Seagate did not confirm whether such HDDs would use both TDMR and helium, but said that virtually all technologies could be mixed and matched to build the right solution for every possible application. Keep in mind that these are plans which are subject to change.

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  • drothgery - Saturday, July 9, 2016 - link

    It's complicated. There's a minimum cost to build any mechanical hard drive, and the cheapest possible flash storage device is cheaper than that. That's why you don't see HDDs in any applications that need less than 128 GB or so anymore. It's just that the marginal cost of additional capacity is lower with hard drives (at least, until you start figuring in complex TCO arguments for data centers with very large amounts of storage).
  • zodiacfml - Sunday, July 10, 2016 - link

    It is almost irrelevant due to economies of scale. Right now, HDD are still comfortable with their scale right now. They have to be scared as it might drop non-linear in a few years; their drives will become more expensive that they will have to produce fewer, larger, archival drives.
  • AnnonymousCoward - Sunday, July 10, 2016 - link

    "almost irrelevant"? HDD's entire play is cost/GB, and there's reason to believe they cost MORE below some capacity.

    "economy of scale" - you mean volume? Samsung already ships >10B memory chips per year, far more than Seagate units.
  • Danvelopment - Sunday, July 10, 2016 - link

    Hard drives will remain as long as price/GB stays well ahead of solid state.

    Seeing as manufacturers have been unwilling to maintain that for the last 4 years, all I can see is a death spiral.

    I bought 3x 2TB HDDs in 2012 for $99NZD each. The current cheapest 2TB HDD is $115. And the cheapest HDD or GB is a 3TB at $156 (slightly more/GB).

    Fark HDD manufacturers. They can't win on performance or reliability against Samsung SSDs, all they can do is win on price but that gap has shrunk so much in four years I don't hold much hope for them without a drastic move. SSDs don't have to reach the same price point to take over, they just need to be close enough when accounting for the performance gap.

    It also doesn't help that they've already lost the density crown and in a much smaller form factor.
  • Bobs_Your_Uncle - Tuesday, July 12, 2016 - link

    Just now (7/12/16 @ 19:17EST) heard on The Nightly Business Report (PBS) that Seagate:
    - announced earnings that exceeded analyst expectations
    - raised their projected income guidance
    - experienced their "best day ever" in the markets (measurement metrics not disclosed)

    ... oh yeah ...

    and Seagate announced that they're eliminating 6,000 jobs ...

    The future is certainly looking rosy ... I guess ...
  • neatfeatguy - Thursday, July 14, 2016 - link

    I hear Seagate is looking to close out a major branch location nearing the end of the year or start of Q1 2017. Location in Shakopee, MN or a China branch (sorry, I didn't get what location in China.....rumor is pointing to MN location so far and as early as start of December has been hinted).

    Makes you wonder how well things can really be going for them - unless this is a restructure to help them stay viable in the every fast changing world of storage technology.
  • truemore - Thursday, July 28, 2016 - link

    So I was having a meeting with one of the large corporate storage providers asking when they thought the "mass change" would happen from HHD to SSD for corporate storage.
    Interestingly even their technology people were surprised, but at the enterprise level the inflection point happened this year for primary storage devices. Given much better TCO over time and vast performance improvement with SSDs they have better short and long term ROI due to a better than expected 40% decrease in price per TB in the past 12 months and the large jump in maximum enterprise SSD size.
    According to their people they are pushing all customers as fast as possible to SSD for all hot, and most warm storage. For them it makes perfect sense since they have very few drives break, arrays can easily be upgraded lowering the number of RFPs per $ sold and the performance increase for the customers is frankly amazing in the enterprise compute environment.
    I wonder how this shift will affect us on the bottom, since large storage providers suck a large portion of the overall storage market. They may be the 600 gorilla that forces the market to make a quick move off of HDDs,
    I would also be curious how the better performance and longer life span of SSDs will hurt SSD/HHD producers over the long haul since there will be much fewer sales over the long term.
  • Gothmoth - Saturday, July 30, 2016 - link

    what i want from HDD´s is REABILITY, REABILITY, REABILITY.

    it can´t be that 10+% o harddrives from seagate die on me in the first 6-8 month.
    i have a small renderfarm at home and 8 sytems with 2-4 harddrives each.

    infant mortality of HDD´s is a real problem. and overall REABILITY seems to be getting worse.
  • Gothmoth - Saturday, July 30, 2016 - link

    sorry i meant RELIABILITY... :-)
  • profquatermass - Monday, August 29, 2016 - link

    Oh the Irony......

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