The Evolution of HDDs in the Near Future: Speaking with Seagate CTO, Mark Re
by Anton Shilov on July 6, 2016 2:00 PM ESTTwo-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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nandnandnand - Wednesday, July 6, 2016 - link
They explained how to mitigate SMR performance issues in the article.romrunning - Wednesday, July 6, 2016 - link
Sure, you can try to mitigate the performance, but I feel the initial performance design should have been aiming higher than existing PMR performance. That's why SMR is disappointing to me. I feel like they were dumping R&D into HAMR, and they weren't getting results as fast as they wanted. So they go the SMR route to get the desired results (more storage density) in the interim.It's not like SSDs. While SSDs were lower in capacity initially, the speed increase was dramatically better. SMR-based drives are only slightly better in capacity, but they are more noticeably worse in performance. Thus it didn't have the same impact - it doesn't have enough of the "wow" speed factor to help overlook its performance shortcomings.
It's like when Honda introduced the new Insight hybrid. It wasn't better or even at the same level of "MPG" as the Prius; that's why it didn't fare well.
JimmiG - Thursday, July 7, 2016 - link
Well, SMR is a stopgap solution, but it's here now and it works. HAMR sounds great on paper, but show me where I can buy an 8 TB HAMR drive today, for under $250?My 8TB Seagate Archive has the lowest cost/GB of any drive at the time, and it works fine as a secondary storage/backup drive. Just manually dumping files to it or running scheduled backups work great, with performance that doesn't really "feel" any different than my 5900 RPM 4 TB PMR drive.
romrunning - Wednesday, July 6, 2016 - link
I also say this coming from someone who liked the Seagate 600 Pro SSD. They could have done a lot more years ago to compete for the market lead in consumer SSDs; basically Samsung dominates right now.StormyParis - Wednesday, July 6, 2016 - link
Even as an individuaI, I mostly don't care about storage performance. OS and apps and "live" data files get an SSD. That <5% of my storage. Media, archives and backups get an HDD. That's >95% of my storage. I don't care about performance for SSD nor HDD, both are OK for the uses I dedicate them too even in their cheapest crappiest incarnations.I'm more interested in cost, space, reliability, and durability.
serendip - Friday, July 8, 2016 - link
Amen to that, beyond the tiny but vocal enthusiast community there are loads of users who want cheap, huge and reliable storage. I hope the SSD and HDD manufacturers don't forget this market and just concentrate on enthusiasts or enterprise customers.paulemannsen - Saturday, July 9, 2016 - link
+1. I could even live with 10/10 mb read/write speeds, just give me more reliability and space.Nozuka - Wednesday, July 6, 2016 - link
There are already 13TB SSDs... currently extremely expensive, but it's only a matter of time...XZerg - Wednesday, July 6, 2016 - link
you mean 16TB - from Samsung - http://gizmodo.com/samsungs-16tb-ssd-is-now-an-act...Lolimaster - Friday, July 8, 2016 - link
The 13TB was from fixstars (japan based). They were the 1st in multiterabyte SSDs 3-6-10-13TB.