Original URL: https://www.theregister.co.uk/2013/06/25/wd_shingles_hamr_roadmap/

WD HAMRs down shingles on disk drive road map

What sort of nightmares do CTOs have?

By Joe Fay

Posted in Storage, 25th June 2013 07:35 GMT

Analysis Twenty years ago a myriad of hard drive vendors pushing essentially the same technology fought themselves into oblivion.

Over the coming years the remaining players will be pushing traditional technology to its limits to extend the life of hard disk technology. While the industry is pretty much standardised on perpendicular magnetic recording (PMR) at present, in a couple of years there will be more fundamental hard drive technologies co-existing in the market than there are hard drive vendors.

WD chose Istanbul to sketch out its technology plans earlier this month, with CTO Bill Cain updating us on expected debuts for shingling and heat-assisted magnetic recording (HAMR), and detailing in which storage tiers the technologies are likely to land. He also told us what stops him from sleeping at night.

First up is shingling, which will see more data being crammed onto the platters in disk drives, by overlapping the tracks in which data is written - as with the “shingles” on an American roof. Cain's presentation (see below) showed the technology kicking in around 2014.

wd graphic showing area density

"It sounds like most of the industry is in roughly the same time frame,” he says.

Once OEMs and customers have gotten over the roofing and chickenpox jokes they will have to get to grips with the two different approaches covered by the shingling banner.

Type 1 shingling "fully emulates a traditional drive [with] the shingling done under the covers so you could use that in any kind of a client application so we’re working on products that would be suitable for that."

Type 2 shingling: "instead of hiding from the host the fact that it is an SMR device, it actually is used in an application where the host is aware."

As for what the application is, WD is working with Seagate, Toshiba, and Hitachi, "to better define what that might be".

The firm is also working with key end customers to identify potential applications, with Cain listing "cold storage, archival storage where again the host system being aware of the device and doing some of that management is important."

Asked if that positioned Type 2 shingled drives as a replacement for tape, Cain said, "that’s one of the possibilities. There’s more than just tape replacement you can use it for. It’s for an application that’s probably more sequential writes by nature archival."

He added, "In enterprise systems, predictability of performance is very important - the drives making those tasks visible to the host can end up having a better performance."

HAMR appeared to be slotted in for 2016 according to Cain's slide. "We’re continuing to move along with the technology getting the fundamentals developed. It’s more of a traditional extension of conventional recording that allows us to be able to push the linear and areal density in a more traditional way."

An extension with the slight complication of adding that heating element, which poses more challenges around head reliability.

As for progress to date, Cain said "We’re working on prototype drives that are functioning with that technology [and] making progress towards the productisation. I view that it’s a little bit further out in time and I think that’s consistent with the messaging from rest of the industry."

Of course, once you've invested in a major step in technology, you're going to want to milk that tech for as long as possible. So what do you do if you've made two big steps?

First of all, said Cain, "you can think of shingling as not quite the same as the transition from longitudinal recording to perpendicular recording".

"You could have shingled an LMR drive. We will shingle PMR drives. You can shingle a HAMR drive," said Cain.

"The sequence would be perpendicular [magnetic recording] then we would use shingling in pertinent applications to extend the perpendicular. Then we’ll produce HAMR, to do the same thing.

"I’d say they will coexist for some period of time," he said, giving the vendor plenty of scope for segmenting its products... or at least its marketing.

"For applications that care about the same throughput and that kind of performance attribute then HAMR is definitely the way to go. In other applications where that’s less important and capacity overall is more important than SMR, PMR is probably a better solution," he explained. "Both technologies will be available at a particular capacity point then which technology goes into a particular market segment will depend on those attributes."

Two for Thai

The prospect of multiple manufacturing operations spanning multiple technologies might be considered a headache for any company. All the more for WD, given its manufacturing operation was pretty much crippled when its Thailand plants were inundated during freak floods in 2011.

Cain said, shingling doesn't particularly require any major changes to the manufacturing process or infrastructure.

"HAMR does require the integration of the lasering optics into the recording head and the recording media is a little different material - although the manufacturing tools for those media are the same."

So WD will be relying on its existing Thai operations to underpin the new technologies, though Cain adds that "one of the outcomes of the floods was a little more diversification of the slider operations".

While WD was explicit on the rollout of HAMR and shingling, there was less discussion of where flash fits in. The company has one hybrid drive shipping - the 5mm WD Black - with the flash components sourced through a partnership with Sandisk. While it's in-house at OEMs we’re not currently aware of any shipping product. What happens next is less clear, though it seems Cain sees the challenges in the shape of management software.

"A lot of flash management is in that module. Over time you'll see a higher level of integration and management between the two."

The management issues become more complicated with hybrid shingled drives, Cain explained, where the time penalty associated with rewriting shingled tracks, is offset against the speed the flash cache gives.

“With those decisions about what’s stored where, how we move it around, when the drive’s spun up when it’s not...by integrating that more into the single control point inside the drive we can provide the best overall experience of power and performance."

So if WD sees the hybrid/SSD issue as essentially a management software challenge, this brings up the questions: will Sandisk remain WD's flash partner and how will the dynamics of that “partnership” change over time and will WD second-source or invest in its own flash capability?

On the first, Cain replies, "that’s an evolving strategy and of course [we’re] looking into, as with other components, what the right strategic relationship is." He is similarly opaque on the second point.

So WD is facing the introduction of multiple recording technologies, which will co-exist and overlap, as is targets more segments of the storage market. It also has to continue to work out how its existing magnetic recording business co-exists with solid state storage. And, it hopes, it will at some point really have to get to grips with how it integrates with Hitachi and some of its more esoteric technologies.

All the while it has to worry about traditional hard drive technology maintain its cost performance advantage over other storage technologies.

WD graphic showing performance versus cost

So while extending the life of traditional hard disk and increasing the value it can bring, is it in danger of missing a bolt from the blue - for example in the form of a new entrant to hard disk storage from China say, or, the ultimate nightmare, a completely new storage technology?

On the first, Cain says, "obviously it’s a very capital intensive. It would take lot of IP to be able to manufacture the key technology components.

"We’ve seen more consolidation in the industry over the last five years than diversification. It certainly would be going against the overall trend."

On the second, "Oh sure - nightmare is someone creates something in that upper right hand corner?”

IP could preclude a bolt from the blue to some extent, he says, but "if you talking about something that is completely new and different, and therefore has its own set of IP, without knowing what that is hard to speculate."

So, if this is the stuff of nightmares, does Cain sleep soundly?

A micro-pause. "Sometimes."

Blowing hot air helium down the roadmap

One thing that wasn’t on Cain’s roadmap is helium. That’s because helium appears on Hitachi Global Storage Technology’s roadmap, with products slated for this year which will contain the lighter-than-air inert gas, massively reducing resistance within the drive and allowing the squeezing in of more platters.

But although HGST is part of Western Digital - it isn't quite. Chinese competition authorities ordered that following Western Digital’s acquisition of the Hitachi’s disk drive business, the two companies “hold separate” for two years.

However, WD senior veep and GM of its data centre business, Rich Rutledge, was able to talk about the technology... well, up to a point.

“Helium is part of the long-term roadmap for our industry,” he told us. “Helium will ramp as a percentage between now and 2020.”

As for the technology itself, says Rutledge, it’s already extensively used in disk drive manufacture. The challenge is stopping it leaking from sealed finished products.. “It’s a great example where the physics is well known. It’s the actual engineering and doing it cost effectively at high volume.”

One recurring point from Rutledge was a comparison with Intel. The chip giant makes great play of the R&D and manufacturing resources it can bring to bear and the way beyond microscopic geometries at which it works.

“Our stuff works at similar dimensions to Intel’s stuff. Except it moves. There’s a working sub system in there.”

As Rutledge puts it, WD has "long practised a cost leadership strategy” while Hitachi opted for a “differentiation strategy” being "a little more focused on the high value highly differentiated products” and "very close to a handful of large customers".

Welding these two strategies together will present its own problems. However, because of the Beijing-mandated hold, the new parent has not been able to go in and do a traditional slash-and-burn cost-cutting exercise, but has been forced to think much further ahead.

Rutledge said this will likely lead to a more considered integration in the long term: “We may actually thank the ministry.”