HGST has said "no" to hybrids, it would seem. While Seagate, Toshiba and WD are all pushing the idea of hybrid drives, SSHDs, with a flash cache added to the spinning disks, HGST prefers a different approach: separate flash and disk drives. HGST, the wholly owned but separately operating subsidiary of Western Digital, has a …
What he says is all well and good for OEMs building new machines but for someone wanting a replacement drive for an existing laptop the hybrid design offers a drop in upgrade. Most laptops don't have a spare SATA or PCI-E slot for a flash drive to plug in.
"What he says is all well and good "...
but even that didn't sound convincing - the parallel interfaces of separate storage volumes is largely irrelevant when you're primarily caching data between the two volumes on a client device. Add in that the system integrators won't select best of breed, they'll select cheapest of breed, and the fact that a dedicated processor need not be inferior to sharing the CPU (eg RAID is always better with a dedicated processor rather than software RAID), and his arguments are worn very thin.
This looks to me more like HGST were late to the hybrid device party (or won't licence essential patents), and are now trying to excuse their omission. Certainly, a caching SSD volume (or programme volume) in a desktop accompanied by a big spinning rust drive is probably the best upgrade for many users, and the two drive solution is the way to go, but in a laptop then hybrids make an excellent solution. Was he paid for getting it @rse about face like this?
This looks to me more like HGST isn't bothering with hybrids because WD is already doing it, just as WD isn't bothering with helium because HGST is already working on it.
China may have ordered them to operate separately, but that applied primarily to their existing product lines. It didn't order them to act as if the other party didn't exist and an eventual merger wouldn't happen. Given that, it makes strategic sense not to duplicate efforts, especially in those cases where the other party already has a leg up.
My thought also: WD and HGST will merge, so duplicating research is pointless. Hydrid drives is WD's job.
As for "robust device drivers" I understand what he is saying. A modern CPU is more powerful than the microcontroller in a hard drive, especially when it comes to algorithms that can't be accelerated by custom hardware. So letting an OS combine an SSD-based cache with conventional disk drives may be the best-performing solution. However, it does require someone to write that driver and to support it. (Is it a hint that post-merger, HGST may be getting into the software business? )
The nice thing about a hybrid drive is that you know exactly who to blame if it mangles your data. I feel pretty confident that the caching in hybrid drives will be robust and reliable, even if it's far from optimal for any particular usage pattern .
I just choked on my morning coffee
"and the caching algorithm is being managed by a robust software driver "
That, in an OEM context? If oxymorons gave you wings this would have broken the speed of light barrier and gone to warp 9 on it's own accord. No thanks, no "more "robust drivers" please.
Re: I just choked on my morning coffee
I haven't read any horror stories about OSX's Logical Volume Manager since it came out nine months ago...
Re: I just choked on my morning coffee
Yeah, but on OS X the potential performance problems that can arise from putting the wrong kind of data on the wrong disk (yes HDDs can be faster than SSDs for certain access patterns) are largely masked by the already horrendous performance of HFS+.
"SSHD's dingle interface"
Childish snort time! He said "dingle"! Tee-hee-hee!
Better done at the OS level
The semantics of block devices are not rich enough for them to do a good job of caching. This is better done at the OS' filesystem layer, as with ZFS' logzilla/cachezilla hybrid storage pool approach, Apple's Fusion or Microsoft's ReadyBoost.
translation: they don't have the software
There are obvious use cases for hybrid drives at the hardware level. form factor being one, you can slap a hybrid drive into pretty much any laptop out there and get an immediate speed boost. No need go and buy a new laptop. Easy to support is another - my Linux distribution(Ubuntu 10.04 LTS) has no support for hybrid on my laptop or desktop. Not sure what the state is of hybrid on Linux in newer systems, haven't seen much talk of it.
Simplicity - no special software to manage/patch/etc.
So far all of the hybrid drives have come with very small SSDs, so the only obvious advantage I see to splitting it is being able to have a much larger cache.
It seems Hitachi lacks the software/firmware tech to do hybrid so they are talking the approach down, when it is clearly a winning solution in many cases(I'd wager the majority of cases).
I've used Seagate Momentus XT for probably two years now and it provides an enormous speed boost on both laptop(8GB ram) and desktop(16GB ram). I have seen people say the hybrids don't do anything over memory cache, well my experience says otherwise. If firefox is cached in the hybrid I can start it in less than a second, if it is cached in memory(start it, shut it down, start it again) it still takes several seconds.
The only downsides I have to them are the SSD cache is small, and when dual booting(though rare for me) it wrecks havoc with the cache, which has to get warmed up again. No worse than memory cache which has to get warmed up regardless.
I much prefer Hitachi's approach, but for other reasons than he mentioned
With a separate SSD and HDD, I can upgrade them independently.
Then I can throw out the "robust caching software" after upgrading the SSD part from say,30GB to 256GB like on the Asus UX32VD, and thus arrive at the true "optimal" solution of having an SSD for OS and Software and an HDD for data that doesn't get thrashed by Windows.
Asus and Gigabyte have shown that you can easily fit this type of combo into an Ultrabook, since mSata or M.2 flash drives are already being built in a form factor matching that of a gum stick.
This is my primary criterion for selecting an Ultrabook, right next to getting a high brightness IPS display.
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