Unless Toshiba knows MS will be adding the feature to its generic NVME driver in the near future, not providing a driver of their own is an insane footgun.
One issue that I see with the HMD is that, what if the machine loses power? The HMD won't be able to flush data to the SSD.
On the other hand, I could see that the HMD could be quite large compared to other SSD's on board DRAM. But then again it would take space that could be used as the OS's disk cache...
The power loss concerns are probably why Toshiba is using the HMB only as a read cache. And they're not using much DRAM since they're not storing user data in the DRAM and are just caching a subset of the NAND mapping tables.
Normal consumer SSDs of any type don't have the capacitors needed to flush their caches in the event of power loss; so these aren't any more vulnerable than the rest of the non-enterprise drives on the market.
True and irrelevant to what I said. Unless you're paying extra for an enterprise class drive, most SSDs don't have capacitors for their onboard ram either. Using system ram is no worse than the status quo on consumer SSDs with onboard ram. In both cases unexpected power loss will cost whatever is in the write cache.
BGA SSDs are probably intended for use in mobile devices that contain internal batteries and are largely protected from power losses under normal operation. Besides that, like Billy said, HMB isn't caching data that needs to be written to flash.
this product looks at least 3 years behind what samsung offers. last month they announced a 512GB BGA NVME SSD with the controller, Nand and DRAM all in a smaller package than this.
The Samsung PM971 uses the same 16x20 mm BGA interface as Toshiba's BG series. They're two different product tiers in the same space. The Toshiba solution, being DRAM-less and using TLC, will probably be quite a bit cheaper to account for its lower performance.
Hopefully we will see those laptops that currently come with 16-64GB of UFS/eMMC flash storage (Chromebooks, etc) move onto 128GB NVMe drives next year.
Cool, HMB essentially turns these devices into FusionIO cards: Those guys put the brains into the host where there is tons more of CPU power and RAM than on the device itself.
The result was the fastest Flash drives on the market as well as a native API which would allow you to use Flash not just as a block device, but a e.g. a persistent key-value store.
And of course, there was no such thing as a 16 or 32 entry command queue, which really can slow down things on Flash, when you have some major reorganization going on.
Of course it came at the price of not being bootable, having to compile drivers for every OS (and release) etc.
So here we have a hybrid, which can boot stupid, using the mapping tables embedded on the device but then recreate and maintains a read-only copy on the host to speed up block directory lookups.
I'm guessing that they won't actually update block directories on each block write on the device itself, because even with a rotating log (to cut down on erase block write amplification) you'd still have the rather large Flash write blocks.
But if the data blocks themselves contain enough metadata to recreate the block directory in case of a powerloss crash, that should basically work out.
Then again, even without external DRAM, the controller itself could cache some directory blocks and flush them with the help of some hold-up power-caps to the Flash.
I like it and so would Steve Wozniak, I guess! It's so much like nibbles instead or MFM... (showing my age here)
We’ve updated our terms. By continuing to use the site and/or by logging into your account, you agree to the Site’s updated Terms of Use and Privacy Policy.
14 Comments
Back to Article
DanNeely - Wednesday, August 3, 2016 - link
Unless Toshiba knows MS will be adding the feature to its generic NVME driver in the near future, not providing a driver of their own is an insane footgun.ddriver - Thursday, August 4, 2016 - link
I bet they will only offer drivers for that adware/spyware w10...asdacap - Wednesday, August 3, 2016 - link
One issue that I see with the HMD is that, what if the machine loses power? The HMD won't be able to flush data to the SSD.On the other hand, I could see that the HMD could be quite large compared to other SSD's on board DRAM. But then again it would take space that could be used as the OS's disk cache...
Billy Tallis - Wednesday, August 3, 2016 - link
The power loss concerns are probably why Toshiba is using the HMB only as a read cache. And they're not using much DRAM since they're not storing user data in the DRAM and are just caching a subset of the NAND mapping tables.DanNeely - Wednesday, August 3, 2016 - link
Normal consumer SSDs of any type don't have the capacitors needed to flush their caches in the event of power loss; so these aren't any more vulnerable than the rest of the non-enterprise drives on the market.ddriver - Thursday, August 4, 2016 - link
Capacitors on the SSD will do you NO good when your cache is not on the SSD but in system ram.DanNeely - Thursday, August 4, 2016 - link
True and irrelevant to what I said. Unless you're paying extra for an enterprise class drive, most SSDs don't have capacitors for their onboard ram either. Using system ram is no worse than the status quo on consumer SSDs with onboard ram. In both cases unexpected power loss will cost whatever is in the write cache.mapesdhs - Saturday, August 6, 2016 - link
Some consumer drives do have it, eg. Crucial M550.Always surprised me that Samsung's Pro series never had it though.
BrokenCrayons - Thursday, August 4, 2016 - link
BGA SSDs are probably intended for use in mobile devices that contain internal batteries and are largely protected from power losses under normal operation. Besides that, like Billy said, HMB isn't caching data that needs to be written to flash.Morawka - Wednesday, August 3, 2016 - link
this product looks at least 3 years behind what samsung offers. last month they announced a 512GB BGA NVME SSD with the controller, Nand and DRAM all in a smaller package than this.Billy Tallis - Wednesday, August 3, 2016 - link
The Samsung PM971 uses the same 16x20 mm BGA interface as Toshiba's BG series. They're two different product tiers in the same space. The Toshiba solution, being DRAM-less and using TLC, will probably be quite a bit cheaper to account for its lower performance.Morawka - Thursday, August 4, 2016 - link
half the capacity, no dram, slower nand, Less endurance, Taller z Height, it better be cheaper.psychobriggsy - Thursday, August 4, 2016 - link
Hopefully we will see those laptops that currently come with 16-64GB of UFS/eMMC flash storage (Chromebooks, etc) move onto 128GB NVMe drives next year.abufrejoval - Thursday, August 4, 2016 - link
Cool, HMB essentially turns these devices into FusionIO cards: Those guys put the brains into the host where there is tons more of CPU power and RAM than on the device itself.The result was the fastest Flash drives on the market as well as a native API which would allow you to use Flash not just as a block device, but a e.g. a persistent key-value store.
And of course, there was no such thing as a 16 or 32 entry command queue, which really can slow down things on Flash, when you have some major reorganization going on.
Of course it came at the price of not being bootable, having to compile drivers for every OS (and release) etc.
So here we have a hybrid, which can boot stupid, using the mapping tables embedded on the device but then recreate and maintains a read-only copy on the host to speed up block directory lookups.
I'm guessing that they won't actually update block directories on each block write on the device itself, because even with a rotating log (to cut down on erase block write amplification) you'd still have the rather large Flash write blocks.
But if the data blocks themselves contain enough metadata to recreate the block directory in case of a powerloss crash, that should basically work out.
Then again, even without external DRAM, the controller itself could cache some directory blocks and flush them with the help of some hold-up power-caps to the Flash.
I like it and so would Steve Wozniak, I guess! It's so much like nibbles instead or MFM... (showing my age here)