7-bits per cell, great... I guess this means that soon our SSDs' write performance will barely match that of the old 3.5" floppy drives while only allowing 5 power-erase cycles before dying.
That might be how it is used initially, but can we really trust manufacturers to not use it for normal SSDs? They could certainly claim high capacity to the uninformed masses. They're already pushing some questionable QLC based drives into the market. I remember Anandtech reviewing one that had HDD write levels of performance.
I did read the article, congrats on being an asshole.
We have seen the trend for years now. Every time they increase the number of bits-per cell, it is only a matter of time before that that tech is used in all consumer SSDs. We have seen this with SLC, MLC, TLC and we are starting the process of transitioning to QLC. I remember when it was claimed that QLC would only be used for write once read multiple times scenarios. That sure did not last, so why would you think otherwise here?
> That sure did not last, so why would you think otherwise here?
Because, when you get down into the details, they're talking about effectively 4-bits per cell on 40 nm technology.
I think the 7 bpc was a stunt meant to grab headlines, because the node it used was never specified. Either that, or they actually *did* say what node it was, and the article is at fault for failing to report it. I wouldn't be surprised if it was something truly archaic, of the sort that's cheap enough for small-batch university research projects.
I was recently looking askance at Crucial's 4 TB refresh of their MX500. However, I found a review that went into considerable depth about Micron's shift in cell architecture and came away with the impression that endurance of their latest TLC memory could actually be somewhat comparable to their old MLC stuff. Not sure if that's accurate, but they've certainly regained some ground.
It's accurate. The TLC Samsung 980 Pro has the same TBW as the MLC 950 Pro and wipes the floor with it on all other parameters, at 25% of the GB price of a 950 Pro in 2016. Not to mention the vast majority of usecases will never wear out a TLC or even a QLC SSD and if your needs are beyond that you're now part of a very small market for which properly spec'ed professional parts exist and you should be aware of that.
P/E is Program/Erase, lol. The slowdown isn't logarithmic. It won't be floppy speed, or even SMR HDD speed. The main problem will almost certainly be that the energy cost per MB transferred will be higher, which will prevent Mobile adoption, which will seriously hamper scaling because that is where scaling starts. I suspect this is part of why their MCU efforts are at QLC, albeit there's low-power synergy with 2 cells = 8 bits as well. As for P/E, the article claims 100k P/E cycles. That's probably for when it's operating in SLC mode at 40nm. Generally you divide by 3 each time you add a level, so 100k / 3^7 is approx 45 7-layer P/E cycles, which is probably still OK for consumer-level photography memory. However only 10 years of retention when it's damn near an archival format... that is sucky and again will harm adoption and scaling. So for those reasons I suspect this will be dead in the water.
Maybe someone can elaborate, at what amount *read* rate on stored data (equal read address for longer period compared to writing cells with addresses being available empty pages) is impacting voltage drift? Thx
if this (https://media.springernature.com/lw785/springer-st... would be reference for 5V power supply voltage nand storage system (compared to 1.8V nand power supply, etc.) and told 5-6% deviation for slc comparable 1bit level storage voltage_th (threshold) is limit for reliable avoidance of bit error rate above acceptable rate, then voltage level for acceptable recognition for 0/1 of storage state is limited to about 0.2-0.25V deviation from reference voltage for each state (0V or maybe slightly below GND, 4-4.2V for a logical 1). These 5-6% are divided by 4 on MLC, div by 8 on TLC, /16 on QLC and /128 on 7bit level storage cell, what given relatively high 5V device supply might get into 1.9mV for limit of deviation from reference voltage for reliable recognition of cell state and stored bit data? Seen 0.15V drift for a 40days data retention time on room temperatures (P3 testing conditions: https://www.researchgate.net/profile/Onur-Mutlu-4/... 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 ), this 10yrs retention time is the real progress and news for this? Still interested, what read rate is affecting cells voltage treshold and how does storage management invisibly to users monitoring statistics (and tools) refreshes cells in reaction to amount of read capacity leakages to cell gates?
Sorry, linking to graphs was not like intended: if this ( https://rb.gy/youkdw ) would be reference for 5V power supply voltage nand storage system (instead of compared to 1.8V nand power supply, etc.) and told 5-6% deviation for slc comparable 1bit level storage voltage_th (threshold) is limit for reliable avoidance of bit error rate above acceptable rate, then voltage level for acceptable recognition for 0/1 of storage state is limited to about 0.2-0.25V deviation from reference voltage for each state (0V or maybe slightly below GND, ~4-4.2V for a logical 1). These 5-6% for slc high state, are divided by 4 on MLC, div by 8 on TLC, /16 on QLC and /128 on 7bit level storage cell, what, given relatively high 5V device supply, might get into 1.9mV for limit of deviation from reference voltage for reliable recognition of cell state and stored bit data? Seen 0.15V drift for a 40days data retention time on room temperatures (P3 testing conditions: https://rb.gy/eebjgg,https://rb.gy/sbush0 ), this 10yrs retention time is the real progress and news for this? Still interested, what read rate is affecting cells voltage treshold and how does storage management invisibly to users monitoring statistics (and tools) refreshes cells in reaction to amount of read capacity leakages to cell gates?
While for MLC cells it was mentioned, there could be a degradation with read accesses, resulting into higher demand for data refresh write for about 1 million reads on SLC compared to 100k-20k reads on MLC cells, data for TLC or QLC are rare. Samsung (for e.g. 845DC EVO 3-bit MLC read intensive, 850DC PRO 2-bit, 24-layer MLC NAND mixed and write intensive) advertises for read intensive use cases "Read-intensive use cases are typical of presentation platforms such as web servers, social media hosts, search engines and content- delivery networks. Data is written once, tagged and categorized, updated infrequently if ever, and read on-demand by millions of users. Planar NaND has excellent read performance, and limiting the number of writes extends the longevity of an SSD using it."
retention for MLC (2012, some overview, page 7) https://citeseerx.ist.psu.edu/viewdoc/download?doi... SLC (P/E cycles) with varying recovery in seconds from programming (~100's) ~63yrs, (100's-1000's) ~20yrs MLC (~100's) ~20yrs, (~1000's) ~5yrs (also varying with prog. recovery from none/10s to 10000s/1d, with x10-x100 factor difference between for P/E cycles allowed for accepted retention needs, page 8 diagrams, and about x10 factor between SLC and 2-bit MLC NAND type, but absolute 1/2-1/3 data retention periods (years on 100's P/E) for MLC's on 2012 knowlegde and tech, just for overview on retention development and request for TLC/QLC/'7-bit'LC data and studies)
3d-V-NAND (>2013, vs. planar 2d NAND) improved cell performance (page 12), more evenly distributed 'natural' voltage threshold, reduced cell coupling (on read/write ?), a 950 PRO's CTF (Charge Trap Flash) technology is advertised like nearly interference-free, wrt to cell coupling and therefore improve longevity and retention performance (?) https://downloadcenter.samsung.com/content/UM/2017...
Considering 3d-Xpoint (Intel) there's 'fewer' information about data retention, but some (most) on cell performance (high IOPS for random r/w, write-in-place tech) and (r/)w endurance (TBW ~10x TLC-NAND types and P/E <=1billion-10million).
2016/2017 review of Xpoint tech (& Micron QuantX) "Current 2D NAND is already below a dozen electrons per cell, and even 3D NAND will encounter scaling limitations as lithographies shrink." https://www.tomshardware.com/reviews/3d-xpoint-gui...
BTW, did read about '10 years retention time on 150°C' (PCM for enhanced data storage times, A. Redaelli, Ed., Phase Change Memory), what seem being a necessity (standard) for automotive devices/tasks.
data retention for 3DXP (3d-Xpoint) for client or enterprise flash storage devices ?
I have an old, NVME 1.0 Intel SSD that's probably MLC. Its datasheet said the same thing about a 3 month limit for power-off data retention, but I've left it powered off for probably close to 6 months at a time and lost nothing. I think that's just their minimum guarantee. I use BTRFS, which maintains per-block checksums that enable me to be fairly certain no (uncorrectable) bit-fade occurred.
researching was more about learning how flash cells technology improved and reality is better experience than theoretical limits, yes read endurance is some research work, but what to learn (common knowledge) for new consumer devices on QLC (2022) technology (different from professionals enterprise/datacenter storage devices and (data) maintenance knowledge)? People (did) change from HDDs towards SSDs ...
This is true, but high endurance in extreme conditions can often imply extreme endurance in normal conditions. See also: the recent scandal about extreme-cold steel tests for US submarines.
"The company says that a standard modern memory cell with this level of control would only be able to retail the data for around 100 seconds,..." "retain", not "retail": "The company says that a standard modern memory cell with this level of control would only be able to retain the data for around 100 seconds,..."
As soon as I saw 7 BPC, I knew it wasn't going to be manufactured in any kind of advanced process. To be able to reliably store enough electrons to even be able to tell apart 128 different voltage levels, you'd physically need a large area--especially with the insulation thickness you'd need to get that 10y at 150C retention. Then they mentioned using it in microcontrollers and similar applications at 40nm and I was all "...and there it is."
Might as well lump this in with FERAM and similar technologies that only make sense in very constrained applications.
Form 1-bit to 2-bit I need 100% more bits, and double the capacity at the same time, from 1 state I can store 2 states. From 2-bit to 3-bit I only need 50% more bits, but still double the capacity, instead of 2 states I can store 4 states. From 3-bit to 4-bit I only need 25% more bits, but again double the capacity, instead of 4 states I can store 8 states now. .... So in case of 7-bit I can store 128 states (the reason I need to distinguish 128 voltage levels). So the point of the article is totally wrong. The more bits I add the cheaper it gets.
> From 2-bit to 3-bit I only need 50% more bits, but still double the capacity, > instead of 2 states I can store 4 states.
Doubling the number of states doesn't equate to doubling the storage capacity. I don't know what else to say, other than maybe try reading about information theory and some of it'll start to sink in?
> So the point of the article is totally wrong. The more bits I add the cheaper it gets.
I think that point isn't lost on anyone. The issue is that the incremental benefit of each further bit grows less and less. At some point, it's not worth the tradeoffs that come with packing more bits per cell.
As I was reading this, I got to wondering... does anyone know if conventional NAND does anything like storing a "full" cell per block, as a reference charge? When reading the block, you could use that to calibrate the ADC, essentially normalizing out the voltage drop due to charge leakage.
I'm not a physicist or electrical engineering person, but I assume voltage drift would occur statistically randomly. I.e. something that lets you determine in advance the average drift of a bunch of cells, but not the particular drift of a particular cell.
Surprisingly, I managed to copy and paste it to a file, then base64 -d and get an *almost* valid JPG file. I'm just missing the X-axis label in your graph.
possible also, inserting from data:image/jpeg;base64,/9j/4AAQSkZ...31KRFKUpE/9k= into browser address line (url for uniform resource identifier) ( links without colons or bracket are functional also )
I am wondering if they are ever going to go to some number of levels which isn't a power of two. For instance you might be better off going from 16 levels to 25 levels instead of 32 levels, particularly if you are tuning dynamically for performance, persistence, device aging, etc.
At the block level I don't see any problem being non-binary because you can arithmetic code your data. I know it is hard to parallelize but it doesn't seem too hard if you could lean on the main CPU instead of depending on inferior silicon in the device or put some small, specialized and fast-clocked chiplet into the device.
> wondering if they are ever going to go to some number of levels which isn't a power of two.
It might come to that, if 5-bit cells prove too challenging.
> At the block level I don't see any problem being non-binary
Yeah, I think that's not the main issue. As the article pointed out, the benefit of each additional bit per cell decreases exponentially, yet the tradeoffs are real. Once you start adding *fractions* of a bit per cell, the upside is even smaller. Maybe for like bottom-tier NAND, used in the lowest-margin products, it might still be worthwhile.
Another doubt I have is about the ADC technology you'd need to use. Naively, I think you'd need at least a 6-bit ADC to recover 4.5 bits of information per cell. However, maybe there's some way to build a non- base-2 ADC that would be more cost-effective.
I’m guessing that the vast majority of data on SSD is actually static data that rarely changes from month to month (or even year to year).
I wouldn’t mind an 8 TB m.2 drive where 4 or 6 TB is ultra cheap low cycle 7-bit storage, and 2-4 TB is faster / more durable SLC or MLC. Of course that requires more intelligent tiered storage monitoring brains on the m.2 drive but it seems feasible.
I don’t fully understand how it works but many modern nvme SSDs shift their storage between SLC / TLC / QLC as needed so if it’s possible to extend that further, I’d be happy with a nvme drive that shifted its storage space between 7+-bit long term storage and SLC as needed. Yes this means the capacity varies dynamically - this already happens behind the scenes with modern SSDs. Also over time some cells might become too degraded to be available for 7+-bit storage. They can just be redesigated as permanent SLC (or xLC) cells.
with customers getting information about wear leveling, TBW (with smart output) and long term storage capabilities of currently available flash cells within storage devices? Easy example: How does one get wear information on sdxc or sduc (<=128TB, ~GB/s) secure digital cards?
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48 Comments
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vlad42 - Wednesday, December 15, 2021 - link
7-bits per cell, great...I guess this means that soon our SSDs' write performance will barely match that of the old 3.5" floppy drives while only allowing 5 power-erase cycles before dying.
Drkrieger01 - Wednesday, December 15, 2021 - link
Wow... someone didn't even read the article, just commented on the title.Wrs - Thursday, December 16, 2021 - link
It's getting used as PROM, like a BIOS chip, not like disk storage.vlad42 - Thursday, December 16, 2021 - link
That might be how it is used initially, but can we really trust manufacturers to not use it for normal SSDs? They could certainly claim high capacity to the uninformed masses. They're already pushing some questionable QLC based drives into the market. I remember Anandtech reviewing one that had HDD write levels of performance.Samus - Saturday, December 18, 2021 - link
Trust manufacturers? Let the market decide what products fail.Alexvrb - Sunday, January 2, 2022 - link
We've worked so hard in secret... the time has finally come... to resurrect the Maxtor brand.mode_13h - Monday, January 3, 2022 - link
LOL. Maxtor HDDs actually used to be good, once upon a time.vlad42 - Thursday, December 16, 2021 - link
I did read the article, congrats on being an asshole.We have seen the trend for years now. Every time they increase the number of bits-per cell, it is only a matter of time before that that tech is used in all consumer SSDs. We have seen this with SLC, MLC, TLC and we are starting the process of transitioning to QLC. I remember when it was claimed that QLC would only be used for write once read multiple times scenarios. That sure did not last, so why would you think otherwise here?
mode_13h - Saturday, December 18, 2021 - link
> That sure did not last, so why would you think otherwise here?Because, when you get down into the details, they're talking about effectively 4-bits per cell on 40 nm technology.
I think the 7 bpc was a stunt meant to grab headlines, because the node it used was never specified. Either that, or they actually *did* say what node it was, and the article is at fault for failing to report it. I wouldn't be surprised if it was something truly archaic, of the sort that's cheap enough for small-batch university research projects.
yetanotherhuman - Monday, December 20, 2021 - link
The last SSD I bought was MLC, which is hard to find these days, and very expensive. I see TLC as game-drive quality at best, QLC is just e-waste.mode_13h - Monday, December 20, 2021 - link
I was recently looking askance at Crucial's 4 TB refresh of their MX500. However, I found a review that went into considerable depth about Micron's shift in cell architecture and came away with the impression that endurance of their latest TLC memory could actually be somewhat comparable to their old MLC stuff. Not sure if that's accurate, but they've certainly regained some ground.Kvaern1 - Sunday, January 2, 2022 - link
It's accurate.The TLC Samsung 980 Pro has the same TBW as the MLC 950 Pro and wipes the floor with it on all other parameters, at 25% of the GB price of a 950 Pro in 2016.
Not to mention the vast majority of usecases will never wear out a TLC or even a QLC SSD and if your needs are beyond that you're now part of a very small market for which properly spec'ed professional parts exist and you should be aware of that.
linuxgeex - Wednesday, December 15, 2021 - link
P/E is Program/Erase, lol. The slowdown isn't logarithmic. It won't be floppy speed, or even SMR HDD speed. The main problem will almost certainly be that the energy cost per MB transferred will be higher, which will prevent Mobile adoption, which will seriously hamper scaling because that is where scaling starts. I suspect this is part of why their MCU efforts are at QLC, albeit there's low-power synergy with 2 cells = 8 bits as well. As for P/E, the article claims 100k P/E cycles. That's probably for when it's operating in SLC mode at 40nm. Generally you divide by 3 each time you add a level, so 100k / 3^7 is approx 45 7-layer P/E cycles, which is probably still OK for consumer-level photography memory. However only 10 years of retention when it's damn near an archival format... that is sucky and again will harm adoption and scaling. So for those reasons I suspect this will be dead in the water.vlad42 - Thursday, December 16, 2021 - link
Yeah, P/E was a derp moment with no edit button. I realized the mistake right after hitting reply.Floppy speed was definitely meant as a hyperbole. I hope you are right that that this remains a niche product.
back2future - Friday, December 17, 2021 - link
"repeated read/writes to a high capacity cell will make that voltage drift until the cell is unusable"That's the difference to previous nand cells?
back2future - Sunday, December 19, 2021 - link
Maybe someone can elaborate, at what amount *read* rate on stored data (equal read address for longer period compared to writing cells with addresses being available empty pages) is impacting voltage drift? Thxback2future - Sunday, December 19, 2021 - link
if this (https://media.springernature.com/lw785/springer-st... would be reference for 5V power supply voltage nand storage system (compared to 1.8V nand power supply, etc.) and told 5-6% deviation for slc comparable 1bit level storage voltage_th (threshold) is limit for reliable avoidance of bit error rate above acceptable rate, then voltage level for acceptable recognition for 0/1 of storage state is limited to about 0.2-0.25V deviation from reference voltage for each state (0V or maybe slightly below GND, 4-4.2V for a logical 1).These 5-6% are divided by 4 on MLC, div by 8 on TLC, /16 on QLC and /128 on 7bit level storage cell, what given relatively high 5V device supply might get into 1.9mV for limit of deviation from reference voltage for reliable recognition of cell state and stored bit data? Seen 0.15V drift for a 40days data retention time on room temperatures (P3 testing conditions: https://www.researchgate.net/profile/Onur-Mutlu-4/... 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 ), this 10yrs retention time is the real progress and news for this? Still interested, what read rate is affecting cells voltage treshold and how does storage management invisibly to users monitoring statistics (and tools) refreshes cells in reaction to amount of read capacity leakages to cell gates?
back2future - Sunday, December 19, 2021 - link
Sorry, linking to graphs was not like intended:if this ( https://rb.gy/youkdw ) would be reference for 5V power supply voltage nand storage system (instead of compared to 1.8V nand power supply, etc.) and told 5-6% deviation for slc comparable 1bit level storage voltage_th (threshold) is limit for reliable avoidance of bit error rate above acceptable rate, then voltage level for acceptable recognition for 0/1 of storage state is limited to about 0.2-0.25V deviation from reference voltage for each state (0V or maybe slightly below GND, ~4-4.2V for a logical 1).
These 5-6% for slc high state, are divided by 4 on MLC, div by 8 on TLC, /16 on QLC and /128 on 7bit level storage cell, what, given relatively high 5V device supply, might get into 1.9mV for limit of deviation from reference voltage for reliable recognition of cell state and stored bit data? Seen 0.15V drift for a 40days data retention time on room temperatures (P3 testing conditions: https://rb.gy/eebjgg, https://rb.gy/sbush0 ), this 10yrs retention time is the real progress and news for this? Still interested, what read rate is affecting cells voltage treshold and how does storage management invisibly to users monitoring statistics (and tools) refreshes cells in reaction to amount of read capacity leakages to cell gates?
back2future - Monday, January 3, 2022 - link
While for MLC cells it was mentioned, there could be a degradation with read accesses, resulting into higher demand for data refresh write for about 1 million reads on SLC compared to 100k-20k reads on MLC cells, data for TLC or QLC are rare. Samsung (for e.g. 845DC EVO 3-bit MLC read intensive, 850DC PRO 2-bit, 24-layer MLC NAND mixed and write intensive) advertises for read intensive use cases"Read-intensive use cases are
typical of presentation platforms
such as web servers, social media
hosts, search engines and content-
delivery networks. Data is written
once, tagged and categorized,
updated infrequently if ever, and
read on-demand by millions of
users. Planar NaND has excellent
read performance, and limiting
the number of writes extends the
longevity of an SSD using it."
with mixed loading for read/write on 50/50 to 70/30 assumptions.
https://downloadcenter.samsung.com/content/UM/2017...
details on endurance (retention?)
https://downloadcenter.samsung.com/content/UM/2017...
datacenters failed storage SSDs, parameters for accurate failure identification, table 5 (page 8)
https://www.microsoft.com/en-us/research/wp-conten...
back2future - Monday, January 3, 2022 - link
retention for MLC (2012, some overview, page 7)https://citeseerx.ist.psu.edu/viewdoc/download?doi...
SLC (P/E cycles) with varying recovery in seconds from programming (~100's) ~63yrs, (100's-1000's) ~20yrs
MLC (~100's) ~20yrs, (~1000's) ~5yrs (also varying with prog. recovery from none/10s to 10000s/1d, with x10-x100 factor difference between for P/E cycles allowed for accepted retention needs, page 8 diagrams, and about x10 factor between SLC and 2-bit MLC NAND type, but absolute 1/2-1/3 data retention periods (years on 100's P/E) for MLC's on 2012 knowlegde and tech, just for overview on retention development and request for TLC/QLC/'7-bit'LC data and studies)
back2future - Monday, January 3, 2022 - link
3d-V-NAND (>2013, vs. planar 2d NAND) improved cell performance (page 12),more evenly distributed 'natural' voltage threshold, reduced cell coupling (on read/write ?),
a 950 PRO's CTF (Charge Trap Flash) technology is advertised like nearly interference-free, wrt to cell coupling and therefore improve longevity and retention performance (?)
https://downloadcenter.samsung.com/content/UM/2017...
mode_13h - Tuesday, January 4, 2022 - link
Thanks!back2future - Tuesday, January 4, 2022 - link
Considering 3d-Xpoint (Intel) there's 'fewer' information about data retention, but some (most) on cell performance (high IOPS for random r/w, write-in-place tech) and (r/)w endurance (TBW ~10x TLC-NAND types and P/E <=1billion-10million).If focus changes for newer gen4 SSD's Corsair MP600 gen4 compared to 3d-Xpoint Intel Optane 900p (PCIe 3.x), performance wise they are about on par.
https://www.techspot.com/review/1956-storage-perfo...
product examples
https://www.intel.com/content/www/us/en/products/s...
Solidigm, https://www.solidigmtechnology.com/en/products/dat...
P4800X "The Intel® Optane™ SSD DC P4800X follows the JESD218B-01 standard for data retention: 3 months of powered off retention at 40C. Powered on, data retention is throughout the product warranty period."
2010 table (so probably all SLC only), weeks for data retention
https://imgur.com/3r9yKxZ
( page 27, https://www.jedec.org/sites/default/files/Alvin_Co... )
active higher temperature on flash generally improves data retention (contrary to power-off retention time decrease)?
read disturbance comparison Xpoint, 3dNAND (if affected by technology)
page 14, https://dl.acm.org/doi/pdf/10.1145/3372783
2016/2017 review of Xpoint tech (& Micron QuantX)
"Current 2D NAND is already below a dozen electrons per cell, and even 3D NAND will encounter scaling limitations as lithographies shrink."
https://www.tomshardware.com/reviews/3d-xpoint-gui...
Infineon flash, data retention vs. temperature (figure 6) and P/E cycles (figure 10)
https://www.infineon.com/dgdl/Infineon-AN217979_En...
( L1 cache <=4TB/s on
https://cdn.ttgtmedia.com/rms/onlineimages/012221_... )
combined Xpoint and QLC raid approach
https://www.intel.com/content/dam/develop/external...
BTW, did read about '10 years retention time on 150°C' (PCM for enhanced data storage times, A. Redaelli, Ed., Phase Change Memory), what seem being a necessity (standard) for automotive devices/tasks.
data retention for 3DXP (3d-Xpoint) for client or enterprise flash storage devices ?
*Thanks to all*
mode_13h - Wednesday, January 5, 2022 - link
I have an old, NVME 1.0 Intel SSD that's probably MLC. Its datasheet said the same thing about a 3 month limit for power-off data retention, but I've left it powered off for probably close to 6 months at a time and lost nothing. I think that's just their minimum guarantee. I use BTRFS, which maintains per-block checksums that enable me to be fairly certain no (uncorrectable) bit-fade occurred.back2future - Wednesday, January 5, 2022 - link
researching was more about learning how flash cells technology improved and reality is better experience than theoretical limits, yesread endurance is some research work, but what to learn (common knowledge) for new consumer devices on QLC (2022) technology (different from professionals enterprise/datacenter storage devices and (data) maintenance knowledge)?
People (did) change from HDDs towards SSDs ...
Jaaap - Wednesday, December 15, 2021 - link
It has a 10-year retention time *at 150C* vs 100 seconds for normal NAND.Kamen Rider Blade - Wednesday, December 15, 2021 - link
When you archive data, who stores their physical media @ 150° C?Most people don't do that.
Eletriarnation - Wednesday, December 15, 2021 - link
This is true, but high endurance in extreme conditions can often imply extreme endurance in normal conditions. See also: the recent scandal about extreme-cold steel tests for US submarines.Kamen Rider Blade - Wednesday, December 15, 2021 - link
The person who faked the Metallurgy tests deserves the full force of the law thrown against them.ballsystemlord - Wednesday, December 15, 2021 - link
Spelling and grammar errors:"The company says that a standard modern memory cell with this level of control would only be able to retail the data for around 100 seconds,..."
"retain", not "retail":
"The company says that a standard modern memory cell with this level of control would only be able to retain the data for around 100 seconds,..."
Kamen Rider Blade - Wednesday, December 15, 2021 - link
The Write Endurance on these gotta suckWereweeb - Wednesday, December 15, 2021 - link
The question is: can it be adapted to 3D NAND processes?nandnandnand - Wednesday, December 15, 2021 - link
If it can't, there's absolutely no point in using it since you could use 3D + 1 bit per cell (SLC) instead.dwillmore - Wednesday, December 15, 2021 - link
As soon as I saw 7 BPC, I knew it wasn't going to be manufactured in any kind of advanced process. To be able to reliably store enough electrons to even be able to tell apart 128 different voltage levels, you'd physically need a large area--especially with the insulation thickness you'd need to get that 10y at 150C retention. Then they mentioned using it in microcontrollers and similar applications at 40nm and I was all "...and there it is."Might as well lump this in with FERAM and similar technologies that only make sense in very constrained applications.
BushLin - Sunday, December 19, 2021 - link
Isn't most NAND at 40nm, for endurance and it's become a race for how many layers can be stacked?mode_13h - Monday, December 20, 2021 - link
> Isn't most NAND at 40nmNoooo... not for a long time. There's been competition in both areal density *and* number of layers.
UpSpin - Friday, December 17, 2021 - link
I doubt the article is correct.Form 1-bit to 2-bit I need 100% more bits, and double the capacity at the same time, from 1 state I can store 2 states.
From 2-bit to 3-bit I only need 50% more bits, but still double the capacity, instead of 2 states I can store 4 states.
From 3-bit to 4-bit I only need 25% more bits, but again double the capacity, instead of 4 states I can store 8 states now.
....
So in case of 7-bit I can store 128 states (the reason I need to distinguish 128 voltage levels). So the point of the article is totally wrong. The more bits I add the cheaper it gets.
mode_13h - Saturday, December 18, 2021 - link
> From 2-bit to 3-bit I only need 50% more bits, but still double the capacity,> instead of 2 states I can store 4 states.
Doubling the number of states doesn't equate to doubling the storage capacity. I don't know what else to say, other than maybe try reading about information theory and some of it'll start to sink in?
> So the point of the article is totally wrong. The more bits I add the cheaper it gets.
I think that point isn't lost on anyone. The issue is that the incremental benefit of each further bit grows less and less. At some point, it's not worth the tradeoffs that come with packing more bits per cell.
mode_13h - Saturday, December 18, 2021 - link
As I was reading this, I got to wondering... does anyone know if conventional NAND does anything like storing a "full" cell per block, as a reference charge? When reading the block, you could use that to calibrate the ADC, essentially normalizing out the voltage drop due to charge leakage.bob27 - Saturday, December 18, 2021 - link
I'm not a physicist or electrical engineering person, but I assume voltage drift would occur statistically randomly. I.e. something that lets you determine in advance the average drift of a bunch of cells, but not the particular drift of a particular cell.back2future - Sunday, December 19, 2021 - link
please delete https://www.anandtech.com/comments/17116/startup-s...mode_13h - Monday, December 20, 2021 - link
LOL, yeah. That didn't work too well.Surprisingly, I managed to copy and paste it to a file, then base64 -d and get an *almost* valid JPG file. I'm just missing the X-axis label in your graph.
back2future - Tuesday, December 21, 2021 - link
possible also, inserting from data:image/jpeg;base64,/9j/4AAQSkZ...31KRFKUpE/9k= into browser address line (url for uniform resource identifier)( links without colons or bracket are functional also )
back2future - Sunday, January 2, 2022 - link
and knowing everything about YOU now :)('profiling' done, and interesting to know: https://app.rebrandly.com/public/links/share?href=... )
PaulHoule - Friday, December 31, 2021 - link
I am wondering if they are ever going to go to some number of levels which isn't a power of two. For instance you might be better off going from 16 levels to 25 levels instead of 32 levels, particularly if you are tuning dynamically for performance, persistence, device aging, etc.At the block level I don't see any problem being non-binary because you can arithmetic code your data. I know it is hard to parallelize but it doesn't seem too hard if you could lean on the main CPU instead of depending on inferior silicon in the device or put some small, specialized and fast-clocked chiplet into the device.
mode_13h - Friday, December 31, 2021 - link
> wondering if they are ever going to go to some number of levels which isn't a power of two.It might come to that, if 5-bit cells prove too challenging.
> At the block level I don't see any problem being non-binary
Yeah, I think that's not the main issue. As the article pointed out, the benefit of each additional bit per cell decreases exponentially, yet the tradeoffs are real. Once you start adding *fractions* of a bit per cell, the upside is even smaller. Maybe for like bottom-tier NAND, used in the lowest-margin products, it might still be worthwhile.
Another doubt I have is about the ADC technology you'd need to use. Naively, I think you'd need at least a 6-bit ADC to recover 4.5 bits of information per cell. However, maybe there's some way to build a non- base-2 ADC that would be more cost-effective.
Tomatotech - Saturday, January 1, 2022 - link
I’m guessing that the vast majority of data on SSD is actually static data that rarely changes from month to month (or even year to year).I wouldn’t mind an 8 TB m.2 drive where 4 or 6 TB is ultra cheap low cycle 7-bit storage, and 2-4 TB is faster / more durable SLC or MLC. Of course that requires more intelligent tiered storage monitoring brains on the m.2 drive but it seems feasible.
I don’t fully understand how it works but many modern nvme SSDs shift their storage between SLC / TLC / QLC as needed so if it’s possible to extend that further, I’d be happy with a nvme drive that shifted its storage space between 7+-bit long term storage and SLC as needed. Yes this means the capacity varies dynamically - this already happens behind the scenes with modern SSDs. Also over time some cells might become too degraded to be available for 7+-bit storage. They can just be redesigated as permanent SLC (or xLC) cells.
back2future - Sunday, January 2, 2022 - link
with customers getting information about wear leveling, TBW (with smart output) and long term storage capabilities of currently available flash cells within storage devices?Easy example: How does one get wear information on sdxc or sduc (<=128TB, ~GB/s) secure digital cards?