Kioxia Talks 7-bit per cell NAND
Yeah, TLC 3-bits per cell, PLC at 4-bits, but Kioxia is thinking ahead, at7-bits per cell, to really boost volume sotage for NAND SSDS.
Kioxia, a prominent vendor, demonstrated how multi-value storage technology improved the number of bits that can be held in one memory cell . Kioxia has created an ultra-multi-valued storage technique capable of storing up to 7 bits of data in a single 3D NAND flash cell. During last year's International Memory Workshop, the business presented a multi-valued storage solution that can store up to 6 bits in a single 3D NAND flash cell (IMW 2021). The discoveries reported this time are the result of further advancements in this research.
Similar to the 6bit/cell technology revealed the previous year, the ambient temperature was not room temperature but 77K, which is an environment of exceptionally low temperature. This is done to decrease data read noise. In addition, the material of the channel was changed to epitaxially grown single-crystal silicon. The electrical resistance is lower than that of routinely utilized polycrystalline silicon. The cell transistor's subthreshold properties have been enhanced, and the leakage current has been diminished. In the prototype cell, it was confirmed that these techniques decreased the threshold voltage variance during the write and read operations, allowing the threshold voltage to be written and read in 128 steps equivalent to 7 bits.
While even bigger SSDs likely are be pricey, an overly sophisticated controller could render ultra-high-capacity drives prohibitively expensive and nullify their benefits. Western Digital predicts that even after 2025, PLC 3D NAND (5 bpc) will have little use. Kioxia now proves the physical possibility of storing seven bits per cell and even discusses the eventual storage of eight bits per cell.
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I imagine an endurance of 10 cycles if we are lucky with that 7bits
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If it is possible to do it, then they should do it.
Every improvement is a step ahead.
The price is right for 4TB TLC (if mainstream), but it is lot less for 4TB in QLC: it is around 350 in 2,5" and 450 in M2.
At 800 you can have a 8TB from Samsung in QLC (with good life due to it's high volume Nand).
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There is still a business with magnetic tape anyway

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Agreed - so long as SLC, TLC, and QLC are still in production, I don't mind going up to 7 bits if it means mass storage for cheap. Not everyone needs a lot of performance, they just need a lot of cheap capacity with high reliability.
SLC will remain good for those who need top performance.
QLC is good for budget drives that suit most PCs.
TLC is a nice in-between.
7-bit will be ideal for archiving and NASes.
Is SLC still even made or put in large quantities on SSDs? It was prohibitive expensive.
MLC was my first SSD in 2013/14: at 256Gb it was the same price as a 2Tb HDD but the performance was there and I was happy for years.
Came 2019 I upgraded to my current 512Gb M.2 I think it's TLC, I notice the life dropping a bit faster (I'm at 89% health now) but I'm using it allot harder than my old SSD and that still lives on my mom PC.
QLC is a bit scary to be honest, but if the price comes down and density comes up I can't really complain. I think we're getting into diminishing returns territory pushing QLC forward, time will tell if they can improve reliability.
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I imagine they're going after the magnetic tape business with this