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posted by martyb on Saturday July 01 2017, @02:04AM   Printer-friendly
from the quite-a-bit-better dept.

Western Digital has announced that it will begin production of 96-layer 3D NAND in 2018. It will make triple-level cell and quad-level cell NAND with die capacities ranging from 256 Gb to 1 Tb. QLC NAND is predicted to have 100-150 program/erase cycles (endurance) compared to about 1000 for TLC:

Given such endurance, it is logical to expect 3D QLC NAND to be used for primarily removable storage as well as for ultra-high capacity datacenter drives for the so-called near-WORM (write once read many) storage applications. For example, Toshiba last year discussed a QLC-based datacenter SSD with 100 TB capacity for WORM apps.

Western Digital plans to begin sampling of select 96-layer BiCS4 3D NAND configurations in the second half of this year, but the manufacturer does not specify which dies will sample when. As for mass production, Western Digital intends to start volume manufacturing of their 96-layer 256 Gb 3D NAND in 2018, with other dies to follow later. Based on Western Digital's announcements made earlier, the company will gradually introduce more sophisticated BiCS4 96-layer configurations in 2018 and 2019, before moving to BiCS5 sometimes in 2020. That said, it makes sense to expect the highest capacity BiCS4 ICs to ship later rather than sooner.

[BiCS = "Bit-Cost Scaling". Yes, it does not make sense to me, either. --Ed.]


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  • (Score: 2) by qzm on Saturday July 01 2017, @11:27AM

    by qzm (3260) on Saturday July 01 2017, @11:27AM (#533879)

    'Given such endurance, it is logical to expect 3D QLC NAND to be used for primarily removable storage'

    Except that the unpowered data retention, with such small write endurances, is likely to be TERRIBLE.

    WORM applications may well be ok - as the controller continuously scans the cells and refreshes ones drifting (thank you, advanced ecc..)
    However, removable storage, with the implication of long term unpowered data retention? I suspect not.

    QLC, without a major improvement in cell stability, is going to be a long term reliability disaster.
    I can see poor low-end consumers wearing the fallout from that one - cheap SSD drives in OEM equipment that are unreliable but 'meet industry
    standards'.

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