Jeff Oshima of Toshiba gave a keynote at the Non-Volatile Memory Workshop this week at the University of California at San Diego. Toshiba invented flash storage in 1987, so I'm always interested in what they have to say about their pride and joy.
This was part of Mr. Oshima's overview of Toshiba's continuing investment in flash technology. Bit Column Stackable (BiCS) 3D flash. Through Silicon Vias (TSV). High speed flash interfaces. And, of course, Quad level cells.
QLC enables a single cell to hold 4 bits of data. That increases storage density by a third, without the extra costs involved with 3D manufacturing. Cheaper flash, for almost free.
But there are downsides. With each increase in bit density - from SLC to MLC to TLC - the cell becomes more sensitive to wear and provides fewer writes before it can be written no more.
In the case of QLC, Mr. Oshima suggested the limit would be about 500 writes, which, surprisingly, the Google SSD study found isn't much less than what SSDs in heavy use see.
Translation: should be fine for consumer and, with proper controller firmware, enterprise use.
What's more, Mr. Oshima predicted that Toshiba would be able to offer 2.5" 88TB flash drives that combined QLC, BiCS, and much higher z-axis chips. That's a few years out, but definitely on the Toshiba roadmap.
The Storage Bits take
There's little chance that disk drives will catch up with flash, and the pace of flash innovation raises the bar for all the NVM comers, such as 3D Xpoint and Crossbar.
I plan to cover some of the other of Toshiba's advances in a later post. But the bottom line is that flash will continue to improve in density and cost, as well as performance.
Comments welcome, as always. How about a tablet with a 4TB flash drive?