It sounds unlikely: technology that makes MLC flash as reliable and long-lived as more expensive SLC? Right!
Or even better: make 3 bit per cell flash equivalent to 2 bit MLC? What are these guys smoking?
Whatever it is, I’d like to try some myself. Because it looks like they have the goods.
Flash vendors are close-mouthed about flash problems, not wanting to kill the goose that’s laying billion$ in revenue. But the problem most people worry about – life span – isn’t much of a problem.
So what is? Errors. The good news: most NAND flash errors have predictable causes. And what can be predicted can be corrected.
That’s Avraham Meir’s story and he’s the CTO of Anobit. We had a chat at SNW.
According to their web site:
Mr. Avraham Meir is an internationally recognized authority in NAND Flash technology and products. Prior to joining Anobit, Mr. Meir was VP Corporate Engineering at SanDisk (NASDAQ: SNDK), and the CTO at M-Systems (NASDAQ: FLSH, acquired by SanDisk).
Flash errors are commonly due to cross coupling between adjacent cells, read disturbs and program disturbs, and reading or programing the wrong cell. Retention impairments and endurance impairments are more common as geometries shrink.
Data retention phenomena and endurance effects are not random: normally high levels go to lower levels. In adjacent cells, one high and the other low, voltage will leak across to reduce the higher voltage.
So the first stage is reducing errors is knowing how flash impairments behave to predict an error. Then working with flash vendors they can repair the impairment in the wild.
By reducing the errors first and then applying signal processing and error correction Anobit makes less-reliabile flash look like more reliable flash.
Extending endurance has another effect: with flash as the number of writes increases so does the error rate. And as the endurance increases the data retention time drops to as little as a few months. Write once and your data may last for years. But don’t trust that old thumb drive.
The StorageMojo take
Anobit has an impressive IP portfolio: go to the USPTO patent application search engine, type in anobit and you’ll see what I mean. And they have about a dozen granted already.
What is evident is that flash as a medium is still in its infancy. If it turns out, as some predict, that flash will hit a geometry wall in a generation or two, Anobit’s technology looks to be transferrable to whatever next-gen non-volatile device wins. In storage, reliability and endurance are problems that will never go away.
Courteous comments welcome, of course.