Hacker News Reader

Comment by amiga-workbench | Hacker News Reader

Surely it can't cost much more to go for a larger eMMC chip and have it massively over-provisioned with plenty of space for wear levelling?

The underlying flash memory is trash and the controller already does a ton of heavy lifting to keep the data coherent.

View on HN

But then you are not only making your build price higher, you also have less revenue as year pass. And its hard to market.

It's a $1,700 bottom barrel android tablet, there is plenty of profit margin available.

I don't think the problem is necessarily space, but rather write-limits being used by superfluous logging

If I remember correctly it's also about eMMC having a much shorter life than UFS or similar storage. Though yes, unnecessary logging isn't helpful either. (Quick post-googling edit: apparently both use NAND, it's more about wear leveling apparently that makes the differences.)

That's where the wear levelling comes in, still expose 8GB of space to the host device, but internally have I dunno, twice that in cell capacity that you can move bits to as other cells wear out.

Its a shame mobile devices don't have a SMART equivalent, would be nice to have some warning as something approaches the end of its life.

Do you even have to limit the exposed space?

It’s not going to write at twice the rate just because more space is available.

You do, most SSD controllers already implement this. Have you ever wondered why most SSD's come in slightly odd sizes like 100GB instead of 128GB? The extra space is put aside and used for wear levelling and other maintenance tasks.

You can find out a bit more here https://www.seagate.com/gb/en/blog/ssd-over-provisioning-and...

I also remember a guide a while ago on how to reprogram a SSD to operate in SLC mode instead of MLC. You lost disk capacity but gained a large performance boost and a reduced error rate.

Why do you want to spend money on hardware to solve a software problem? The software doesn't have to write the logs to the SD card.

Reply on news.ycombinator.com