Re: NAND flash misery



cs_posting@xxxxxxxxxxx wrote:


Guess how many bad blocks are typical for NAND flash of several GB
capacity? As many as 2 percent! There could be the whole areas of
hundreds of megabytes of the contiguous bad cells, as well as the random
scatter.

I thought the IDE interface was supposed to hide that from the host by
mapping in spares?

It clearly does that, but only to a limited amount. Also, when a file gets broken because of the bad block, it is too late to replace it.

Isn't it also supposed to do wear leveling behind your back?

There is a whole lot of things that the internal controller could probably do; but we can only guess about what it actually does.


Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com
.

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