On Wed, 2012-04-04 at 06:54 -0400, Atlant Schmidt wrote: > Matej: > > > Artem, you said that this unstable bits only happen > > during power cuts, is this right? Would those appear > > also on simulated power cuts, the ones that integck > > can produce? > > (Note: This isn't Artem replying.) > > Unstable bits can happen anytime, but *REAL* power-cuts > while writing are certainly a great way to produce them; > after all, if you've only transferred half the electrons > to the floating gate when power goes away, well, that > Flash cell is now a roll-of-the-quantum-dice each time > you read it. > > Simulated power cuts (that just stop the software > processing at arbitrary and random points) can't > produce this effect. > > But any time a read-disturb or write-disturb takes place, > there's some probability that a Flash cell will be left > with a "near-threshold" charge on the floating gate, so > unstable bits are a fact of life that must be faced by > any software that drives NAND Flash memory chips. This > is, of course, especially true of MLC chips and even > more-true for TLC chips (with three bits per cell). Yeah, thanks for correcting. Yeah, read/write-disturb may make bits to become unstable, but we assume this is a slow process which will gradually make more and more bits flip and ECC will take care of that. So I think Matej can exclude this. -- Best Regards, Artem Bityutskiy