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It is a physical quality of flash memory that each flash cell has only a limited number of writes it can handle before it fails. If you want to know the dirty d

by hristov 15y ago

It is a physical quality of flash memory that each flash cell has only a limited number of writes it can handle before it fails. If you want to know the dirty details, what happens is that electrons eventually get trapped in the dielectric of a flash cell and ruin everything. This cannot be fixed unless someone invents a new electron capture proof dielectric. Flash memories use all kinds of electronics to ameliorate this problem, but in the end most they can do is try to equalize the number of writes each cell experiences, which results in the drive working at close to its full capacity for as long as possible but then failing very quickly afterwards.

copper 15y ago
Mind you, there have been people working on clearing up trapped charges. I doubt there's been much usable progress (IIRC, the methods involve some kind of irradiation of the dielectric, which is difficult to perform in situ.)
Symmetry 15y ago
If this was the failure mode experienced by most drives that fail, though, it wouldn't happen for years and even after you were no longer able to write to the drive you would still be able to read from it. This might be how the more reliable Intel or Samsung drives end up failing, but all evidence is that the failure modes of the highest performance but less reliable drives seem to be more interesting than that.
- hristov 15y ago
  Why do you think it would not happen for years? As I mentioned in a previous post there is a trade off between price memory size and failure rate so some of the higher density memories will have much lower life than what you may be used to. And no you would not be able to read from it. When a flash cell wears off the ability to read it degrades or disappears. Depending on the memory you still may be able to recover the data using ECC or the like, but this ability tends to disappear as large numbers of cells start dying.

by hristov 15y ago

copper 15y ago

Mind you, there have been people working on clearing up trapped charges. I doubt there's been much usable progress (IIRC, the methods involve some kind of irradiation of the dielectric, which is difficult to perform in situ.)

Symmetry 15y ago

If this was the failure mode experienced by most drives that fail, though, it wouldn't happen for years and even after you were no longer able to write to the drive you would still be able to read from it. This might be how the more reliable Intel or Samsung drives end up failing, but all evidence is that the failure modes of the highest performance but less reliable drives seem to be more interesting than that.

hristov 15y ago
Why do you think it would not happen for years? As I mentioned in a previous post there is a trade off between price memory size and failure rate so some of the higher density memories will have much lower life than what you may be used to. And no you would not be able to read from it. When a flash cell wears off the ability to read it degrades or disappears. Depending on the memory you still may be able to recover the data using ECC or the like, but this ability tends to disappear as large numbers of cells start dying.