Eric L. said:
Before I get into the nitty-gritty of the problem, I would like to know the
consensus on whether Flash Memory can be corrupted by anything other than
cosmic rays, nuclear detonation, and the occasional ray gun. All kidding
aside, does anyone have any information on EMI, and/or RFI causing bits to
flip?
Best regards,
elarson
I bet if you put a Flash Memory chip in liquid helium some of the bits would
drop out, and maybe
-20 F.. I don't know, but it could happen if it gets cold or hot enough.
I think you can exclude EMI wavelengths longer than 4 times the longest edge
of
the device from considiration as having no effect whatsoever.
That means radio waves below microwaves would have to be extremely powerful
to effect the device. Put the chip in a microwave, turn it on, then
test.... and if my guess is right, there will be problems. I think it
would probably turn out that you have to hit the chip-level electronics with
ultraviolet light to have any hope of flipping bits.. and gamma radiation
would be more effective.
If the memory is inside a metal case, it would be better off for
reliability.
If I were on a jury however, I would conclude that bit-flipping is too
far-fetched a defense.
the wavelength of the offending EMI has to be shorter than four times the
length of the structure it interacts with, to interact with it
substantially.. furthermore it has to result in enough 'kick', the rush of
phonons from the strike spot to
cause enough electron excitation to bump the voltage enough to cause
the bit to change and still the circuit has to be susceptible to register
this change.. so its an
unlikely proposition even if you try... but if you try a few billion times
as in a radioactive minute you might have some luck.
RFI is EMI limited to the RF bands.
If you record 1,000,000 flash memories then drop them all, one at a time, 3
feet onto the pavement, 50 of them will have permanent errors from breakage.
If you record 1,000,000 flash memories then read them back, one or two will
have non-repeatable errors... thats just the way it goes (without recourse
to voodoo or microsoft).
If that's true it's a one in a million chance for just bad luck with 'bit
retention'.
Another thing is ageing. Since the 'decay' of chemistry within the chip is
a function of time..it would stand to reason that with every passing second
flash memory is more vulnerable to failure.
After 100 years there is a slim chance that much data could still be
intact. 0 will still be zero, but adjusting for
inflation, 1 will be around 27 (which screws up binary), and gasoline will
be $421 per milliliter
(synthetic) - converted from yen since the dollar won't exist, having since
surpassed
itself by it's value as heating fuel and toilet paper.
hope that helps
elvis