[sdiy] New project idea: probability trakker !?

[Cornutt, David K]

From: Roman [mailto:modular at go2.pl]
> what's wrong with Microchip serial EEPROMs?
> say 128kbits 1000000 rewrite cycles, data retention 200 years
> or at least they say so. With 1000000 cycles it's hard to break
> the chip. Say, 1 write per 20s, 8 hours a day, that gives 2 full
> years of constant manipulation with no time to play the thing.

I think they are talking mainly about old stuff.  I do recall that with
early EPROM designs the manufacturers were very specific about
making sure that you covered up the window after programming,
else stray light could erase them after a period of time.  If that
were true, then it also stands to reason that they would be
erased over time by higher-energy radiation like cosmic rays
and natural gamma radiation.  

And, some of the '80s EEPROM designs were only good for a
few thousand write cycles.  They also had problems with 
degredation when exposed to ambient temps over 100F
(40C), which is not uncommon to find inside some electronics
boxes.