> Just out of interest, this is directly from page 9 of the datasheet for S=
T's
> 27C256B EPROM.
>
> "Research shows that constant exposure to room level fluorescent lighting
> could erase a typical M27C256B in about 3 years, while it would take
> approximately 1
> week to cause erasure when exposed to direct sunlight."

AFAIR we used to put 2716s in the sun for an afternoon on the
aforementioned brick window ledge.
But I think we tried to see how short you needed for OK erasure and
dim memory suggests that under an hour actually worked to tjhe stage
where you could program and verify them. That memory may be complete
rubbish. It was, after all, almost 30 years ago :-).

BUT the above was through glass and at an angle to the sun. NZ does
have a very high solar UV level, which helps.

 Russell
--=20
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