EPROMs only keep memory 20 years!

It seems the data retention time for an EPROM memory is only 20 years.... http://www.st.com/stonline/products/families/memories/eprom/epromfaq.htm
And when these EPROMS fail, they will "bit flip" (changing a 0 to a 1 or a 1 to a 0)... http://trs-new.jpl.nasa.gov/dspace/bitstream/2014/41262/1/09-9.pdf
So what about all those vehicles on the road manufactured in the 80's with EPROMS in the engine computers?
What else is still out there?
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Only 50 erasing/programming cycles? Probably all '80s cars will be scrapped before their EPROMs fail, there are hardly any left in Iraklion (180,000 residents). 20 years is an estimate, not a death sentence.
--
Tzortzakakis Dimitris
major in electrical engineering
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I know that in the 80s "we" designed some spacecraft computers that, in flight, were expected to use "fuse link" type proms. The horror story about they was that the fuse link could "grow back." I've been out of the business since 1985 or so; I have no idea how these problems were resolved.
The Hubble Space Telescope likely had some of those PROMs.
EPROMs were erased with UV light. One can only assume that radiation (especially gamma and xray) would "clear" them.
I didn't check you link but I don't understand "bit flip." I understand how the burried charge would dissipate and some cells go back to the original, un-programmed, state (whether 1 or 0) but turning some 1's to 0's and some 0's to 1's in the same chip goes beyond the physics of the devices as I understand it.

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