Reversible computing is good news for power consumption and heat dissipation (including in the long term) - but not great news - bacause of the reasons I go over in my article.
If you think that actually running things backwards is actually an attractive answer, perhaps think some more about how you are going to correct all errors and prevent an error catastrophe upon reversal - and about how you are going to propagate the "reverse now" signal in a reversible manner.
perhaps think some more about how you are going to correct all errors and prevent an error catastrophe upon reversal
The normal way. This generates waste heat, but at a rate which depends on the error rate of your components. Under our current understanding of physics, this can be driven essentially to zero in the long run. Even if it can't, it can at least be driven down until we encounter some as-yet-unknown fundamental physical limitation. If we imagine people living in a reversible CA, or any other laws of physics which we can understand, then we can...
This post may be interesting to some LWers.
In summary: it looks like our universe can support reversible computers which don't create entropy. Reversible computers can simulate irreversible computers, with pretty mild time and space blowup. So if moral value comes from computation, negentropy probably won't be such an important resource for distant future folks, and if the universe lasts a long time we may be able to simulate astronomically long-lived civilizations (easily 10^(10^25) clock cycles, using current estimates and neglecting other obstructions).
Has this been discussed before, and/or is there some reason that it doesn't work or isn't relevant? I suspect that this consideration won't matter in the long run, but it is at least interesting and seems to significantly deflate (long-run) concerns about entropy.