Reversible computer designs people actually consider building do a small bit of irreversible computation copying end results of the reversible computations into irreversible memory before rolling back the reversible computation. Perfectly reversible computations are a bit useless since they erase their results when they start rolling backwards.
Reversible computer designs people actually consider building do a small bit of irreversible computation copying end results of the reversible computations into irreversible memory before rolling back the reversible computation. Perfectly reversible computations are a bit useless since they erase their results when they start rolling backwards.
You can erase some of their results without erasing others, of course.
Nobody says you have to run a reversible computer backwards.
A big part of the point is to digitise heat sinks and power management. For details about that, see here.