I’m curious about what is happening in the field of reversable computing. I haven’t heard much about it at all in the last 20 years. Basic information theory tells us that it takes energy to destroy information, so building ALUs that limit destroying information seems like a bit of a no brainer for attempting to create lower power (and heat) computing. The basic premise is that for any operation that loses info you store enough bits to allow the operation to run backwards. If you were clever about it, you could design your chips to only destroy bits in places that can be effectively as well. I’m sure reality gets in the way of pure theory, but I was sure that people were spending enough effort on the concept to have heard more about it.