Each of us, from our own experience, knows that computers emit a lot of heat while working. Even small server rooms require the use of air conditioning. So, computers uses a lot of energy. We shall study this phenomena more precisely in one of the next lecture. However until now we do not know precise lower bouds for the energy costs of computations. We do not know whether the calculations require any energy!!!

We will now discuss two issues related to this topic:

1. Landauer' principle
2. Current technology trends (Moore’s law for computing efficiency)
3. Reversible computing