Reversible Architectures

Abstract

Reversibility is put into practice in accordance with the basic principles described in the previous chapter. Several architectures are proposed to convert the conventional non-reversible logic operators into reversible operators. We also design an architecture for a reversible full adder, a physical device that does something. We then generalize these ideas in order to define a general-purpose reversible computer. Our first attempt works perfectly, but generates a great deal of garbage information (disorder), so we design a second architecture that does not generate disorder, and explore it in some depth. We conclude with some comments concerning the energy used in reversible computations and briefly mention reversibility in relation to quantum computing. In this sense, reversibility acts as a bridge between conventional computing and quantum computing.

As we live and as we are, Simplicity—with a capital S—is difficult to comprehend nowadays. We are no longer truly simple. We no longer live in simple terms or places. Life is a more complex struggle now. It is now valiant to be simple: a courageous thing to even want to be simple. It is a spiritual thing to comprehend what simplicity means.

Frank Lloyd Wright