SIGNAL ENTROPY AND THE THERMODYNAMICS OF COMPUTATION

Electronic computers currently have many orders of magnitude more ther modynamic degrees of freedom than information-bearing ones (bits). Bec ause of this, these levels of description are usually considered separ ately as hardware and software, but as devices approach fundamental ph ysical limits these will become comparable and must be understood toge ther. Using some simple test problems, I explore the connection betwee n the information in a computation and the thermodynamic properties of a system that can implement it, and outline the features of a unified theory of the degrees of freedom in a computer.