 Many basic concepts of information theory were developed in the nineteenth century in the context of the emerging science of thermodynamics. There is a reasonable understanding of the relationship between Kolmogorov Complexity and Shannon information (Li &amp; Vitányi 2008; Grünwald &amp; Vitányi 2008; Cover &amp; Thomas 2006), but the unification between the notion of entropy in thermodynamics and Shannon-Kolmogorov information is very incomplete apart from some very ad hoc insights (Harremoës &amp; Topsøe 2008; Bais &amp; Farmer 2008). Fredkin and Toffoli (1982) have proposed so-called billiard ball computers to study reversible systems in thermodynamics (Durand-Lose 2002) (see the entry on  information processing and thermodynamic entropy).  Possible theoretical models could with high probability be corroborated with feasible experiments (e.g., Joule’s adiabatic expansion, see Adriaans 2008). 