  We show that any external intervention (insertion or removal of a partition)
that destroys the equilibrium or brings it in a system always requires work and
heat to ensure that the first law is obeyed, a fact that has been completely
overlooked in the literature. As a consequence, there is no second law
violation. We discuss the ramifications of our finding for information
principles of Szilard and Landauer and show that no information entropy is
needed. The relevance of this result for Maxwell's demon is also considered.
