  Penrose concluded that the demon needs to measure the location of the molecule, store that location in its memory, and can then extract the work. At the end of the operation, the demon retains the memory of where the molecule was located, maintaining the indeterministic outcome. He considered a demon repeating this process many times, gradually filling its memory up with the outcomes of previous measurements. If the demon's memory is finite, eventually it will run out of space, leading to one of two possibilities: either the demon ceases to be able to operate or the demon must reset some of its memory back to zero, which requires a corresponding increase in Boltzmann entropy elsewhere.