It is widely believed that measurement is accompanied by irreversible entropy increase. This conventional wisdom is based in part on Szilard\u27s 1929 study of entropy decrease in a thermodynamic system by intelligent intervention (i.e., a Maxwell\u27s demon) and Brillouin\u27s association of entropy with information. Bennett subsequently argued that information acquisition is not necessarily irreversible, but information erasure must be dissipative (Landauer\u27s principle). Inspired by the ensuing debate, we revisit the membrane model introduced by Szilard and find that it can illustrate and clarify (1) reversible measurement, (2) information storage, (3) decoupling of the memory from the system being measured, and (4) entropy increase associated with memory erasure and resetting
