A storage device in which the ability to access a randomly selected bit of stored data is independent of either the timing of the most recent access of that bit or the location of the most recently addressed bit. Data may be read nondestructively, but existing data is automatically erased when new data is written into a specific bit location. RAMs may be either static (that is, able to retain data when the power supplies are not biased) or dynamic (that is unable to retain data unless a "refresh" voltage is periodically applied).