Physical Information Security remain separate entities by happenstance and by history. It typically involves physical controls such as protective barriers and locks, uninterruptible power supplies, and shredders. It primarily concerns the protection of tangible information-related assets such as computer systems and storage media against physical, real-world threats such as unauthorized physical access, theft, fire and flood. Security controls are intended to reduce the probability or frequency of occurrence and/or the severity of the impacts arising from incidents, thus protecting the value of the assets.