Random access memory (usually known RAM) is a type of computer data storage. It takes the form of integrated circuits that allow the stored data to be accessed in any order, i.e. at random. This contrasts with storage mechanisms such as tapes, magnetic discs and optical discs, which rely on the physical movement of the recording medium or a reading head. In these devices, the movement takes longer than the data transfer, and the retrieval time varies depending on the physical location of the next item.