Storage Devices A storage device is a hardware device capable of storing information. A storage device is a hardware device capable of storing information. There are two storage devices used in computers; a primary storage device such as computer RAM and a secondary storage device such as a computer hard disk drive. Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is one of the core functions and fundamental components of computers. Primary storage Primary storage (or main memory or internal memory), often referred to simply as memory, is the only one directly accessible to the CPU. The CPU continuously reads instructions stored there and executes them as required. Any data actively operated on is also stored there in uniform manner.