In computing, external storage is referred to as backing storage. It is a type of secondary storage that is used to store data and programs outside of the computer's main memory or internal storage. This can include devices such as hard drives, solid-state drives (SSDs), and USB flash drives. Backing storage is called "external" because it is not part of the computer's internal components and is instead connected to the computer through an external interface such as USB or FireWire. The term "backing" refers to the fact that the storage is used to back up data, and can also be used to store large amounts of data that cannot fit in the computer's main memory.