Primary storage device

Alternatively referred to as internal memory, main memory, and primary memory, primary storage is a storage location that holds memory for short periods of times while the computer running. For example, computer RAM and cache are both examples of a primary storage device. This storage is the fastest memory in your computer and is used to store data while it's being used. For example, when you open a program data is moved from the secondary storage into the primary storage.

Secondary storage

Also see: Memory terms, Off-line storage, Secondary storage device, Storage device