Computer data storage, often called storage or memory, refers to computer components and recording media that retain digital data. Data storage is a core function and fundamental component of computers.

In contemporary usage, 'memory' usually refers to semiconductor storage read-write random-access memory, typically DRAM (Dynamic-RAM). Memory can refer to other forms of fast but temporary storage. Storage refers to storage devices and their media not directly accessible by the CPU, (secondary or tertiary storage), typically hard disk drives, optical disc drives, and other devices slower than RAM but are non-volatile (retaining contents when powered down). Historically, memory has been called core, main memory, real storage or internal memory while storage devices have been referred to as secondary storage, external memory or auxiliary/peripheral storage.

The distinctions are fundamental to the architecture of computers. The distinctions also reflect an important and significant technical difference between memory and mass storage devices, which has been blurred by the historical usage of the term storage. Nevertheless, this article uses the traditional nomenclature.