A direct access storage device that is written and read by light. The most common types are CD, DVD and Blu-ray. As removable media, optical discs superseded the earlier magnetic disk cartridges ...

Examples include: Modern computer systems, such as mobile phones and MP3 players, all make use of solid state storage devices. These have no moving parts, which means they can: Be smaller ...

USB drives and optical discs are also storage. Memory is made up of "random ... They serve as both storage and RAM in remote sensors and similar devices but not as the main memory in computers ...