What is primary storage?

• A. Non-volatile external storage where OS and applications are stored when not in use like HDD, SSD, CDs and SD cards.
• B. External cloud storage.
• C. Non-volatile memory used for long-term backups.
• D. Mostly volatile memory areas that the CPU can access quickly like registers, RAM and cache.

Answer: (D)

Primary storage is the fast, directly usable memory the CPU uses while executing programs. It is typically volatile, meaning it loses data when power is removed. This category includes the CPU’s registers, the caches (L1/L2/L3), and RAM. These memory types are designed for very low latency access to the instructions and data the processor is actively working with. In contrast, non-volatile storage like HDDs, SSDs, optical disks, external cloud storage, or tape is used for long-term persistence and backup, not for the immediate, high-speed work of the CPU. So the correct idea is that primary storage consists of volatile, quickly accessible memory areas such as registers, RAM, and cache.