The parts of the computer that are used to store data in whatever form are classified as storage devices. Computer storage is either primary or secondary and is either volatile or nonvolatile.

Primary memory is commonly used to mean random access memory (RAM) but actually refers to all memory that work in tandem with the processor. The central processing unit (CPU) or accelerated processing unit (APU) read instructions stored in primary memory and execute the instructions as required.

Secondary memory is secondary because data stored within secondary storage media (usually disks) cannot directly communicate with the microprocessor. Data stored in such media first is transferred to main memory (DRAM) from where manipulation by the processor can occur.

• Primary storage

• DRAM
• SRAM
• ROM

• Secondary storage

Internal storage & External storage

• Magnetic storage
• Optical storage
• Flash storage
• Paper storage

• Computer Memory Devices in Detail
  Computer memory can grouped as primary and secondary: While primary memory can be volatile and nonvolatile i.e. DRAM and ROM, secondary memory is nonvolatile and capable of storing data permanently.

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