Secondary Memory 

This type of memory is also known as external memory or non-volatile. It is slower than main memory. These are used for storing data/Information permanently. CPU directly does not access these memories instead they are accessed via input-output routines. Contents of secondary memories are first transferred to main memory, and then CPU can access it. For example : disk, CD-ROM, DVD etc.

Characteristic of Secondary Memory

● These are magnetic and optical memories

● It is known as backup memory.

● It is non-volatile memory.

● Data is permanently stored even if power is switched off.

● It is used for storage of data in a computer.

● Computer may run without secondary memory.

● Slower than primary memories.