Difference between primary and secondary memory?

Main memory is also called primary memory.Main memory is on the semi-conductor chips.These chips are connected with the CPU on the motherboard.Main memory is very fast and it is directly accessible by the CPU.Different types of memory chips are RAM,ROM,PROM,etc.

Secondary memory is also called Backing Storage memory.It is used to enhance the capacity and performance of main memory.Examples of secondary storage are Floppy disks,Magnetic disks,Magnetic tapes,CDs,Hard disks can store a bulk amount of data.