Why Do Computers Have 3 Types of Memory? | Programming Fundamentals #1

We know that memory is used to store data and there are 3 types of memory we use in daily life:

1)Cache memory:- which is used to store frequently used data and it is present close to the CPU.

2)Main Memory:- All programs are loaded and stored here during execution and it is also called volatile/temporary memory(because everything is lost when the system shuts down).

3)Secondary Memory:- It is used to store permanent information and data. Here we have 2 categories-first is Internal storage(SSD, HardDisk) and second is External storage(PenDrive, SDcard, etc).

But the main question is: why do we have 3 types of memory?

For an ideal memory they should obey 3 below desirable features:-

 a)Memory should have low access time.
 b)Cost of memory should be low.
 c)Capacity to store data should be High.

However, None of these 3 types of memory have all these features:-

1)Cache Memory:-
   -Low access time
   -High Cost
   -Low Capacity

2)Main Memory:-
   -This memory is moderate in all these three features.

3)Secondary Memory:-
   -High access time
   -Low Cost
   -High Capacity