What is RAM?

Question

I have few questions about Cache Memory

1) My understanding of cache memory is, there are 3 type of cache memory,
1. Within RAM
2. Within CPU (L1,L2,L3)
3. Separate Hardware which is costlier than all others.

Please correct if I am wrong,

2) Who stores the data into cache? I mean, can we write a program which should use only cache memory? If yes then how to do it? if no then who manages that?
For example,
Cache memory within RAM, is it managed by Kernel?(Memory Management Unit)
Cache memory within CPU, is it managed by CPU itself?

3) Why cache memory is faster than RAM?

Answer 1

RAM i.e. Random access memory is a type of data storage used in computers that is generally located on the motherboard. This type of memory is volatile and all information that was stored in RAM is lost when the computer is turned off. The RAM chip may be individually mounted on the motherboard or in sets of several chips on a small board connected to the motherboard.

Types of RAM
Dynamic random access memory (DRAM) and
Static random access memory (SRAM).

SRAM is volatile memory and is often used in cache memory and registers because it is a lot faster and does not require refreshing like Dynamic RAM. SRAM retains information and is able to operate at higher speeds than DRAM.
Dynamic RAM is memory that needs refreshing. The refreshing is done by the memory controller which is part of the chipset on the motherboard.