Cache Memory and Register
Cache Memory is a special high speed main memory used to increase the processing speed by making program and data available to CPU at high speed.
Cache memory stores the portion of the program that is currently being executed in the CPU and temporary data frequently needed in current computation. Thus it acts as buffer between CPU and main memory.
Cache memory is a high speed main memory (SRAM).
The performance of cache memory is measured in terms of hit ratio.
Hit ratio = number of hits/total CPU reference to memory
= number of hits/[number of hits + number of misses]
Why cache memory is required?
The speed of the CPU is generally faster than main memory's speed. This results in slow down in processing speed of the CPU as main memory is not able to provide data and instruction as per CPU's processing rate. So a technique was developed of using a small, high speed cache memory and place it in between CPU and main memory.
Cache memory access time is almost close to CPU cycle time. Thus cache memory helps in increasing the performance of the computer.
Cache memory stores the portion of programs currently getting executed in CPU and any temporary data needed for computation.
It acts as a buffer between CPU and main memory.
Registers refers to internal memory used inside the CPU.
They have speed that matches with that with CPU thus are able to provide data and instructions at rapid rate for processing.
Registers holds temporary results while computation is in progress.
Registers are very expensive.