Cache Memory

Cache memory (pronounced as “cash”) is placed between CPU and main memory. It is a semi-conductor memory consisting of static RAMs. It is a special and very high speed memory called a cache used to increase the speed of processing by making current program and data available to the CPU at a rapid rate.

It stores instruction, codes, and data, which are to be currently executed by the CPU. It is used to reduce the average access time for instruction and data, which are normally stored in the main memory. A cache memory also needs a cache controller for which cache controller ICs are available.

The technique of accessing a cache memory differs from that of main memory. It work according to ‘hit and miss’ on the matching of addresses from main memory to CPU and to it.

Cache memory is placed at two-three levels: first, second, and third level as L1, L2 and L3. Some microprocessor contains L1 and L2 and some contains L1, L2 and L3 within the microprocessor. Cache within the microprocessor is internal cache and outside the processor is external cache. So we can say cache memory in computer system is to compensate the speed difference between the main memory access time and processor logic. The use of cache memory lets the processor work in its actual speed.