Describe the idea about cache memory and its limitations and benefits

Describe the idea about cache memory and its limitations and benefits

When a program is running on the computer it is in random access memory or RAM. RAM is a bigger but slower memory (faster than optical devices). Cache is a smaller and faster memory and on a level nearer to processor than the RAM. In CPU’s fetch-decode-execute cycle, whenever a fetch is done, either for a memory or data, CPU first goes to cache memory. Cache memory contains the copies of data from the most frequently visited main memory locations (because when a memory is used again and again during the execution of a program, it is more likely that this memory location contains data that will be used often).  There are three types of cache one contains the copied of data from frequently used memory locations, second one contains executable instructions to be fetched and third one (called TLB or translation lookaside buffer) maintains a lookup table to map virtual memory (as seen by program) to physical memory address.

Particular areas of cache memory are its locations. On-chip cache and on-board cache etc. Its main power is that the memory management is easy and fast when you have often “cache hits” (cache hit and cache miss are terms used for when a required data is present in cache and when its not in cache respectively). Limitation is obviously that it is small in size (capacity).