Computer Architecture Questions
Cache memory is a small, high-speed memory component located between the CPU and main memory in a computer system. Its purpose is to store frequently accessed data and instructions, allowing the CPU to quickly retrieve them without having to access the slower main memory.
Cache memory works on the principle of locality, which states that programs tend to access data and instructions that are close to each other in time and space. When the CPU needs to access data or instructions, it first checks the cache memory. If the required data is found in the cache (cache hit), it is retrieved quickly. However, if the data is not present in the cache (cache miss), the CPU has to access the main memory to retrieve it, which takes more time.
Cache memory operates using a hierarchy of levels, typically referred to as L1, L2, and L3 caches. L1 cache is the smallest and fastest, located closest to the CPU. It stores the most frequently accessed data and instructions. L2 cache is larger but slower, and L3 cache, if present, is even larger but slower than L2 cache.
Cache memory utilizes a cache replacement policy to determine which data to keep in the cache when it becomes full. The most commonly used policy is the least recently used (LRU), which removes the least recently accessed data from the cache when new data needs to be stored.
Overall, cache memory plays a crucial role in improving the performance of a computer system by reducing the time taken to access frequently used data and instructions, bridging the speed gap between the CPU and main memory.