Learn: Cache

Welcome!Welcome to today's lesson! We'll be exploring cache, a key concept in computer science. Let's dive in and learn how it helps improve the performance of computers.

What is Cache?A cache is a small, fast type of memory located close to the CPU. It temporarily stores frequently accessed data to reduce the time it takes for the CPU to access this data. This makes processing faster and improves overall system performance.

Why is Cache Important?The CPU is the brain of the computer, but accessing data directly from RAM can be slower. Cache bridges the gap by storing copies of data the CPU is likely to use again. This helps reduce delays and increases the speed of operations.

Levels of CacheCache is organised into levels: L1, L2, and L3. L1 is the smallest and fastest, located inside the CPU. L2 is slightly larger but slower. L3 is larger still and shared across cores, but it's the slowest of the three.

How Cache WorksWhen the CPU needs data, it first checks the cache. If the data is found, this is called a cache hit, which is faster than fetching the data from RAM. If the data isn't in the cache, a cache miss occurs, and the CPU has to fetch the data from slower memory.

Cache Replacement PoliciesWhen the cache is full, older or less frequently used data is replaced to make room for new data. This is managed using cache replacement policies, such as Least Recently Used (LRU), which replaces the least recently accessed data.

Review Time!Great work! You've learned about cache memory, its levels, how it works, and replacement policies. Now let's test your understanding with a few questions.