Cache
Fast temporary storage between CPU and main memory, reducing average access latency through locality exploitation. Caches store frequently used data and instructions. Multilevel caches (L1, L2, L3) provide tiered speed/size tradeoffs.
Formula
Hit Rate = Cache Hits ÷ Total Accesses × 100%
Real World
When you scroll through your TikTok feed, the app pre-loads upcoming videos into a local cache so they play instantly — a cache miss would cause buffering while data fetches from a remote server.
Exam Focus
Distinguish cache hit from cache miss and explain the performance consequence of each — marks require both definition and impact.
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