ITPEC IP April 2022 Question 11

When two cache levels are used, the processor first checks the primary cache and then the secondary cache. The primary cache, commonly L1, is smaller and faster and is located closest to the processor core. If the requested data is not found there, the processor checks the larger but somewhat slower secondary cache, commonly L2, before accessing main memory. Therefore blanks A and B are primary cache and secondary cache respectively.

Answer (c)

Why not others:
- checking the secondary cache first would defeat the purpose of the faster primary level
- main memory is consulted only after the cache hierarchy misses
- virtual memory uses secondary storage to extend memory capacity and is not the first cache level

Key rule: A cache hierarchy is searched from the smallest and fastest level nearest the CPU toward larger, slower levels and finally main memory.

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