Lesson 039
Memory & Storage
Hierarchy · Cache · RAM · Virtual Memory
1:00How computers organize memory into a hierarchy — from CPU registers and cache down through RAM to SSD and HDD — and why each level exists.
By the end, you can
- Recite the memory hierarchy in order (registers → cache → RAM → SSD → HDD) and explain the speed/size/cost trade-off at each level.
- Explain why the CPU latency gap between cache (~1 ns) and RAM (~100 ns) makes a multi-level hierarchy necessary.
- Distinguish L1, L2, and L3 cache by size and scope (per-core vs shared).
- Define volatile and non-volatile memory and name which storage types fall into each category.
- Compare HDDs and SSDs, and explain why SSDs feel snappier for random-access workloads.
- Describe how virtual memory works, what a page fault is, and what causes thrashing.
- Choose appropriate RAM and storage sizes for light, gaming/creative, and storage-heavy workloads.
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