Section checkpoint

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6 questions drawn from the 2 chapters in this section. If most land on the first try, you are ready for the next section. If not, the explanation after each answer says which idea to revisit.

Checkpoint

6 questions · first-try answers earn the most XP

1. Why are interviewers grading your reasoning rather than your final diagram?

2. Which sentence most directly demonstrates the core tradeoff an interviewer is listening for?

3. What does the framework's final step, "what breaks first?", actually get you?

4. Why does the chapter emphasise that each network hop costs about a million cache hits?

5. You store 1 million user profiles averaging 1 KB each. How much storage is that?

6. Which operation is slowest on the latency ladder in this chapter?

What this checkpoint covers

What is System Design?
From app to millions: tradeoffs, not perfect answers.
Numbers Every Beginner Should Know
Latency numbers, 1M vs 1B, back-of-envelope.

Next section: Foundations