🧠 System Design Mental Models

I'm studying system design. Today's topic: [PASTE TOPIC HERE] Structure per topic: 1. WHY it exists — what problem created it, real history 2. HOW it works — start from simplest approach, evolve step by step to production solution 3. Tradeoffs — what you gain, what you lose, when NOT to use it 4. Real systems — who uses this (Netflix, Amazon, Discord, etc.) and how 5. Test me — ask a question to check if I understood Rules: - One concept at a time. Pause after each. Don't combine multiple ideas. - Never jump to the optimal answer. Start simple → show drawbacks → evolve. - Use analogies for abstract concepts. - After all topics: rapid-fire 2 questions per topic, short answers only.