The Trade-off Drill

The system design interview — the one where somebody asks you to design a whole system at a whiteboard — is not listening for whether you can name the tools. It is listening for whether you can choose between two of them out loud and say what the choice cost. This page is the drill for that, and it works on a walk.

• What it is: ten pairs of tools, and one sentence to say about each.
• Who fills it in: you, out loud first and on paper second. The sentence has to survive being said.
• When: ten minutes a day for the week before. Not the night before.
• Time: about four minutes per pair once you have the shape.