Why is an LLM's context window limited, and how do models extend it?
Context windows are not arbitrary figures; they follow from attention's quadratic cost, KV-cache memory, and how the model was trained. What shows depth is naming all three causes and matching each to the technique that extends it.
Updated Sep 2026 · Grounded in real GenAI, LLM, and AI/ML engineering interview loops and written to a senior-engineer editorial bar.
Context windows are not arbitrary figures; they follow from attention's quadratic cost, KV-cache memory, and how the model was trained. What shows depth is naming all three causes and matching each to the technique that extends it.
Lead with where the obvious approach breaks, because that is the judgment they are screening for — most candidates jump straight to the happy path and lose the room.
Then walk the failure back through the pipeline in order, naming the one metric the customer's exec sponsor actually cares about before you propose the fix.
