#cs#os#hardware#architecture
Interrupts: The Alarm That Wakes the CPU
When the CPU is 100% busy and you move the mouse, does it respond? Polling vs Interrupts explained.
February 11, 2025
Codemapo
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| Type | Polling | Interrupt |
|---|---|---|
| Analogy | Asking "Are you there?" constantly | "Ring the bell when you arrive" |
| Initiator | CPU checks manually | Device calls the CPU |
| Efficiency | Huge waste while waiting | Very Efficient (Reacts only when needed) |
| Impl | while loop | Hardware/Software Signal |
What I ultimately understood about interrupts is this: "Wake me up when something important happens. Until then, I'll do my work."
This is the most efficient workflow in the world. The multitasking, asynchronous programming, and event-driven architecture we take for granted all stem from this philosophy.
Polling is anxious. It needs constant checking for reassurance. Interrupts are relaxed. They trust they'll be contacted when needed and focus on their work.
Apply this philosophy when writing code. Instead of infinite loops checking state, use event listeners or callbacks. That's what CPUs have been doing for decades.