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IB DP Computer Science — A1 Computer fundamentals — Operating systems and control systems | SL | A1.3.4
📋 What You Will Learn
- Describe how polling detects events by repeatedly checking device status
- Describe the steps of interrupt handling : signal → save state → interrupt service routine (ISR) → restore
- Construct and read a simple polling loop in pseudocode, Java and Python
- Evaluate the two approaches against the six syllabus factors: event frequency, CPU overhead, power source, event predictability, controlled latency, security
- Apply the evaluation to real scenarios: keyboard/mouse input, network communications, disk I/O, embedded systems, real-time systems
🔎 Why This Matters Waiting for a parcel, you could walk to the door every five minutes to check (polling) — tiring, and you might still be five minutes late seeing it. Or you could fit a doorbell (interrupt) and get on with your day, dropping everything only when it rings. Neither is always better: if parcels arrived every few seconds, the constant ringing would be worse than