Preview
IB DP Computer Science — A1 Computer fundamentals — Operating systems and control systems | SL | A1.3.3
📋 What You Will Learn
- Explain why the OS schedules: allocating CPU time among processes to optimize system performance
- Define ready queue, preemptive vs non-preemptive scheduling, quantum, and the metrics waiting time, turnaround time and response time
- Describe first-come first-served (FCFS), round robin (RR), priority scheduling and multilevel queue scheduling
- Construct schedules and trace them, calculating average waiting and turnaround times
- Compare the four approaches and justify a choice for a given system
🔎 Why This Matters A supermarket with one till and one queue is FCFS — simple, but one giant trolley makes everyone wait. An express lane for small baskets is a multilevel/priority queue. A barista making three drinks by rotating a little work on each is round robin. Your OS faces the same trade-offs, thousands of times per second.
Why Schedule at All?
📖 Definition — CPU scheduling The OS activity of managing the execution of processes by deciding which ready process the CPU runs next, and for how long — allocating CPU time so as to optimize