Process Scheduling Algorithms

Lesson 2 · OKSTEM College · AS Computer Science

Work through the concepts, then test yourself with the knowledge check.

Knowledge Check

In Round-Robin scheduling, what determines the maximum time a process runs before being preempted?

Priority determines scheduling order in priority queues, not RR time slice.

Correct — when the quantum expires the process moves to the back of the ready queue.

Memory size doesn't affect CPU scheduling in standard RR.

File count is unrelated to RR scheduling.

📖 Quick Recap

Round-Robin doesn't use priorities. Each process gets an equal time quantum (e.g., 10ms). Priority scheduling is a separate algorithm.

📖 Quick Recap

CPU scheduling in RR is time-based, not memory-based. Memory affects page faults but not the scheduling quantum.

📖 Quick Recap

RR uses a fixed time quantum. Open files are an OS resource tracked in the PCB but don't influence scheduling quantum.

Shortest Job First (SJF) scheduling minimizes:

SJF doesn't reduce context switches; Round-Robin may actually use fewer if quantum is large.

Correct — SJF is provably optimal for minimizing average waiting time.

SJF can starve long processes; MLFQ or RR better serves interactive workloads.

Memory usage is not a scheduling concern for SJF.

📖 Quick Recap

SJF optimizes for average waiting time by running the shortest process next. Context switch count depends on process count, not job length.

📖 Quick Recap

Interactive response is better served by preemptive algorithms that give CPU time quickly to newly arriving tasks. SJF optimizes batch throughput.

📖 Quick Recap

SJF is purely about CPU burst time ordering. Memory management is handled separately by the memory manager.