ITPEC FE Morning October 2023 Question 18

The CPU goes to the first process in the queue on each timer interrupt — round robin gives processes equal time slices in turn.

Ready processes wait in a first-in, first-out queue. The process at the head runs for one time quantum; when the interval timer interrupts, it is preempted and moved to the back of the queue, and the CPU is given to the process now at the head. The cycle repeats, so every process gets a share of the CPU.

Answer (c)

Why not others:

• •(a) — describes event-driven priority scheduling, where the order depends on priorities set in advance
• •(b) — describes shortest processing time first (shortest job first)
• •(d) — describes preemptive dispatching of an urgent process when an interrupt arrives, as in real-time systems

Key rule: Round robin is defined by a fixed time quantum enforced by the interval timer and a circular FIFO queue; priority and job length play no part.

Software · AI-written, may contain errors