Periodic Tasks – Real-time Systems MCQs

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1. What is a periodic task in real-time systems?
(A) A task that executes only once
(B) A task triggered by external events
(C) A task that executes at regular, fixed intervals
(D) A task with variable execution time

2. The interval between successive executions of a periodic task is called:
(A) Deadline
(B) Laxity
(C) Period
(D) Response time

3. The time required to complete a periodic task is called:
(A) Period
(B) Execution time
(C) Deadline
(D) Laxity

4. A periodic task may have a deadline:
(A) Always equal to its execution time
(B) Always greater than its period
(C) Always less than its period
(D) Less than, equal to, or greater than its period

5. Periodic tasks are usually scheduled using:
(A) LLF only
(B) RMS and EDF
(C) Batch scheduling
(D) Round-robin scheduling only

6. Which of the following is TRUE about periodic tasks?
(A) They are executed irregularly
(B) They are only for background processing
(C) They never have deadlines
(D) They are predictable in timing

7. In RMS, priority is assigned to periodic tasks based on:
(A) Shortest execution time
(B) Random selection
(C) Earliest arrival time
(D) Shortest period

8. In EDF, periodic tasks are scheduled according to:
(A) Execution time
(B) Absolute deadlines
(C) Period
(D) Task ID

9. Which parameter is critical to determine schedulability of periodic tasks?
(A) Arrival time only
(B) Memory size
(C) Period and execution time
(D) CPU speed only

10. If a periodic task’s execution time exceeds its period, then:
(A) The task set is unschedulable
(B) All deadlines can still be met
(C) Task priority is automatically increased
(D) CPU utilization decreases

11. The response time of a periodic task is:
(A) CPU idle time
(B) Task period
(C) Laxity
(D) Time from release to completion

12. Periodic tasks are predictable because:
(A) Execution order is random
(B) Deadlines are ignored
(C) Their arrivals are known in advance
(D) Tasks never preempt each other

13. Which scheduling algorithm guarantees deadlines for periodic tasks if total utilization is below the bound?
(A) RMS
(B) Round-robin
(C) LLF only
(D) FCFS

14. In a real-time system, periodic tasks are used for:
(A) Batch processing only
(B) Control loops in embedded systems
(C) General-purpose computing
(D) File transfer scheduling

15. What happens if a periodic task overrun occurs?
(A) Deadlines are unaffected
(B) CPU utilization improves
(C) Subsequent tasks may miss deadlines
(D) Execution time decreases

16. Which type of periodic task is most common in real-time systems?
(A) Independent and preemptive
(B) Dependent and non-preemptive
(C) Sporadic only
(D) Background tasks

17. The minimum interval between periodic task releases is called:
(A) Execution time
(B) Period
(C) Laxity
(D) Deadline

18. Periodic tasks are often combined with which other task types in real-time systems?
(A) Non-preemptive tasks only
(B) Background tasks only
(C) Aperiodic and sporadic tasks
(D) Batch tasks only

19. Which parameter of periodic tasks affects CPU utilization the most?
(A) Memory size
(B) Period and execution time
(C) Disk speed
(D) Task ID

20. Which statement about periodic tasks is TRUE?
(A) They are unpredictable and cannot be scheduled
(B) Deadlines are irrelevant
(C) They have known release times and predictable behavior
(D) Execution time is always zero