Recovery Mechanisms – Real-time Systems MCQs

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1. What is the main purpose of recovery mechanisms in real-time systems?
(A) To batch process tasks only
(B) To reduce CPU idle exclusively
(C) To restore the system to a consistent state after a fault occurs
(D) To ignore deadlines

2. Which type of faults can recovery mechanisms handle?
(A) Only CPU idle exclusively
(B) Transient, intermittent, and permanent faults
(C) Disk batch failures exclusively
(D) Memory-only errors

3. Which recovery method involves restarting a task from its last checkpoint?
(A) Memory-only rollback
(B) CPU idle exclusively
(C) Disk batch-only recovery
(D) Rollback recovery

4. Forward recovery is characterized by:
(A) Disk batch-only recovery
(B) CPU idle exclusively
(C) Continuing execution with corrective actions without restarting the task
(D) Task suspension indefinitely

5. Primary-backup recovery involves:
(A) CPU idle exclusively
(B) Switching to a backup task if the primary task fails
(C) Disk batch-only switching
(D) Memory-only backup

6. Which of the following ensures system consistency after recovery?
(A) Logging and checkpointing mechanisms
(B) CPU idle exclusively
(C) Disk batch-only operations
(D) Memory-only snapshots

7. Recovery mechanisms are critical in:
(A) Batch-only desktop systems
(B) Hard real-time and safety-critical systems
(C) CPU idle exclusively
(D) Disk archival only

8. In rollback recovery, the system:
(A) CPU idle exclusively
(B) Restores task states to the most recent checkpoint
(C) Disk batch-only restoration
(D) Skips failed tasks

9. Redundant execution as a recovery mechanism means:
(A) Disk batch-only execution
(B) CPU idle exclusively
(C) Running multiple replicas of tasks to tolerate faults
(D) Memory-only replication

10. Which recovery strategy can handle transient faults efficiently?
(A) Retry or rollback recovery
(B) CPU idle exclusively
(C) Disk batch-only retries
(D) Memory-only checkpoints

11. Checkpointing combined with rollback recovery ensures:
(A) Memory fragmentation
(B) CPU idle exclusively
(C) Disk batch-only safety
(D) Minimal recomputation and timely recovery

12. Recovery mechanisms can be classified into:
(A) Disk batch-only recovery
(B) CPU idle exclusively
(C) Backward (rollback) and forward recovery
(D) Memory-only recovery

13. What is a major challenge in real-time recovery?
(A) Restoring tasks without violating deadlines
(B) CPU idle exclusively
(C) Disk batch-only recovery
(D) Memory-only defragmentation

14. Logging-based recovery helps by:
(A) Memory-only snapshots
(B) CPU idle exclusively
(C) Disk batch-only logging
(D) Recording events to reconstruct system state after a failure

15. Fault masking is a recovery mechanism that:
(A) CPU idle exclusively
(B) Hides the effect of faults from the system using redundancy
(C) Disk batch-only recovery
(D) Memory-only masking

16. In distributed real-time systems, coordinated recovery ensures:
(A) Disk batch-only restoration
(B) CPU idle exclusively
(C) Consistent recovery across dependent tasks
(D) Memory-only snapshots

17. Recovery mechanisms are essential to:
(A) Memory-only optimization
(B) CPU idle exclusively
(C) Disk batch-only tasks
(D) Maintain system reliability and predictability despite faults

18. Backup-based recovery is most effective when:
(A) Failures are likely but predictable, allowing standby tasks
(B) CPU idle exclusively
(C) Disk batch-only operations
(D) Memory-only snapshots

19. The main advantage of recovery mechanisms in real-time systems is:
(A) Memory-only saving
(B) CPU idle exclusively
(C) Disk batch-only optimization
(D) Ensuring system tasks complete correctly and on time despite faults

20. Recovery mechanisms must be carefully designed to:
(A) CPU idle exclusively
(B) Balance overhead with fault coverage and timing constraints
(C) Disk batch-only recovery
(D) Memory-only optimization