Overview of Scheduling Algorithms
In a mono-processor system, scheduling algorithms are crucial for managing the execution of processes. The goal is to maximize CPU utilization and minimize waiting time, response time, and turnaround time.
Understanding the Options
- a) Preemptive Algorithm: This allows a currently running process to be interrupted and replaced by another process. While it can improve responsiveness, it doesn't guarantee optimal scheduling.
- b) LST (Least Slack Time): This algorithm schedules processes based on their slack time, which is the amount of time remaining before a deadline. Though effective in some scenarios, it may not always yield optimal results.
- c) EDD (Earliest Due Date): EDD schedules tasks based on their due dates. While it performs well in minimizing lateness, it is not the optimal policy for all scenarios.
- d) LL (Least Laxity): The Least Laxity scheduling algorithm is considered optimal in mono-processor systems. Laxity is the time remaining until a task's deadline minus the time required to complete it. This approach prioritizes tasks that are closest to their deadlines, effectively reducing the chance of missing a deadline.
Why LL is Optimal
- Minimizes Missed Deadlines: By focusing on tasks with the least laxity, LL ensures timely execution.
- Dynamic Adjustments: It adjusts priorities dynamically, allowing the system to respond to changes in process execution times.
- Works Well Under Constraints: LL is particularly effective in real-time systems where meeting deadlines is critical.
In conclusion, the Least Laxity scheduling algorithm (option D) is optimal for mono-processor systems due to its focus on deadlines and efficient resource utilization.