Types of Scheduling
- Long-term scheduling - the adding and removing of processes to the pool of processes
- Medium-term scheduling - the adding and removing processes partially or fully from memory
- Short-term scheduling - the execution of a process by the CPU
- I/O scheduling - choosing which process will be handled by the available I/O devices
Scheduling Criteria
- response time - time from point of submission to when the results are received (start)
- turnaround time - time from point of submission to when the results are completed (end)
- deadline - maximize percentage of deadlines met
User Oriented, Other
- Predictability - a job should run the same regardless of the load
System Oriented, Performance Related
- throughput - amount of processes completed per time unit
- processor utilization - ratio of time processor is busy
System Oriented, Other
- fairness - no process should starve
- enforcement of priorities - scheduling policy should favor processes of higher priority
- balancing resources - keep resources busy.
