Chapter 5 Scheduling Flashcards
What is one possible goal of the RR policy?
Equal distribution of CPU.
List one advantage and one disadvantage of FCFS.
Advantage: Easy to implement, all services get executed;
Disadvantage: Not a fast method, ignores service time and isn’t a great performer.
Define the two kinds of processor affinity.
Soft: Migrate between process.
Hard: Run one process at a time.
What are the two ways load balancing can be achieved?
Push migration
Pull migration
What is the wait time of a process?
The sum of the periods spent waiting in the ready queue.
What is the turnaround time of a process?
The sum of the periods spent waiting to get into memory, waiting in the ready queue, executing on the CPU, and doing I/O.
What is the response time of a process?
The time it takes to start responding, not the time it takes to output the response.
Give an advantage and disadvantage of the shortest job next algorithm.
Advantage: Minimizes wait time.
Disadvantage: May starve large jobs, difficulty determining service times.
Give an advantage and disadvantage of the deadline scheduling algorithm.
Advantage: Allocates service by deadline.
Disadvantage: May not be feasible.
Explain the impact of quantum size
Too Large:
Processes complete but all other processes have a long wait.
Too Small:
May increase the number of ready processes.
Give an advantage and disadvantage of the Round Robin algorithm.
Advantages: Equitable
Most widely-used
Fits naturally with interval timer
Disadvantages: overhead
Give an advantage and disadvantage of the Priority scheduling algorithm.
Advantages: Reflects importances of external use, can address starvation with aging.
Disadvantages: May cause starvation
Define the two types of real time scheduling.
Hard real-time systems – required to complete a critical task within a guaranteed amount of time.
Soft real-time computing – requires that critical processes receive priority over less fortunate ones.
Define the two types of priority schemes.
Static: priority set up and does not change.
Dynamic: priority can change over time.
