CPU-Simulator was a program designed to show how the CPU works through jobs using the different scheduling algorithms available. The program was made for Sister Jane's COM 310 Operating Systems assignment #1.
https://jaredscar.github.io/CPU-Simulator/
- The higher the priority number, the more important the process is in a Priority Non-Preemptive and Priority Preemptive scheduling algorithm.
- Wait Time refers to the amount of time spent in the Ready Queue waiting to be processed by a CPU.
- Turn Around Time refers to the amount of time spent in the Ready Queue and getting processed by a CPU (time passed until fully completed).
- Burst times of each process can range from 1 time unit to 10 time units.
- Priority levels can range from 0-100.
"First Come First served" CPU scheduling algorithm works like its name the first job that arrives to the ready queue will be processed by the CPU.
"Non-Preemptive Priority" works just like "First Come First Served" algorithm except that the jobs in the ready queue are ordered by priority.
"Preemptive Priority" works like the "Shortest Remaining Time First" algorithm except that the jobs in the ready queue are ordered by priority. A job which is currently being processed by the CPU can be replaced for a job with a higher priority.
The "Round Robin" algorithm lets every job be processed by the CPU for a certain time "quantum time" then replaces it with the next job in the ready queue. When a job finishes it's quantum time it gets sent to the end of the ready queue.
The "Shortest Job First" algorithm is the same as "First Come First Served" except that the ready queue is reordered by shortest burst time job every time a new job arrives. "Shortest Job First" is a non-preemptive algorithm.
[Impossible to implement in interactive systems where required CPU time is not known]
"Shortest Time Remaining First" is the same as "Shortest Job First" except it orders the jobs in the ready queue by the shortest remaining time including the job that is getting processed by the CPU. A job in the ready queue will replace the job which is being currently processed by the CPU if it has a shorter remaining time. "Shortest Time Remaining First" is a preemptive algorithm.