19-06-2012, 01:37 PM
Priority Scheduling Algorithm
Priority Scheduling Algorithm.docx (Size: 10.73 KB / Downloads: 28)
Description:
In priority scheduling algorithm each process will be having a priority value along with its Burst time. Therefore ach process will be allocated the CPU time in consideration with their priority value. If the priority value is same for two processes, then the FCFS method will be implemented.
Turn Around Time:
The time interval between process submission and completion.
The first process will be having the submission time “0”and its completion time. The submission time for the second process will be starting from the completion time of the first process. In this way the time interval for each process, will be added and finally gives the Turn around Time. Then the average Turn around Time is calculated i.e., Turn Around time/number of processes, which is the average completion time of a process.
In order to calculate the waiting time, burst time, Turn around time, we have to build a Gantt chart in which the processes are arranged according to their priority values. The main disadvantage with this method is the process with the least priority value will not be given the CPU time easily. It has to wait for along time. This phenomenon is called “Starvation”. To overcome this, the priority of the processes will be increasing with their waiting time in the queue, so they will be allocated the CPU time. This phenomenon is called “Aging”.