Calculating Waiting Time and Turnaround Time in non-preemptive FCFS queue

Question

I have 6 processes as follows   -- P0 --   arrival time   0    burst time   10    -- P1 --   arrival time   110    burst time   210    -- P2 --   arrival time   130    burst time   70    -- P3 --   arrival time   130    burst time   70  -- P4 --   arrival time   130    burst time   90  -- P5 --   arrival time   130    burst time   50   How can I calculate the waiting time and turnaround time for each process  The system should be non-preemptive  the process gets the CPU until it s done   Also  there are 4 logical processors in this system   Assume systemTime is the current systems uptime  and arrivalTime is relative to that  ie  an arrivalTime of 0 means the process starts when the system does  an arrivalTime of 130 means the process is started 130 units after the system starts   Is this correct  waitingTime    systemTime - arrivalTime     My reasoning for thinking this is that systemTime - arrivalTime is the time the process has been waiting in the fcfs queue to use the CPU  or is this wrong    And for turnaround time  I was thinking something like  turnaroundTime   burstTime   waitingTime  since the waiting time and the burst time should be the total time to complete the process  Though once again I don t know if my intuition is correct   Any and all readings would be greatly appreciated

User · Answer

wt   tt - cpu tm  Tt   cpu tm   wt    Where wt is a waiting time and tt is turnaround time  Cpu time is also called burst time

User · Answer

For non-preemptive system   waitingTime   startTime - arrivalTime  turnaroundTime   burstTime   waitingTime   finishTime- arrivalTime   startTime   Time at which the process started executing  finishTime   Time at which the process finished executing  You can keep track of the current time elapsed in the system timeElapsed   Assign all processors to a process in the beginning  and execute until the shortest process is done executing  Then assign this processor which is free to the next process in the queue  Do this until the queue is empty and all processes are done executing  Also  whenever a process starts executing  recored its startTime  when finishes  record its finishTime  both same as timeElapsed   That way you can calculate what you need

[algorithm] Calculating Waiting Time and Turnaround Time in (non-preemptive) FCFS queue

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