Processes $P 1, P 2, P 3, P 4$ arrive in that order at times $0,1,2$, and 8 milliseconds respectively, and have execution times of $10,13,6$, and 9 milliseconds respectively. Shortest Remaining Time First (SRTF) algorithm is used as the CPU scheduling policy. Ignore context switching times.
Which ONE of the following correctly gives the average turnaround time of the four processes in milliseconds?

Suppose in a multiprogramming environment, the following C program segment is executed. A process goes into I/O queue whenever an I/O related operation is performed. Assume that there will always be a context switch whenever a process requests for an I/O, and also whenever the process returns from an I/O. The number of times the process will enter the ready queue during its lifetime (not counting the time the process enters the ready queue when it is run initially) is _________ . (Answer in integer)

int main( )
{
    int x = 0,i=0;
    scanf("%d", &x);
    for(i=0; i<20;i++)
    {
        x=x+20;
        printf("%d\n", x);
    }
    return 0;
}

Consider a process P running on a CPU. Which one or more of the following events will always trigger a context switch by the OS that results in process P moving to a non-running state (e.g., ready, blocked)?

Which of the following process state transitions is/are NOT possible?