Consider the following program snippet. Assume that the program compiles and runs successfully. Further, assume that the fork( ) system call is always successful in creating a process.

int main( ) {

int i;

for (i = 0; i < 3; i++){

    if (fork() == 0){

        continue;

    }

    break;

}

printf("Hello!");

return 0;

}

```

The total number of times that the printf statement gets executed is $\_\_\_\_$ . (answer in integer)

Consider a CPU that has to execute two types of processes. The first type, Actuators (A), requires a CPU burst of 6 seconds. The second type, Controllers (C), requires a CPU burst of 8 seconds. A new process of type A arrives at time $t=10,20,30,40$, and 50 (in seconds). Similarly, a new process of type C arrives at time $t=11,22,33$, 44, and 55 (in seconds). The CPU scheduling policy is First Come First Serve (FCFS). The first process of type A starts running at $t=10$ seconds. The average waiting time (in seconds) for the 10 processes is $\_\_\_\_$ . (rounded off to one decimal place)

A computer has two processors, $M_1$ and $M_2$. Four processes $P_1, P_2, P_3, P_4$ with CPU bursts of $20,16,25$, and 10 milliseconds, respectively, arrive at the same time and these are the only processes in the system. The scheduler uses non-preemptive priority scheduling, with priorities decided as follows:

$\bullet$ $M_1$ uses priority of execution for the processes as, $P_1>P_3>P_2>P_4$, i.e., $P_1$ and $P_4$ have highest and lowest priorities, respectively.

$\bullet$ $M_2$ uses priority of execution for the processes as, $P_2>P_3>P_4>P_1$, i.e., $P_2$ and $P_1$ have highest and lowest priorities, respectively.

A process $P_i$ is scheduled to a processor $M_k$, if the processor is free and no other process $P_j$ is waiting with higher priority. At any given point of time, a process can be allocated to any one of the free processors without violating the execution priority rules. Ignore the context switch time. What will be the average waiting time of the processes in milliseconds?

Consider a single processor system with four processes A, B, C, and D, represented as given below, where for each process the first value is its arrival time, and the second value is its CPU burst time.

A (0, 10), B (2, 6), C (4, 3), and D (6, 7).

Which one of the following options gives the average waiting times when preemptive Shortest Remaining Time First (SRTF) and Non-Preemptive Shortest Job First (NP-SJF) CPU scheduling algorithms are applied to the processes?