os slip3

Q. 1 Creating a child process using the command exec(). Note down process ids of the parent and the child processes, check whether the control is given back to the parent after the
child process terminates.
ANSWER-1

#include <stdio.h>
#include <unistd.h>
int main() {
pid_t child_pid = fork();
if (child_pid == 0) {
printf("Child process (PID: %d)\n", getpid());
execl("/bin/ls", "ls", NULL); // Replace with the desired command
} else if (child_pid > 0) {
printf("Parent process (PID: %d)\n", getpid());
wait(NULL);
printf("Child process has terminated.\n");
} else {
perror("Fork failed");
return 1;}
return 0;}

Q.2 Write the simulation program using FCFS. The arrival time and first CPU bursts of different jobs should be input to the system. Assume the fixed I/O waiting time (2 units). The next
CPU burst should be generated using random function. The output should give the Gantt chart,Turnaround Time and Waiting time for each process and average times.
ANSWER-2

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define MAX_PROCESSES 10
typedef struct {
int arrival, burst, turnaround, waiting;
} Process;
int main() {
int n;
printf("Enter the number of processes: ");
scanf("%d", &n);
Process p[MAX_PROCESSES] = {0};
srand(time(NULL));
for (int i = 0; i < n; i++) {
p[i].arrival = i;
p[i].burst = rand() % 10 + 1; }
printf("Gantt Chart:\n");
float tTAT = 0, tWT = 0, t = 0;
for (int i = 0; i < n; i++) {
printf("P%d ", i + 1);
t += p[i].burst + 2; // Add I/O waiting time
p[i].turnaround = t - p[i].arrival;
p[i].waiting = p[i].turnaround - p[i].burst;
tTAT += p[i].turnaround;
tWT += p[i].waiting;}
printf("\n");
printf("Process\tTurnaround\tWaiting\n");
for (int i = 0; i < n; i++) {
printf("P%d\t%d\t\t%d\n", i + 1, p[i].turnaround, p[i].waiting);}
printf("Avg TAT: %.2f\nAvg WT: %.2f\n", tTAT / n, tWT / n);
return 0;