os slip15

1.Write a program to create a child process using fork().The parent should goto sleep state and child process should begin its execution. In the child process, use execl() to execute the “ls”
command.
ANSWER-1

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
int main() {
pid_t child_pid = fork();
if (child_pid < 0) {
perror("Fork failed");
exit(1);
} else if (child_pid == 0) {
printf("Child Process (PID %d) is running and executing 'ls'.\n", getpid());
execl("/bin/ls", "ls", (char *)NULL);
perror("execl() failed");
exit(1);
} else {
printf("Parent Process (PID %d) is going to sleep.\n", getpid());
sleep(2);
printf("Parent Process (PID %d) is awake.\n", getpid());}
return 0;}

2.Write the simulation program to implement demand paging and show the page scheduling and total number of page faults for the following given page reference string. Give input n as
the number of memory frames. Reference String :7, 0, 1, 2, 0, 3, 0, 4, 2, 3, 0, 3, 2 Implement LRU
ANSWER-2

#include <stdio.h>
#include <stdlib.h>
int main() {
int n, p = 0, r, q = 0;
printf("Enter the number of memory frames: ");
scanf("%d", &n);
int frames[n];
printf("Reference String: ");
while (scanf("%d", &r) != EOF) {
int found = 0;
for (int i = 0; i < n; i++) {
if (frames[i] == r) {
found = 1;
break;}}
if (!found) {
printf("Page %d -> Page Fault\n", r);
frames[p % n] = r;
p++;}
q++;}
printf("Total Page Faults: %d\n", p);
return 0;}