A uni-processor computer system only has two processes, both of which alternate $$10$$ $$ms$$ $$CPU$$ bursts with $$90$$ $$ms$$ $${\rm I}/O$$ bursts. Both the processes were created at nearly the same time. The $${\rm I}/O$$ of both processes can proceed in parallel. Which of the following scheduling strategies will result in the least $$CPU$$ utilization (over a long period of time) for this system?

Suppose we want to synchronize two concurrent processes P and Q using binary semaphores S and T. The code for the processes P and Q is shown below.

Process P:

while(1){
  W:
  Print '0';
  Print '0';
  X:
}

Process Q:

while(1){
  Y:
  Print '1';
  Print '1';
  Z:
}

Synchronization statements can be inserted only at points W, X, Y, and Z.

Which of the following will ensure that the output string never contains a substring of the form 01ⁿ0 or 10ⁿ1 where n is odd?

Suppose we want to synchronize two concurrent processes P and Q using binary semaphores S and T. The code for the processes P and Q is shown below.

Process P:

while(1){
  W:
  Print '0';
  Print '0';
  X:
}

Process Q:

while(1){
  Y:
  Print '1';
  Print '1';
  Z:
}

Synchronization statements can be inserted only at points W, X, Y, and Z.

Which of the following will always lead to an output starting with 001100110011

Consider the C program shown below.

#include < stdio.h >
#define print(x) printf("%d ", x)
int x;
void Q(int z) {
   z += x; print(z);
}
void P(int *y) {
   int x = *y+2;
   Q(x); *y = x-1;
   print(x);
}
main(void) {
   x = 5;
   P(&x);
   print(x);
}

The output of this program is