##### Gate2003_82

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: Process Q:
while (1) { while (1) {
W: Y:
print ‘0’; print ‘1’;
print ‘0’; print ‘1’;
X: 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 01^{n}0 or 10^{n}1 where n is odd?

(A) P(S) at W, V(S) at X, P(T) at Y, V(T) at Z, S and T initially 1

(B) P(S) at W, V(T) at X, P(T) at Y, V(S) at Z, S and T initially 1

(C) P(S) at W, V(S) at X, P(S) at Y, V(S) at Z, S initially 1

(D) V(S) at W, V(T) at X, P(S) at Y, P(T) at Z, S and T initially 1

**Answer**

Discuss

https://youtu.be/6Gv3G0_Nkck

Solution to this que from 7:20