Q23

Consider the methods used by processes $P1$ and $P2$ for accessing their critical sections whenever needed, as given below. The initial values of shared boolean variables $S1$ and $S2$ are randomly assigned.

$$\begin{array}{|l|l|}\hline \textbf{Method used by P1} & \textbf{Method used by P2} \\ \hline \text{while (S1 == S2);} & \text{while (S1 != S2);} \\ \text{Critical Section} & \text{Critical Section} \\ \text{S1 = S2;} & \text{S2 = not(S1);} \\\hline \end{array}$$

Which one of the following statements describes the properties achieved?