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.
|
Method used by PI |
Method used by P2 |
|
While (S1 == S2); Critical Section S1 = S2; |
While (S1 != S2); Critical Section S2 = not (S1); |
Which one of the following statements describes the properties achieved?
1
Mutual exclusion but not progress
2
Progress but not mutual exclusion
3
Neither mutual exclusion nor progress
4
Both mutual exclusion and progress