Mutual Exclusion

Two published mutual exclusion protocols are given above. Your job is decide if they are both correct, one incorrect and the other correct or they are both correct. You should make your decision then write a position page defending your decision. On Friday, September 5, we will discuss your progress so far. The position page is due in class on Wednesday, September 10.

You’ll be graded on whether or not you made the correct decision and how you justified your decision. I hope you’ll be brutally honest in how you arrived at your conclusion.

The initial calls for both protocols is:

mutex (1,2); mutex (2,1);

In which two processes, 1 and 2, compete for access to their critical sections. The mutex2 protocol is initialized to

lock[1] = lock[2] = false and access := either 1 or 2.

The mutex1 protocol is initialized to

signal[1] = signal[2] = false and turn := 1.