Subject Operating Systems a = 1 b = 0 count = 0 Code section P: For process 1 Wait (a) ⇒ a = 0 wait (b) process blocked As shown above, all processes execute wait (b) before, signal (b) in if condition. Because, ‘if’ condition becomes True only for process Pn(nth process) [∵ if (count = = n)] So, before Pn process finishes the code section, P, no other process executes code section Q. Hence, no process executes code section Q before every process has finished code section P.