counting semaphore

The P and V operations on counting semaphores, where s is a counting semaphore, are defined as follows: P(s): s = s-1; if s < 0 then wait; V(s) : s = s-1; ifs <= 0 then wakeup a pr...

At a particular time of computation the value of a counting semaphore is 7. Then 20 P operations and 15 V operations were completed on this semaphore. The resulting value of the se...