Chapter 20, Problem 15E

Explanation of Solution

Access to shared memory area:

• Access to shared memory is controlled by using semaphores synchronization primitives or locks.
• The semaphore or locks are used for serializing access to the data structures in shared memory.
• When a shared memory is being accessed by a process, a semaphore or lock on it prevents other processes or disk from accessing it.
• A processor counter associated with a semaphore or lock on its prevents other processes or disk from accessing it.
• A processor counter associated with a semaphore keeps track of all processes which want access the shared memory...