Use your research skills to answer the following questions. a) Explain why Windows, Linux, and Solaris implement multiple locking mechanisms. Describe the circumstances under which they use spinlocks, mutex locks, semaphores, adaptive mutex locks, and condition variables. In each case, explain why the mechanism is needed. (6 marks) b) What are the advantages and disadvantages of busy waiting? Can busy waiting be avoided altogether? Explain your answer? (6 marks) c) What are the primary drawback of spinlocks and how to avoid it using two different ways at least? Why they are not appropriate for single-processor systems. (6 marks) d) Show that, if the wait () and signal() semaphore operations are not executed atomically, then mutual exclusion may be violated. (4 marks) e) Illustrate how a binary semaphore can be used to implement mutual exclusion among n processes? (6 marks) f) Provide at least three references you used, written in Harvard System. (not including Wikipedia)