Exercise 3.49. Give a scenario where the deadlock-avoidance mechanism described above does not work. (Hint: In the exchange problem, each process knows in advance which accounts it will need to get access to. Consider a situation where a process must get access to some shared resources before it can know which additional shared resources it will require.)
要は，アクセスする資源の順序が最後まで定まらないシナリオってことか．最初にアクセスする口座の残高によって，どこの口座にお金を移すかが決まるようなシナリオとかかなー．
