模拟实现用同步机构避免并发进程执行时可能出现的与时间有关的错误。模拟PV操作同步机构的实现，模拟进程的并发执行，了解进程并发执行时同步机构的作用。-Simulation using the process of synchronization to avoid complications that may arise in the implementation of time-related error. Simulation of PV body to achieve synchronous operation, the concurrent implementation of the modeling process to understand the complicated process of implementation of the role of synchronization.