通过对Linux的fork.c、exit.c代码的分析, 了解一个操作系统进程的创建、退出的过程； 锻炼学生分析大型软件代码的能力；通过与同组同学的合作, 锻炼学生的合作能力。-Based on Linux fork. C, exit. C code analysis, understand an operating system process to create and exit process　Training students the ability of analysis of large-scale software code　Through the group members and the cooperation, strengthen students　ability of cooperation.