内核讲解2第2章 实时系统概念 ...........................................................................................................1 2.0 前后台系统 （FOREGROUND/BACKGROUND SYSTEM） ............................................1 2.1 代码的临界段 ...............................................................................................................2 2.2 资源...............................................................................................................................2 2.3 共享资源.......................................................................................................................2 2.4 多任务...........................................................................................................................2 2.5 ……