Part One: 进程
1. Process concept
1.1 Process denion
1.1.1 Denion: process is a program in execuon. It must progress in sequenal
fashion
1.1.2 A process includes: PCB, Stack, Program and Data
1.2 进程与程序的区别
进程更能真实地描述并发,而程序不能;程序是静态的,进程是动态的;进程有生
命周期,有诞生有消亡,短暂的,而程序是相对长久的;进程具有创建其他进程的
功能,而程序没有
1.3 进程状态
New: the process is being created
Running: instrucons are being executed
Waing: the process is waing for some event to occur
Ready: the process is waing to be assigned to a process
Terminated: the process has nished execuon
1.4 PCB
1.4.1 PCB 内容: Informaon associated with each process. Process state, program
counter, CPU registers, CPU scheduling informaon, etc.
1.4.2 PCB 表:系统把所有 PCB 组织在一起,并放在内存固定区域,就构成了 PCB
表。PCB 的大小决定了系统中最多可同时存在的进程个数,称为系统的并
发度。
1.5 Process context
1.5.1 定义:对进程执行活动全过程的静态描述;由进程用户地址空间内容,硬
件寄存器内容及与该进程相关的核心数据结构组成。
1.5.2 CPU switch from process to process