Protection System 保护系统 e Protection refers to a mechanism for controlling access by programs, processes, or users to both system and user resources 保护是一种机制,控制程序、进程、或用户对系统和用户资源的 访问 ° The protection mechanism must保护机制必须: distinguish between authorized and unauthorized usage.区分授权和非授权使用 specify the controls to be imposed.确定要采用的控制 provide a means of enforcement.提供强制手段 Applied Operating System Concepts 3.8Applied Operating System Concepts 3.8 Protection System 保护系统 • Protection refers to a mechanism for controlling access by programs, processes, or users to both system and user resources. 保护是一种机制，控制程序、进程、或用户对系统和用户资源的 访问 • The protection mechanism must 保护机制必须: – distinguish between authorized and unauthorized usage. 区分授权和非授权使用 – specify the controls to be imposed. 确定要采用的控制 – provide a means of enforcement. 提供强制手段