1o Protection JO保护 e All lo instructions are privileged instructions 所有ⅣO指令是特权指令 e Must ensure that a user program could never gain control of computer in monitor model\w a user program that, as part of its execution, stores a new address in the interrupt vector °必须确保用户程序决不能以管态控制计算机(即,用户程序的执 行部分在中断向量中存放一个新的地址) Applied Operating System Concepts 2.18Applied Operating System Concepts 2.18 I/O Protection I/O保护 • All I/O instructions are privileged instructions. 所有I/O指令是特权指令 • Must ensure that a user program could never gain control of the computer in monitor mode (I.e., a user program that, as part of its execution, stores a new address in the interrupt vector). • 必须确保用户程序决不能以管态控制计算机（即，用户程序的执 行部分在中断向量中存放一个新的地址）