《操作系统概念》第六版作业解答16章.ppt
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c. Time sharing
使用CPU调度和多道程序提供对系统的经济交互式使用，CPU快 速地在用户之间切换
一般从终端读取控制，输出立即打印到屏幕
d. Real time
在专门系统中使用，从传感器读取信息，必须在规定时间内作出 响应以确保正确的执行
1-cont.
1.6 Define the essential properties of the following types of operating systems:
2-cont.
2.3 What are the differences between a trap and an interrupt? What is the use of each function?
An interrupt是硬件产生的系统内的流的改变 A trap是软件产生的“中断”。 interrupt可以被I/O用来产生完成的信号，从而避免CPU对设备的轮
a. What are two such problems? b. Can we ensure the same degree of security in a time-shared
machine as we have in a dedicated machine? Explain your answer. 用户之间互相偷数据、代码 对系统资源使用的记账信息
缺点：软硬件更复杂
Chapter 2
2.2 How does the distinction between monitor mode and user mode function as a rudimentary form of protection (security) system?
通过建立一组只能在monitor mode才能执行的特权指令集，OS能够 确保总是能控制整个系统。
a. Set value of timer. c. Clear memory. d. Turn off interrupts. e. Switch from user to monitor mode.
2-cont.
2.8 Protecting the operating system is crucial to ensuring that the computer system operates correctly. Provision of this protection is the reason behind dualmode operation, memory protection, and the timer. To allow maximum flexibility, however, we would also like to place minimal constraints on the user. The following is a list of operations that are normally protected. What is the minimal set of instructions that must be protected?
e. Network
在通用OS上添加
联网、通信功能 远程过程调用 文件共享
f. Distributed
具有联网、通信功能 提供远程过程调用 提供多处理机的统一调度调度 统一的存储管理 分布式文件系统
1-cont.
1.9 Describe the differences between symmetric and asymmetric multiprocessing. What are three advantages and one disadvantage of multiprocessor systems?
1-cont.
1.5 In a multiprogramming and time-sharing environment, several users share the system simultaneously. This situation can result in various security problems.
Symmetric multiprocessing中所有处理器同等对待，I/O可以 在任意CPU上处理。
Asymmetric multiprocessing具有一个主CPU和多个从CPU，主 CPU将任务分派到从CPU，I/O通常只能由主CPU处理。
多处理机系统的优点
比多个计算机系统可能更省钱（同样CPU个数） 执行程序更快 可靠性更高
批处理适合于需要极少用户交互的Job。
b. Interactive
由许多短交易组成，下一次交易的结果可能不可预知 需要响应时间短
Biblioteka Baidu
1-cont.
1.6 Define the essential properties of the following types of operating systems:
Chapter 1
1.1 What are the three main purposes of an operating system?
环境提供者，为计算机用户提供一个环境，使得能够在计算机硬 件上方便、高效的执行程序
资源分配者，为解决问题按需分配计算机的资源，资源分配需尽 可能公平、高效
控制程序
监控用户程序的执行，防止出错和对计算机的不正当使用 管理I/O设备的运行和控制
1-cont.
1.3 What is the main advantage of multiprogramming?
高效地使用CPU，通过重叠来自不同用户对CPU和I/O设备的需求 增加CPU的利用，设法让CPU执行有意义的指令
1-cont.
1.6 Define the essential properties of the following types of operating systems:
a. Batch
相似需求的Job分批、成组的在计算机上执行，Job由操作员或自动Job程序 装置装载；
可以通过采用 buffering, off-line operation, spooling, multiprogramming 等技术使CPU 和 I/O不停忙来提高性能
询 A trap可以用来调用OS的例程或者捕获算术错误
2-cont.
2.5 Which of the following instructions should be privileged?
a. Set value of timer. b. Read the clock. c. Clear memory. d. Turn off interrupts. e. Switch from user to monitor mode.
使用CPU调度和多道程序提供对系统的经济交互式使用，CPU快 速地在用户之间切换
一般从终端读取控制，输出立即打印到屏幕
d. Real time
在专门系统中使用，从传感器读取信息，必须在规定时间内作出 响应以确保正确的执行
1-cont.
1.6 Define the essential properties of the following types of operating systems:
2-cont.
2.3 What are the differences between a trap and an interrupt? What is the use of each function?
An interrupt是硬件产生的系统内的流的改变 A trap是软件产生的“中断”。 interrupt可以被I/O用来产生完成的信号，从而避免CPU对设备的轮
a. What are two such problems? b. Can we ensure the same degree of security in a time-shared
machine as we have in a dedicated machine? Explain your answer. 用户之间互相偷数据、代码 对系统资源使用的记账信息
缺点：软硬件更复杂
Chapter 2
2.2 How does the distinction between monitor mode and user mode function as a rudimentary form of protection (security) system?
通过建立一组只能在monitor mode才能执行的特权指令集，OS能够 确保总是能控制整个系统。
a. Set value of timer. c. Clear memory. d. Turn off interrupts. e. Switch from user to monitor mode.
2-cont.
2.8 Protecting the operating system is crucial to ensuring that the computer system operates correctly. Provision of this protection is the reason behind dualmode operation, memory protection, and the timer. To allow maximum flexibility, however, we would also like to place minimal constraints on the user. The following is a list of operations that are normally protected. What is the minimal set of instructions that must be protected?
e. Network
在通用OS上添加
联网、通信功能 远程过程调用 文件共享
f. Distributed
具有联网、通信功能 提供远程过程调用 提供多处理机的统一调度调度 统一的存储管理 分布式文件系统
1-cont.
1.9 Describe the differences between symmetric and asymmetric multiprocessing. What are three advantages and one disadvantage of multiprocessor systems?
1-cont.
1.5 In a multiprogramming and time-sharing environment, several users share the system simultaneously. This situation can result in various security problems.
Symmetric multiprocessing中所有处理器同等对待，I/O可以 在任意CPU上处理。
Asymmetric multiprocessing具有一个主CPU和多个从CPU，主 CPU将任务分派到从CPU，I/O通常只能由主CPU处理。
多处理机系统的优点
比多个计算机系统可能更省钱（同样CPU个数） 执行程序更快 可靠性更高
批处理适合于需要极少用户交互的Job。
b. Interactive
由许多短交易组成，下一次交易的结果可能不可预知 需要响应时间短
Biblioteka Baidu
1-cont.
1.6 Define the essential properties of the following types of operating systems:
Chapter 1
1.1 What are the three main purposes of an operating system?
环境提供者，为计算机用户提供一个环境，使得能够在计算机硬 件上方便、高效的执行程序
资源分配者，为解决问题按需分配计算机的资源，资源分配需尽 可能公平、高效
控制程序
监控用户程序的执行，防止出错和对计算机的不正当使用 管理I/O设备的运行和控制
1-cont.
1.3 What is the main advantage of multiprogramming?
高效地使用CPU，通过重叠来自不同用户对CPU和I/O设备的需求 增加CPU的利用，设法让CPU执行有意义的指令
1-cont.
1.6 Define the essential properties of the following types of operating systems:
a. Batch
相似需求的Job分批、成组的在计算机上执行，Job由操作员或自动Job程序 装置装载；
可以通过采用 buffering, off-line operation, spooling, multiprogramming 等技术使CPU 和 I/O不停忙来提高性能
询 A trap可以用来调用OS的例程或者捕获算术错误
2-cont.
2.5 Which of the following instructions should be privileged?
a. Set value of timer. b. Read the clock. c. Clear memory. d. Turn off interrupts. e. Switch from user to monitor mode.