每章作业-课件PPT（精品）.ppt

Chapter 1 ? 1. What are the three main purposes of an operating system? ? 2. What is the main advantage of multiprogramming? ? 3. In a multiprogramming and time-sharing environment, several users share the system simultaneously. This situation can result in various security problems. ? 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. 1-cont. ? 4. Define the essential properties of the following types of operating systems: ? a. Batch ? b. Interactive ? c. Time sharing ? d. Real time ? e. Network ? f. Distributed ? 5. Describe the differences between symmetric and asymmetric multiprocessing. What are three advantages and one disadvantage of multiprocessor systems? ? 6. thinking: what kind of features may exist , IOT or CPS? Chapter 2 ? 1. How does the distinction between monitor mode and user mode function as a rudimentary form of protection (security) system? ? 2. What are the differences between a trap and an interrupt? What is the use of each function? ? 3. 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. 2-cont. ? 4. Protecting the operating system is crucial to ensuring that puter system operates correctly. Provision of this protection is the reason behind dual-mode 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? ? a. Change to user mode. ? b. Change to monitor mode. ? c. Read from monitor memory. ? d. Write into monitor memory. ? e. Fetch an instruction from monitor memory. ? f. Turn on timer interrupt. ? g. Turn off timer interrupt. Chapter 3 ? 1. What are the f