操作系统试卷2007卷

1、东 北 大 学 考 试 试 卷 （A卷 ）20072008学年 第 二 学期课程名称：Operating System. Multiple Choice （10 points,1 point each）Directions: There are 10 questions. For each question there are 4 choices marked A, B, C and D. You should make the correct choices (one or more choices may be correct) and write down the correspondi

2、ng letters.6(B) What refers to the page replacement algorithm which replaces the page that has notbeen used for the longest period of time?(A) FIFO(B) LRU(C) OPT(D) LFU密1(BCD ) What are the major activities of an operating system?7(BCD) Which of the followings is a condition for deadlock？(A) User ma

3、nagement(C) I/O system management(B) Main memory management(D) File management(A) Starvation(B) Circular Wait(C) No Preemption(D) Mutual Exclusion8(A) The basic function of the file system is accessing files by names. The function can2(ABC ) The way that operating system components are interconnecte

4、d andbe realized by(A) directory-managing(C) file-protectingmodeled into a kernel can be(A) Simple structure(C) Layered approach(B) boosting the speed of the file-accessing(D) improving the utilization of storage(B) Microkernels(D) Prototype approach9(B) Preemption allocation strategies can be appli

5、ed to3(toC) What state is a process in when it can not run because it needs a resourcee available？(A) Main memory space(C) I/O system management(B) CPU management(D) Tape management封(A) Ready(B) Interrupt(C) Blocked(D) Running10(ABC ) Which of the following strategies need base register and length r

6、egister?4(ABC ) Which are the major differences between user-level threads and(A) paging(B) segmentation(D) fixed-sized partitions memory-managementkernel-level threads?(A) User-level threads kernel threads.(C) segmentation with pagingare unknown by the kernel, whereas the kernel is awareof. Concept

7、 Explanations （12 points, 3 points each）Directions: Explain the following concepts by giving the Chinese saying and describing the main features.User threads are scheduled by the thread library and the kernel schedules kernel threads.Kernel threads need not be associated with a process whereas every

8、 user thread belongs to a process.One user-level thread can be only mapped be one kernel thread.1System call线进程与操作系统之间的接口5(ABCD ) Which of the following free-space management strategies are supportedby an operating system?(A) Bit Vector(B) Linked list(C) Grouping(D) Counting学 院班 级学 号姓 名总分一二三四2What i

9、s the cause of trashing? How does the system detect thrashing? Once it thrashing, what can the system do to eliminate this problem?detects2Critical section进程中关于临界资源的代码段3Directory是为了对文件实施有效管理，将他们妥善的管理起来密4Overlay为了能让进程比他所分配到的内存空间大。基本思想：任何时候只在内存中保存所需的指令和数据，当需其他指令时，他们会装入到刚刚不再需要的指令的内存空间内3What is SPOOLing

10、? Describe how SPOOLing works using printer as an example.封. Brief Answers （20 points, 5 points each） Directions: Answer the following questions briefly.1Whats the difference between process and program? Whats the difference between process and thread?A程序是完成所需求的功能时，所应采取的顺序步骤，是执行指令的有序集合。进程是执行中的程序。包括程

11、序计数器，进程堆栈段 数据段程序和进程区别：程序是一个静态的概念，作为一种资源可以永久的存放在磁盘中。进程是程序执行的动态活动过程，随程序执行而发生，随程序执行结束而消亡静止状态的程序和数据是相互独立的信息集合，进程中的程序和数据是一个不可分割的实体，一个程序可以对应多进程进程是4Consider a system consisting of 4 resources of the same type that are shared by three processes, each of which needs at most 2 resources. Show that the system

12、is deadlock free.线学 院班 级学 号姓 名. Comprehensive Questions（58 points）2(10 points) Consider the following snapshot of a system:AllocationMaxR3 15555AvailableR1R2R3R4R1 02020R2 00033R3 10353R4 20442R1 02640R2 07636R4 20662P0 P1 P2 P3P421001 (5 points)Consider a memory management system with paging. There

13、 are threejobs, J1, J2 and J3, are in the memory now. J2 has 4 pages, which are stored in the 3rd,4th, 6thand 8th block of the main memory respectively. Suppose the page size is 1024bytes, and the main memory is 10k bytes, please answer the following two questions:密(1) Draw the page table of J2;Answ

14、er the following questions using the bankers algorithm:How many instances of each resource type in the system?What is the content of the matrix Need?Is the system in a safe state? Why?If a request from process P2 arrives for (0,1,0,0), can the request be granted immediately?(2) If J2 meets the instr

15、uction “MOV 2100, 3100” (decimal) at its logical address500 (decimal), give the physical addresses of the two operands above.封线.学 院班 级学 号姓 名4(20 points) Consider the following set of processes, with the length of the CPU-burst timegiven in milliseconds:3(15 points) Consider the following page refere

16、nce string:、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、 、1、3Please write processes of the following replacement algorithms and give the number of page faults, assuming three frames? Remember all frames are initially empty, so your first unique pages will all cost one fault each.FIFO replacementLRU replacementO

17、ptimal replacementProcess P1P2 P3 P4P5Arrival time 02468Burst time (ms) 36452Priority 35124密Draw Gantt charts illustrating theexecution of these processes of the following schedulingalgorithms, and calculate the waiting time of each process as well as the average waiting time of each scheduling algorithms.Preemptive and non-preemptive SJFPreemptive priority (a smaller priority number implies a higher priority)RR (quantum = 4ms)封线学 院班 级学 号姓 名密5(8 points) Consider four processes A, B, C and D, sharing a same buffer. Process A inputs one object into the buffer each time,