资讯系-作业系统/戴婵玲/94上期中考 来抛砖引玉一下... 一、解释名词(25%) a. PCB b. preemptive scheduling c. cascading termination d. dispatch latency e. convoy effort 二、问答题(75%) 1. 对於资源保护而言，双模(dual-mode)作业模式为何是必要的？它如何工作？我们为何 需要系统呼叫(system call)？ (15%) 2. 说明下列作业系统的优点和缺点：(10%) A.分层结构(layer approach) B.虚拟机(VM) 3. 何谓thread pool？他有何优点？既然称thread为轻量级行程，为何还需要用到thread pool？(15%) 4. 中断(interrupt)是电脑改变其执行指令的正规流程而产生的讯号(signal)。请描述中 段处理的基本程序。(10%) 5. 针对下列各行程到达与执行时的资讯，若采用SRTF、preemptive priority scheduling 等排班法 (15%) A.画出每一种排班法的甘特图。 B.计算每一行程在不同排班法的回复时间与等待时间。 C.计算各排班法的平均等待时间。 行程 到达时间 CPU Burst Time Priority -------------------------------------------------------- P1 0 5 3 P2 2 3 2 P3 3 1 1 P4 5 4 2 P5 6 6 2 6.选择题(10%) A.Which of the following items is not an operation of the dispatcher? (1) switching context (2) switching to the user mode (3) determining the degree of multiprogramming (4) jumping to the proper location in the user programming to restart that program B.Which of the following statement about threads is not correct? (1) There is no memory protection among the peer thread of a process. (2) Because kernel thread management is optimized by the operating system, kernel threads are generally faster to create and manage than user threads. (3) If a kernel thread performs a blocking system call, the kernel can schedule another thread in the application for execution. (4) Windows NT, Windows 2000 and Solaris 2 support kernel threads. C.Which of the following statements about CPU scheduling is not correct? (1) The average waiting time under FCFS scheduling is often quite long. (2) The SJF scheduling algorithm is optimal in terms of user response time. (3) A major problem with priority-scheduling algorithm is starvation. (4) The FCFS algorithm is particularly troublesome for time-sharing systems, where each user needs to get a share of the CPU at regular intervals. D.The following are common scheduling criteria: (i) urgency of a fast response (ii) is the process batch or interactive (iii) process priority (iv) accumulated waiting time (v) estimated run-time to completion For each of the following, indicate which of the preceding scheduling criteria is most appropriate. (1) Is user present and expecting fast interactive response time, or before its quantum expires? (2) One goal of process scheduling is to minimize average waiting times. 呼...还真多 @.@ -- http://www.wretch.cc/blog/danielhsieh 抓紧最後能够放松的日子!! --

※ 发信站: 批踢踢实业坊(ptt.cc) ◆ From: 218.163.152.117 ※ XX9:转录至看板 FCUProblems 01/16 20:26