資訊系-作業系統/戴嬋玲/94上期中考 來拋磚引玉一下... 一、解釋名詞(25%) a. PCB b. preemptive scheduling c. cascading termination d. dispatch latency e. convoy effort 二、問答題(75%) 1. 對於資源保護而言，雙模(dual-mode)作業模式為何是必要的？它如何工作？我們為何 需要系統呼叫(system call)？ (15%) 2. 說明下列作業系統的優點和缺點：(10%) A.分層結構(layer approach) B.虛擬機(VM) 3. 何謂thread pool？他有何優點？既然稱thread為輕量級行程，為何還需要用到thread pool？(15%) 4. 中斷(interrupt)是電腦改變其執行指令的正規流程而產生的訊號(signal)。請描述中 段處理的基本程序。(10%) 5. 針對下列各行程到達與執行時的資訊，若採用SRTF、preemptive priority scheduling 等排班法 (15%) A.畫出每一種排班法的甘特圖。 B.計算每一行程在不同排班法的回復時間與等待時間。 C.計算各排班法的平均等待時間。 行程 到達時間 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.選擇題(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...還真多 @.@ -- http://www.wretch.cc/blog/danielhsieh 抓緊最後能夠放鬆的日子!! --

※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 218.163.152.117 ※ XX9:轉錄至看板 FCUProblems 01/16 20:26