作者qazwsxee (小尧)
看板Grad-ProbAsk
标题Re: [理工] [OS]-交大98 cpu scheduling
时间Mon Feb 8 19:52:18 2010
※ 引述《chchwy (mat)》之铭言：
: 附一下题目
: http://www2.lib.nctu.edu.tw/n_exam/exam98/cslz/cslz1005.pdf
: 第14题
: 我算一算好像五个选项都对
: 而且距离题目提供的界限65都差很远
: 所以这是出题老师不小心出错还是我解题方有问题...orz ?
Consider 4 CPU bursts with burst lengths P1=4, P2=10, P3=8, and P4=2, all
arriving at the
same time but with an order PI, P2, P3, and then P4. Which one of the
following
process-scheduling algorithm can have a total turnaround time no larger than
65?
(a) First-Come First-Serve
0__4___14____22_____24
4+14+22+24=64
(b) Shortest-Job First
0__2__6___14___24
2+6+14+24=56
(c) Round-Robin with time quantum=8
0__4__12__20__22__24
P1 P2 P3 P4 P2
4+24+20+22=70
(d) Round-Robin with time quantum=4
0__4__8__12__14__18__22__24
P1 P2 P3 P4 P2 P3 P2
4+24+22+14=64
(e) Round-Robin with an infinitely large time quantum
同First-Come First-Serve
是送分的基本题~
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1F：→ crazyjoe:签名档好酷 02/08 19:59
2F：推 chchwy:对吼...看来我想错了 非常感谢 02/08 21:39