作者qazwsxee (小堯)
看板Grad-ProbAsk
標題Re: [理工] [OS]-交大98 cpu scheduling
時間Mon Feb 8 19:52:18 2010
※ 引述《chchwy (mat)》之銘言:
: 附一下題目
: http://www2.lib.nctu.edu.tw/n_exam/exam98/cslz/cslz1005.pdf
: 第14題
: 我算一算好像五個選項都對
: 而且距離題目提供的界限65都差很遠
: 所以這是出題老師不小心出錯還是我解題方有問題...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
是送分的基本題~
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→ crazyjoe:簽名檔好酷 02/08 19:59
推 chchwy:對吼...看來我想錯了 非常感謝 02/08 21:39