[理工] [OS]-幾題問題

看板Grad-ProbAsk作者 (梨子)時間16年前 (2010/02/24 22:46), 編輯推噓8(8推 0噓 18→)
留言26則, 8人參與, 最新討論串2/2 (看更多)
1.Which of the following technologies are not designed to overcome the low efficiendy incurred by large page table sizes. (A)limit regester (B)TLB 答案為A，請問TLB為什麼可以? 2.Which of the following statements is false?(台大電機97) (B)System calls are executed with privileged instructions which are not supposed to be use by user programs. (D)In practices,the SJF scheduling algorithm may not be optimal in average waiting time. 3.Which of the schedules results in the minimal average waiting time(over all processes)?(台大電機98) (A)FCFS (B)SJF (C)Nonpreemptive Priority (D)RR -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 140.116.243.66
推
02/24 22:47, , 1F
3.B
02/24 22:47, 1F
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02/24 22:52, , 2F
TLB就是pt的快取，速度比pt快
02/24 22:52, 2F
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02/24 22:53, , 3F
2 D
02/24 22:53, 3F
推
02/24 23:16, , 4F
system call 執行的都是privileged instructions嗎?
02/24 23:16, 4F
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02/24 23:21, , 5F
對
02/24 23:21, 5F
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02/24 23:22, , 6F
行程管理，檔案管理，裝置管哩，資訊維護，通訊，保護
02/24 23:22, 6F
推
02/25 00:04, , 7F
system call 是指要求OS提供服務 OS轉到kernel mode
02/25 00:04, 7F
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02/25 00:05, , 8F
再去執行service function function中通常會用到
02/25 00:05, 8F
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02/25 00:06, , 9F
privileged instruction 但並非全部是privileged inst
02/25 00:06, 9F
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02/25 00:06, , 10F
是這樣說的嗎?
02/25 00:06, 10F
推
02/25 00:11, , 11F
1應該是B，計組版本的解決方法有limit register
02/25 00:11, 11F
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02/25 00:14, , 12F
我覺得所有privilege都透過SYS CALL
02/25 00:14, 12F
推
02/25 00:16, , 13F
2.(B)是false system call是給user call的
02/25 00:16, 13F
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02/25 00:17, , 14F
不可能為priviliged 洪逸洪捷解答書說的
02/25 00:17, 14F
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02/25 00:18, , 15F
但是字面上看起來 我覺得是對的= =
02/25 00:18, 15F
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02/25 00:20, , 16F
我發現我第二題看錯，false的是B
02/25 00:20, 16F
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02/25 00:21, , 17F
不是...是D...又看錯 請忽略上一樓
02/25 00:21, 17F
推
02/25 00:21, , 18F
我怎麼覺得洪逸的翻譯怪怪的阿XD 是不是解讀錯了?
02/25 00:21, 18F
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02/25 00:22, , 19F
信洪逸的話......就....
02/25 00:22, 19F
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02/25 00:22, , 20F
第2題是單選嗎?
02/25 00:22, 20F
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02/25 00:23, , 21F
我覺得B對阿
02/25 00:23, 21F
推
02/25 00:44, , 22F
我也覺得b對耶…
02/25 00:44, 22F
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02/25 12:00, , 23F
第一題他問的是可以改善SIZE大小 TLB 怎麼改善的...?
02/25 12:00, 23F
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02/25 12:01, , 24F
第二題D對的話又跟第三題矛盾... 可是又覺得B怪怪的QQ
02/25 12:01, 24F
推
02/26 01:00, , 25F
第一題的意思叫做"PageTable太大造成的「效率」低落"
02/26 01:00, 25F
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02/26 01:00, , 26F
解法就是造個TLB來當page table的cache 這是TLB存在的意義啊
02/26 01:00, 26F
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