[理工] [OS] File system

[zelkova (祥)]

1. Which statements are false?
   (A)index allocation has better performance than linked allocation.
   (B)index allocation has poor performance than linked allocation.

   Ans:(A)(B)are the same performance problem
   請問index不是比較快嗎?


2. Storage can be dynamically allocated to the hosts attached to the same
   storage-area network.

   請問這句話錯在哪裡呢?


3. 這題題目很長.. 先提一下疑問@@.. 解答在求page table的entry用了 32+4 bits
   從算式來看, 解答把offset(14bits)也存進page table惹...
   不過entry裡面應該不用存offset吧? 這樣是不是 18+4 bits就OK了捏?

   Consider a virtual memory system with the following properties:
   38-bit virtual byte address. 16-KB pages, and 32-bit physical byte address.
   What is the total size of the page table for each process on this machine,
   assuming that the valid. Protection, dirty, and use bits take a total of 4
   bits and the all the virtual pages are in use? (Assume that disk address are
   not stored in the page table)


4. http://www2.lib.nctu.edu.tw/n_exam/exam92/cis/cis136.pdf

   12題答案是(A).. 請問怎麼解答的呢?

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◆ From: 220.135.91.184
※ 編輯: zelkova         來自: 220.135.91.184       (01/31 04:34)
推 aoqq12:....空間分配跟執行速度應該沒什麼關係
→ aoqq12:跟seek time比較有關係
推 aoqq12:第三題 嗯它寫錯了沒錯 2^24(4+18)bit
→ zelkova:謝謝一樓戴眼鏡的同學~  ...Q2跟Q4請大家幫幫忙@@
→ aerystyle:Q4 因為沒有互次存取所以會有race condition的問題
→ aerystyle:因為主要為C.D的值在改變，所以只需討論他們的執行順序
→ aerystyle:1.(80.80)C:先T1再T2，D:T2先assignT1再assign
→ aerystyle:2.(120.80)C:T2先assignT1再assignD:T2先assignT1再assi
→ aerystyle:gn，其他的就差不多的做法，有問題在站內信問我吧