作者luckyburgess (心安即自在)
看板Grad-ProbAsk
標題[理工] [計組]-memory
時間Wed Feb 10 23:53:02 2010
想請問下面這題 :
Consider a logical-address of 2048 words each,mapped onto a physical
memory of 64 frames. Please answer the following questions assuming
that the smallest memory allocation unit is one byte
(c)Assuning a 2-level page table is used and the first-level table
has 32 entries, what is the minimal amount of memory (in bytes)
required by the page tables?
手邊的答案為 :
level-1 : 2^5*(3+6(for L2))= 32*9 bit= 36 bytes
level-2 : 2^6*(3+6(for physical address))
= 64*9 bit= 72 bytes
total= 36 bytes + 72 bytes = 108 bytes
想請問它這樣解對嗎?? 對這種題目好頭痛orz
麻煩高手解答一下 感謝!!
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推 polomoss:這種題目好像都是OS的，比較難算 02/10 23:56
推 lovefo:我也對OS的計算page tables 很頭痛 尤其是2-level的 02/10 23:59
推 polomoss:每次算的答案都不同~解答也不同XD 02/11 00:04
推 EntHeEnd:他有加3bit 是 valid dirty 和 ref bit 嗎 ? 02/11 00:17
推 taitin:恩 02/11 00:24
推 gorocky:真的!!有同感......跟樓樓上那一位 02/11 00:25
推 EntHeEnd:喔喔 02/11 01:06
推 EntHeEnd:其實我覺得他level 1 放那3bit怪怪的 頂多放valid就好... 02/11 01:37
→ EntHeEnd:level 2 再放那3bit比較合理... @@... 02/11 01:37