作者luckyburgess (心安即自在)
看板Grad-ProbAsk
标题[理工] [计组]-memory
时间Wed Feb 10 23:53:02 2010
想请问下面这题 :
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?
手边的答案为 :
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
想请问它这样解对吗?? 对这种题目好头痛orz
麻烦高手解答一下 感谢!!
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1F：推 polomoss:这种题目好像都是OS的，比较难算 02/10 23:56
2F：推 lovefo:我也对OS的计算page tables 很头痛 尤其是2-level的 02/10 23:59
3F：推 polomoss:每次算的答案都不同~解答也不同XD 02/11 00:04
4F：推 EntHeEnd:他有加3bit 是 valid dirty 和 ref bit 吗 ? 02/11 00:17
5F：推 taitin:恩 02/11 00:24
6F：推 gorocky:真的!!有同感......跟楼楼上那一位 02/11 00:25
7F：推 EntHeEnd:喔喔 02/11 01:06
8F：推 EntHeEnd:其实我觉得他level 1 放那3bit怪怪的 顶多放valid就好... 02/11 01:37
9F：→ EntHeEnd:level 2 再放那3bit比较合理... @@... 02/11 01:37