[理工] 100成大-計組

[bin272max (Ellison)]

Which of the following are true?

(1)Write-allocate policy means when a cache write miss occurs,
the written data are updated in the next level of memory.
(2)There is no cache coherency problem for the write-through cache since the data are written into the next level of memory,
and thus the data are consistent between the two caches.
(3)A cache can be a shared or private.
(4)A cache can use either vitural address ot physical address for its tag.



解答：(3)、(4)

怎麼看都怪怪的...
有高手可以幫我解答嗎@@


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→ ab170926:(1) 先寫到cache在寫到mem
→ ab170926:(2)兩個cache都有同個資料以後其中一個寫入就會不一致
→ ab170926:(3) (4) 本來就有這些類型的cache實作
→ bin272max:(1)我原本查wiki他附了一張圖，說明是跟(1)一樣才覺得奇
→ bin272max:(2)是指memory只跟其中一個cache有寫穿另一則沒嗎?
→ imwind:(2)一個cache有寫穿到mem 但其他cache的值不會改變 不是嗎?
→ BaaaSwin:writethrough只有cache跟memory之間!要再搭配writeupdate
→ BaaaSwin:才會沒有cache coherency problem
→ BaaaSwin:1.應該是No Write-allocate
→ bin272max:明白了！！！感謝：)原來是找克漏字~__~
→ tomchen7947:(1)應改write around 才對
→ tomchen7947:(2)write through僅解決cache和memoyr的問題
→ tomchen7947:要解決cache要用snooping才可
→ bin272max:感謝感謝！！