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Consider a paging system with

[问答题]
Consider a paging system with the page table stored in memory.
a. If a memory reference takes 200 nanoseconds, how long does a paged memory reference take?
b. If we add associative registers, and 75 percent of all page-table references are found in the associative registers, what is the effecttive memory reference time? (Assume that finding a page-table entry in the associative registers takes zero time, if the entry is there.)

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a. 400 nanoseconds; 200 nanoseconds to access the page table and 200 nanoseconds to access the word in memory.
b. Effective access time = 0.75 x (200 nanoseconds) + 0.25 x (400 nanoseconds) = 250 nanoseconds.
发表于 2018-03-23 21:56:44 回复(0)