※ 引述《loeooo (篮球狂)》之铭言： : A page-replacement algo. minimizes the number of page faults by distributing : heavily used pages evenly over all of memory. It associates with each : page frame a counter of the number of pages that are associated with that : frame, and the initial value of the coounters is 0. Then, to replace a page, : it searches for the page frame with the smallest counter. The counters are : increased whenver a new page is associated with that frame; and are decreased : whenever one of the pages associated with that frame is no longer required. : a) How many page faults occur for the algo. for the following reference string, : for four page frames? : 1,2,3,4,5,3,4,1,6,7,8,7,8,9,7,8,9,5,4,5,4,2. : 这题在说什麽啊? 不太懂意思?? 可以顺便解个我看吗? 解前几个大概告诉我做法就好了 : 谢谢!! 这题大致上讲说,使用LRU的策略~ 题目前半段大致上在讲LRU用counter的作法 1 2 3 4 5 3 4 1 6 7 8 7 8 9 7 8 9 5 4 5 4 2 ___________________________________________ 1 1 1 1 5 5 6 6 6 6 5 5 5 2 2 2 2 1 1 1 1 9 9 9 9 3 3 3 3 3 7 7 7 7 4 4 4 4 4 4 4 8 8 8 8 2 共13次的page faults : b) what's the minimum number of page faults for an optimal page replacement : strategy for the reference string in part (a) with four page frames? : 这题是用最佳策略法吗? 我算出来11次 不知道跟大家算的一不一样耶?? 1 2 3 4 5 3 4 1 6 7 8 7 8 9 7 8 9 5 4 5 4 2 ___________________________________________ 1 1 1 1 1 6 7 7 7 4 2 2 2 2 5 5 5 5 5 5 5 3 3 3 3 3 8 8 8 8 4 4 4 4 4 9 9 9 共11次page faults --

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