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Assignment6

# Assignment6 - nanoseconds Problem 2 Consider the...

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Department of Computer Science University of Minnesota, Twin Cities CSci 5103 - Operating Systems -- Fall 2010 (Instructor: Tripathi) Assignment 6 Due Date: November 14 (No late assignment would be accepted after November 16 because solutions would be posted on November 17.) Problem 1: (a) Assume that we have a paged memory, which is being used in “real mode” (i.e. without virtual memory). The page table is stored in the main memory. The memory access time is 100 nano seconds. This system uses a TLB, which takes 20 nano seconds for searching. It was found to have hit rate of 90%. What is the effective memory access time for this system? (b) Now suppose that this is demand paged virtual memory system. It takes 5 milliseconds to service a page fault if an empty frame is available or if the replaced page is not modified, and 10 milliseconds if the replaced page is modified. Assume that the page to be replaced is modified 80% of the time. What is the maximum acceptable page-fault rate for an effective access time of no more than 200

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Unformatted text preview: nanoseconds? Problem 2: Consider the two-dimensional array A: int A = new int [100][100]; where A[0][0] is at location 200, in a paged system with pages of size 200. A small process is in page 0 (locations 0 to 199) for manipulating the matrix; thus, every instruction fetch will be from page 0. For three page frames, how many page faults are generated by the following array-initialization loops, using LRU replacement, and assuming page frame 1 has the process in it, and the other two are initially empty: a. for (int j = 0; j < 100; j++) for (int i = 0; i < 100; i++) A[i][j] = 0; b. for (int i = 0; i < 100; i++) for (int j = 0; j < 100; j++) A[i][j] = 0; Problem 3 : C hapter 3, Problem 10 Problem 4 : C hapter 3, Problem 24 Suppose that a page-fault occurs after the 8 th clock tick. Which frame will be selected to bring the new page in memory? Problem 5 : C hapter 3, Problem 25 Problem 5 : C hapter 3, Problem 26 Problem 6 : C hapter 3, Problem 28...
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Assignment6 - nanoseconds Problem 2 Consider the...

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