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    Question

    In the context of page replacement algorithms, which

    one minimizes page faults in an ideal scenario?
    A Least Recently Used (LRU) Correct Answer Incorrect Answer
    B First-In-First-Out (FIFO) Correct Answer Incorrect Answer
    C Optimal Page Replacement Correct Answer Incorrect Answer
    D Clock Algorithm Correct Answer Incorrect Answer
    E Second-Chance Algorithm Correct Answer Incorrect Answer

    Solution

    Detailed Explanation: The Optimal Page Replacement Algorithm replaces the page that will not be used for the longest time in the future. It minimizes page faults by making the most informed decision possible based on future knowledge of the reference string. While ideal in theory, it cannot be implemented in practice because predicting future page requests is impossible. However, it is used as a benchmark to evaluate the performance of other page replacement algorithms like LRU and FIFO. This algorithm performs best because it avoids unnecessary page replacements by ensuring only the least critical page is removed. It is particularly useful in environments like simulations or during retrospective analysis of paging behavior. Why Other Options Are Incorrect:

    • Option A: LRU approximates the optimal approach but relies on past behavior, assuming that recently used pages will be reused soon. It does not guarantee minimal faults.
    • Option B: FIFO removes the oldest page in memory, regardless of its future utility. It often causes Belady’s anomaly , where adding more pages increases faults.
    • Option D: The Clock algorithm is an approximation of LRU but is less efficient than the theoretical optimal method.
    • Option E: Second-Chance is a variation of FIFO that considers whether a page has been recently accessed but does not perform as well as Optimal Replacement.

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