Q. In a two-level virtual memory, x = 10−7s and y =10−2s. What must be the hit…
Q. In a two-level virtual memory, x = 10−7s and y =10−2s. What must be the hit ratio H be in order for the access efficiency to be at least 90 percent of its maximum possible value ____________ . (Round off to two decimal places)
Answer: 0.99 — Key definitions: let x be the access time on a hit and y be the access time on a miss. Step 1: Average access time A = H·x + (1 − H)·y. Step 2: Define access…
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Correct answer: 0.99
Key definitions: let x be the access time on a hit and y be the access time on a miss.
Step 1: Average access time A = H·x + (1 − H)·y.
Step 2: Define access efficiency as the fraction of improvement relative to the worst-case (miss) time: Efficiency = (y − A) / (y − x).
Step 3: Substitute A and simplify:
Efficiency = (y − (H·x + (1 − H)·y)) / (y − x) = (H·(y − x)) / (y − x) = H.
Step 4: Require efficiency ≥ 0.90, therefore H ≥ 0.90.
Final answer: The hit ratio must be at least 0.90 (rounded to two decimal places).
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