GATE 2015 CS (CS2) – Question 18
A read takes 50 ns on a cache miss and 5 ns on a hit. Eighty percent of read requests hit. Find the average read time in ns.
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Correct answer: 14
Explanation
The miss and hit times are complete conditional read times. Weight them by their probabilities: 0.8×5+0.2×50=4+10=14 ns. No extra hit lookup time is added to the stated miss time.