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GATE 2014 CS (CS2) – Question 19

Computer Organization and Architecture · Memory Interfacing and Hierarchy · 1 mark · Numerical answer

A 4-way set-associative cache has capacity 16 KB and blocks of 8 words. Words are 32 bits and physical address space is 4 GB. Find TAG-field width (bits).

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Correct answer: 20 to 20

Explanation

A block contains8×4=32bytes, needing5offset bits. The16KBcache has512blocks and128sets at4ways, needing7index bits. A4GBbyte-addressed memory uses32address bits, leaving32−5−7=**20tag bits**.