UGC-NET | UGC NET CS 2015 Dec – II | Question 49

A unix file system has 1-KB blocks and 4-byte disk addresses. What is the maximum file size if i-nodes contain 10 direct entries and one single, double and triple indirect entry each?
(A) 32 GB
(B) 64 GB
(C) 16 GB
(D) 1 GB

Answer: (C)
Explanation: One direct block address(DBA) points 1 kB and we have 10 DBA. So it will take 10 kb. Address will take 4 bytes.
# of blocks in indirect block = 1kB / 4 b = 1024 / 4 = 256 blocks.
Single direct block take 256 * 1 kB = 256 KB.
Double indirect block will take 256 * 256 = 2¹⁶ kB = 64 MB.
Triple direct block will take 256 * 64 MB = 2¹⁴ MB = 16 GB.
So, option (C) is correct.
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