Direct block entry
One direct block entry points 1 KB
So 10 direct block entries can point 1 x 10 =10 KB
Single indirect block:
We have 4 bytes address
So number of blocks in indirect block= 1 KB/4 = 256 blocks
– So one indirect block entry can point 256 * 1 KB = 256 KB
Double‐indirect block:
Similarly – 256 * 256 * 1 KB = 64 MB
• Triple Indirect block:
– 256 * 256 * 256 * 1 KB = 16 GB
Total file size = 16 GB + 64 MB+256 KB+ 10 KB ~ 16 GB
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Tip : For competitive exams, speed matters. Maximum file size is mostly depends on triple block entries only and for faster approximate answer we need to calculate triple indirect block only.
256 * 256 * 256 * 1 KB = 16 GB