Question

A Unix-style I-node has 10 direct pointers and one single, one double and one triple indirect pointers. Disk block size is 1 Kbyte, disk block address is 32 bits, and 48-bit integers are used.
What is the maximum possible file size?

Answer 1

The number of disk block pointers that will be fit in one block
$=\frac{2^{10}byte}{32bit}=\frac{2^{10}byte}{4byte}$
= 256
Maximum file size due to single indirection pointer
$=256\times 1=256$ KB
Maximum file size due to direct pointer
$=10\times 1=10$KB
Maximum file size due to double indirection pointer
$=256\times 256\times 1KB$
Maximum file size due to triple indirection pointer
$256\times 256\times \times 256\times 1$ KB
So the maximum file size
$=256\times 256\times 256\times 1$ KB
$=2^8\times 2^8\times 2^8\times 2^{10}$ bytes
$2^{24}\times 2^{10}$ bytes
$=2^{34}$ bytes