Suppose a file system is based on the indexed allocation str

Suppose a file system is based on the indexed allocation strategy for managing blocks. Assume each file has a directory entry giving the filename, first index block, and the length of the file. The first index block points, in turn, to 249 file blocks and to the next index block. If the file is currently positioned at logical block 2010 and the next operation is to access logical block 308, how many physical blocks must be read from the disk? Explain your answer.

Solution

Index block = 249 file blocks + pointer to the subsequent index block.

Now positioned to logical block 2010,

Next to logical block 308.

2010 – 308 = 1702 blocks.

1702/249= 6.83 = 7 index blocks

308 / 249 = 1.2 = index block 2

2010/249 = 8.07 = index block 9

9-2 = 7 blocks