- A. File F has 1 MByte of data. How many data blocks, indirect blocks,
second-level indirect blocks, and third-level indirect blocks are used?
**Answer:**Each indirect block holds 1024/4=256 addresses. The inode holds the addresses of (1012-128)/4= 221 data blocks.In a 1 MByte file, there are 1024 data blocks. The first 221 of these are indexed directly by the inode, so there must be ceiling((1024 - 221)/256) = 4 indirect blocks. The first of these is indexed by the inode; the other 3 are indexed by a single doubly-indirect block.

- B. Answer the same question for a file with 100 MBytes of data.
(Note: 1MByte = 2
^{20}bytes. 100 MBytes = 100*2^{20}bytes.)**Answer:**In a 100 MByte file, there are 102,400 data blocks. The first 221 of these are indexed directly by the inode, so there must be ceiling((102400 - 221)/256) = 400 indirect blocks. The first of these is indexed by the inode; the remaining 399 are indexed by two doubly-indirect blocks. The first of these is indexed by the inode, the second is indexed in a single triply-indirect block.