How we can map inode to block the data of a file

Question

How we can map ‘inode’ to block the data of a file?

Answer 1

Inode has thirteen block addresses. The primary ten are direct block addresses of the primary ten data blocks in the file. The eleven address points to a one-level index block. The twelve address points to a two-level (or double in-direction) index block. The thirteen address points to a three-level (or triple in-direction) index block. This offers an extremely large maximum file size with efficient access to big files, however also small files are accessed directly in one disk read.