Each file is represented by a structure, called an inode. Each inode
contains the description of the file: file type, access rights, owners,
timestamps,
size, pointers to data blocks. The addresses of data blocks allocated to
a file are stored in its inode. When a user requests an I/O operation on
the file, the kernel code converts the current offset to a block number,
uses this number as an index in the block addresses table and reads or writes
the physical block. Figure 
represents the structure of an
inode.
ext2fs/inode 8cm 8cm Structure of an inode