In a Unix-style file system, an index node, informally referred to as an i-node, is a data structure used to represent a filesystem object, which can be one of various things including a file or a directory. Each i-node stores the attributes and disk block location(s) of the filesystem object’s data. Filesystem object attributes may include manipulationmetadata (e.g. creation, access, modify time), as well as owner and permission data (e.g. group-id, user-id, permissions).
A Linux directory lists other filesystem objects by name, normally identifying the listed object by referring to its inode. The directory contains an entry for itself, its parent, and each of its children.