File metadata and inode

摘自《Linux programming by example》(作者：Arnold Robbins)

A partition (physical or logical) that contains file data and metadata, information about files (as opposed to

the file contents, which is information inthe files). Such metadata include file ownership, permissions, size,

and so on, as well as information for use by the operating system in locating file contents.

Inode:

Short for "index node," initially abbreviated "i-node" and now written "inode." A small block of information

describing everything about a file exceptthe file's name(s). The number of inodes, and thus the number of
unique files per filesystem, is set and made permanent when the filesystem is created. 'df -i' can tell you

how many inodes you have and how many are used.

Conceptually, each disk block contains either some number of inodes, or file data. The inode, in turn, contains

pointers to the blocks that contain the file's data.