Saturday, August 21, 2010

What is an inode?

Index node to refer file in Unix System

An inode is an entry in a disk table that contains information about a file such as its owner, size, and last
access date. The inode is changed when the file is first created and also later if the owner, group, or permissions are changed.

I nodes are objects used to record the information about files

Inode is a structure contains the information necessary for
a process to access a file.Exist in a static form on disk
and the kernel reads them into an in-core inode. 
consists of 
  - file owner identifier
  - file type
  - file access permissions
  - file access times 
  - number of links to the file
  - table of  contents for the disk address of data in   a file
  - file size

in-core copy of the inode contains
  - status of the in-core inode
  - logical device number of file system
  - inode number
  - pointers to other in-core inodes
  - reference count
Inode Contains all the details about a file like owner, 
permission, type....... etc. But it doesn't Contain  
the "Filename" for the paticular file.
inode is basically store information about files and
folders. it is an flat array that store index numbers for
each file.