inode, inode table and map

[Shahul]

Hi all

I know that inode will have the details about the file or directory, like size, date stamp, location..etc. What about inode table? What exactly it contains? What for map is used? I hope someone will clarify me.

Thanks and regards
Shahul

[Steve Steel]

Hi

inode table:

Table at the start of a filesystem that contains pointers to the data on the hard disk.

inode

see
http://www.docs.hp.com/cgi-bin/fsearch/framedisplay?top=/hpux/onlinedocs/B2355-90682/B2355-90682_top.html&con=/hpux/onlinedocs/B2355-90682/00/02/289-con.html&toc=/hpux/onlinedocs/B2355-90682/00/02/289-toc.html&searchterms=map%7cinode&queryid=20030729-024445



To monitor the tables use sar


Steve Steel

[Radhakrishnan Venkatara]

The inode table is simply an "inode cache". Its an in-core copy of the inodes from the file system on disk. For efficiency reasons, the most recent open inodes is kept in main memory.


radhakrishnan

[Bill Hassell]

inodes are pointers to occupied space in the filesystem. The kernel's inode cache keeps a copy of current and recently opened inodes (files) in memory to speed up access to popular files. The inode table is just the name given to the directory structure. inodes point to space and contain informtaion about timestamps, ownership, etc but most importantly: NOT the filename. While a single inode can point to space occupied by a file, the inode has no name. That's what the directory does. It is a list of names and inode numbers. This is how links work. Two or more names can point to the same inode (or inode chain if the file is larger than a single inode).

For example, there is only ONE lvm command! Do this:

ll -i /sbin | sort

Then look for any of the LVM comands like vgcreate or lvextend. You'll see that there are 30+ links to the same inode (one executable).

Map is an ambiguous word in this context. The inode map might refer to the collection of inodes that are active, or it might refer to the directory that maps inodes to filenames (and directories are actually files too).