* The super-block owes its name to its historical heritage, from when the first data block of a disk or partition was used to hold meta-information about the partition itself. The super-block is now detached from the concept of data block, but still is the data structure that holds information about each mounted file-system. The actual data structure in Linux is called struct super_block and hosts various housekeeping information, like mount flags, mount time and device blocksize. The 2.0 kernel keeps a static array of such structures to handle up to 64 mounted file-systems. 

  

 * An inode is associated to each file. Such an 'index node' encloses all the information about a named file except its name and its actual data. The owner, group, permissions and access times for a file are stored in its inode, as well as the size of the data it holds, the number of links and other information. The idea of detaching file information from filename and data is what allows to implement hard-links -- and to use the `dot' and `dot-dot' notations for directories without any need to treat them specially. An inode is described in the kernel by a struct inode. 

  

  

 * The file itself is something that is associated to an inode. Usually files are data areas, but they can also be directories, devices, FIFO's or sockets. An 'open file' is described in the Linux kernel by a struct file item; the structure encloses a pointer to the inode representing the file. file structures are created by system calls like open, pipe and socket, and are shared by father and child across fork. 

  

 File system that use inodes: