Superblock

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Rough structure of the Unix file system

The superblock is part of various file systems of the Unix operating system and its derivatives . It typically contains the following file system management information:

  • File system size
  • Number of free blocks
  • Pointer to the list of free blocks
  • Pointer to the first free block in the list of free blocks
  • Size of the inode list
  • Number of free inodes
  • Pointer to the list of free inodes
  • Pointer to the next free inode in the list of free inodes
  • Lock fields for the list of free blocks / inodes (e.g. for defective blocks)
  • Display field whether superblock has been changed

The file systems that have a superblock include the Unix file system , the Minix file system, and the extended file systems ext2 , ext3 and ext4 .

Not all file systems contain all of these fields, for example ZFS does not use a fixed number of inodes .

literature

  • F. Schweiggert, A. Borchert, M. Grabert and J. Mayer: Accompanying script for the lecture General Computer Science III. Ulm, 2004