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Inode Table

Inode Table

The Inode table is stored in the disk and has an entry for each file present in the disk. It consists of MAX_FILE_ NUM (60) entries.

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Each entry of Inode Table is of 16 words.

  • FILE TYPE (1 word) - specifies the type of the given file (DATA, EXEC or ROOT). More information about file types is given here.
  • FILE NAME (1 word) - Name of the file
  • FILE SIZE (1 word) - Size of the file. Maximum size for File = MAX_FILE_SIZE = 2048 words
  • USER ID (1 word) - User Id of the owner of the file.
  • PERMISSION (1 word) - Permission of the file; it can be OPEN_ACCESS or EXCLUSIVE.
  • Unused (3 words)
  • DATA BLOCK 1 to 4 (4 words) - each DATA BLOCK column stores the block number of a data block of the file. If a file does not use a particular DATA BLOCK , it is set to -1.
  • Unused (4 words)

An unused entry is indicated by -1 in the FILE NAME field

A free inode entry is denoted by -1 in FILENAME field

Important

On fdisk command of XFS Interface , inode table entry of root is initialised to FILE_TYPE=1, FILE_SIZE=512, DATA_BLOCK=5

Memory copy of the Inode table is present in 59 of the memory

eXpOS requires that the index of the inode table entry of a file and the index of its root file entry must match.

3 and 4 in the block list