What is an inode?
An inode (index node) is a data structure used in UNIX-like systems to store information about files and directories.
Key Points
- Data Structure: An inode stores attributes of files and directories.
- Attributes: Includes information like file ownership, modification date, file size, and access permissions.
- UNIX Systems: Primarily used in UNIX-like operating systems.
Detailed Explanation
- Basic Concept: An inode contains metadata about a file or directory. It does not store the actual data of the file, but rather information about it.
- Components Stored in an Inode:
- File Owner: Who owns the file.
- Modification Date: When the file was last updated.
- File Size: How large the file is.
- Access Rights: Permissions related to who can read or write the file.
- Data Location: Information on where the actual file data is stored on the disk.
- Example: If a file named
example.txt
is created in a directory, its content and its inode are stored separately:- The actual content of
example.txt
is saved in a data block. - The inode stores the attributes of
example.txt
and points to where the file content is located.
- The actual content of
- File Access Flow:
- To access
example.txt
, the system looks up the directory to find the inode number associated withexample.txt
. - The inode is then used to retrieve the file’s attributes and the location of the file’s data.
- To access
- Identification: Each inode is assigned a unique number, known as the inode number, which helps in identifying it.
Summary: An inode is a data structure that holds metadata about files and directories in UNIX-like systems. It includes information such as file attributes and the location of the file data.