Describe Inodes in files systems
An index-node (inode) is a data structure on a traditional Unix-style file system such as UFS and is identified by an integer number, often referred to as an i-number or inode number.An inode stores all the information about a regular file [called as metadata such as file ownership,access mode(read write and execute) and file type etc]directory, or other file system object, except its data and name.
The inode number indexes a table of inodes in a known location on the device; from the inode number, the file system driver portion of the kernel can access the contents of the inode, including the location of the file allowing access to the file.
On many types of file system implementations, the maximum number of inodes is fixed at file system creation, limiting the maximum number of files the file system can hold. A typical allocation heuristic for inodes in a file system is one percent of total size.
Some of attributes of files that can be found from inode are
Useful Links:--
http://en.wikipedia.org/wiki/Inode
An index-node (inode) is a data structure on a traditional Unix-style file system such as UFS and is identified by an integer number, often referred to as an i-number or inode number.An inode stores all the information about a regular file [called as metadata such as file ownership,access mode(read write and execute) and file type etc]directory, or other file system object, except its data and name.
The inode number indexes a table of inodes in a known location on the device; from the inode number, the file system driver portion of the kernel can access the contents of the inode, including the location of the file allowing access to the file.
On many types of file system implementations, the maximum number of inodes is fixed at file system creation, limiting the maximum number of files the file system can hold. A typical allocation heuristic for inodes in a file system is one percent of total size.
Some of attributes of files that can be found from inode are
- The size of the file in bytes.
- Device ID (this identifies the device containing the file).
- The User ID of the file's owner.
- The Group ID of the file.
- The file mode which determines the file type and how the file's owner, its group, and others can access the file.
- Additional system and user flags to further protect the file (limit its use and modification).
- Timestamps telling when the inode itself was last modified (ctime, inode change time), the file content last modified (mtime, modification time), and last accessed (atime, access time).
- A link count telling how many hard links point to the inode.
- Pointers to the disk blocks that store the file's contents (see inode pointer structure).
Useful Links:--
http://en.wikipedia.org/wiki/Inode
An index-node (inode) is a data structure on a traditional Unix-style file system such as UFS. An inode stores all the information about a regular file, directory, or other file system object such as file ownership, access mode (read, write, execute permissions), and file type EXCEPT its data and name.
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