Linux Filesystem and Links :: Symbolic and Hard links
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Good overview of Linux Links, that's something I hadn't quite gotten too yet:

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Linux has two kinds of filesystem links: symbolic links and hard links.

A symbolic link -- also called a soft link or symlink -- resembles a Windows shortcut. A symlink is a little file that contains the pathname of another object on the filesystem: a file, a directory, a socket, and so on -- possibly even the pathname of another link. This pathname can be absolute or relative.

A hard link isn't itself a file. Instead, it's a directory entry. It points to another file using the file's inode number.
Full article ::

To learn about inodes and the Linux Journaling file systems, read Journaling File Systems, Linux Magazine. Covers ext2, ext3, reiserfs, XFS and JFS.
  • Ext3
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    The Ext3 file system was designed to provide higher availability without impacting the robustness (at least the simplicity and reliability) of Ext2. Ext3 is a minimal extension to Ext2 to add support for journaling. Ext3 uses the same disk layout and data structures as Ext2, and it's forward- and backward-compatible with Ext2.

  • ReiserFS
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    One of the unique advantages of ReiserFS is support for small files -- lots and lots of small files. Reiser's philosophy is simple: small files encourage coding simplicity. Rather than use a database or create your own file caching scheme, use the filesystem to handle lots of small pieces of information.

    ReiserFS is about eight to fifteen times faster than Ext2 at handling files smaller than 1K.

    Even more impressive, (when properly configured) ReiserFS can actually store about 6% more data that Ext2 on the same physical file system. Rather than allocate space in fixed 4K blocks, ReiserFS can allocate the exact space that's needed. A B* tree manages all file system meta-data, and stores and compresses tails, portions of files smaller than a block.

    The new Reiser filesystem, Reiser 4, has better large file support. This is what I'm currently using on Yoper.
  • JFS
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    JFS for Linux is based on IBM's successful JFS file system for OS/2 Warp. Donated to open source in early 2000 and ported to Linux soon after, JFS is well-suited to enterprise environments. JFS uses many advanced techniques to boost performance, provide for very large file systems, and of course, journal changes to the file system.

  • XFS
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    Based on SGI's Irix XFS file system technology, XFS supports meta-data journaling, and extremely large disk farms. How large? A single XFS file system can be 18,000 petabytes (a petabyte is 1024 terabytes, or 2^50 bytes) and a single file can be 9,000 petabytes. XFS is also capable of delivering excellent I/O performance.

    In addition to truly amazing scale and speed, XFS uses many of the same techniques found in JFS.

And there you have it, the Linux file systems explained.
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