movemetafs is a searchable filesystem metadata store for Linux that lets users tag local files (including image, video, audio, and text files) by simply moving the files to a special folder using any file manager. It also lets users find files by tags using a boolean search query. The original files (and their names) are kept intact. movemetafs doesn't have its own user interface, but it is usable with any file manager.
rfsdelta is a kernel module for the Linux 2.6 series that collects all filesystem inode changes (recursively) and reports them to a userspace process. It is similar to inotify, dnotify (but provides recursive notification, and only a single watcher process is allowed), fschange, fsevent, and rlocate (but also reports unlink(), rmdir(), and st_*). rfsdelta was based on the kernel module shipped with rlocate 0.5.5.
xlike is a patch collection for the Linux vanilla kernel. It includes as many stable enhancements for the Linux kernel as possible. These include code from Xen, Kernel Mode Linux, Rule Set Based Access Control, Novell AppArmor, Openswan, grsecurity, Linux VServer, Linux-PHC, web100, Nefilters, Suspend2, Speakup, SquashFS, UnionFS, Bootsplash, BadRAM, and more. It also contains many drivers and fixes.
MT-write is a binary patch for multi-threaded writing. It comes in the form of a shared object that can be preloaded to programs like tar to make their write operations multi-threaded. Multi-threaded writing can improve performance on RAM based filesystems and highly scalable filesystems with multiple spindles.
NTFS-3G is a stable read/write NTFS driver. It is available for over 180 Linux distributions and the default read/write NTFS driver for most major ones. It has been ported to many other operating systems like FreeBSD, NetBSD, Solaris, Haiku, and Mac OS X, and to little/big-endian, 32/64-bit, and MMU-less computer architectures.
Earth allows you to find files across a large network of machines and track disk usage in real time. It consists of a daemon that indexes filesystems in real time and reports all the changes back to a central database. This can then be queried through a simple Web interface. Think of it like Spotlight or Beagle, but operating system-independent with a central database for multiple machines. Earth is initially focused on managing the explosion of data that occurs in digital visual effects work.