fuselagefs consists of a C++ wrapper class for FUSE called Fuselagefs, as well as Delegatefs, which is a Fuselagefs subclass that delegates all operations to an underlying base filesystem. With Delegatefs, you can expose dir1 at mountpoint dir2 very easily as a FUSE filesystem. Subclasses of Delegatefs can then be created, which add a little extra functionality to the delegation operation but rely on the parent class to perform the work and return errors to FUSE in an appropriate manner. An example subclass is petardfs.
petardfs is a FUSE filesystem designed to hoist your applications with errors. With no configuration, petardfs takes a base filesystem and exposes it through FUSE. An XML configuration file is used to tell petardfs which files to report errors for and what error code to use. For example, foo.txt can have an EIO error at bytes 34 to 37. There is explicit support for errors such as EAGAIN and EINTR, where petardfs will only report such transient errors a nominated number of times. This is handy for testing applications that support such I/O conditions gracefully.
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.
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.
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.