Linux, in the tradition of UNIX-like operating systems, implements file system permissions using a rather coarse scheme. While this is sufficient for a surprisingly large set of applications, it is too inflexible for many other scenarios. For that reason, all the major commercial UNIX operating systems have extended this simple scheme in one way or the other. This is an effort to implement POSIX-like Access Control Lists for Linux. Access Control Lists are built on top of Extended Attributes, which can also be used to associate other pieces of information with files such as Filesystem Capabilities, or user data like mime type and search keywords.
Plash is a sandbox for running GNU/Linux programs with minimum privileges. It is suitable for running both command line and GUI programs. It can dynamically grant Gtk-based GUI applications access rights to individual files that you want to open or edit. This happens transparently through the Open/Save file chooser dialog box, by replacing GtkFileChooserDialog. Plash virtualizes the file namespace and provides per-process/per-sandbox namespaces. It can grant processes read-only or read-write access to specific files and directories, mapped at any point in the filesystem namespace. It does not require modifications to the Linux kernel.
Chiron FS is a FUSE based filesystem that implements replication at the filesystem level like RAID 1 does at the device level. The replicated filesystem may be of any kind you want; the only requisite is that you mount it. There is no need for special configuration files; the setup is as simple as one mount command (or one line in fstab).
makebootfat is a tool to make bootable USB disks. It can autodetect, partition, format, and populate the USB disk in a single step without any user interaction. It can also create disk images which are simultaneously compatible with all the three USB booting standards: USB-FDD, USB-HDD, and USB-ZIP.
ClusterNFS is a set of patches for the "Universal NFS Daemon" (UNFSD) to allow multiple clients to nfs mount the same root filesystem by providing "tagged" filenames. When a client requests the file "/path/filename", the ClusterNFS server checks for the existence of files of the form "/path/filename$$TAG=value$$". If such a file exists and the client has a matching value for KEY, this file is returned. If the client does not have a matching value or no such file exists, the file request proceeds as normal. Currently supported keys include HOST (hostname), IP (IP number), CLIENT (matches any nfs client) and CREATE (for "tagged" creation of files).