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).
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.
mmounter tries to mimic the behaviour of MacOS with regards to automatic monitoring and mounting of the volumes in your system (CDs, ZIP disks, floppies, HDs) using their volume name as the mount point. It will optionally eject devices and let users mount/umount them. Currently mmounter supports ext2, ext3, iso9660 (CD), HFS, and VFAT. This tool is user-space only (doesn't require any kernel patching) and should be fairly portable.
muser lists processes which have a given directory (or cwd if not specified) as a parent of their current working directory (thus making it impossible to unmount that directory if it is a mount point). This script has overlapping functionality with the fuser program from the psmisc package, but has the advantage that it works on SMB mounts. Additionally, it provides a color, formatted listing of process IDs, executable names, current working directories, and the command lines used to run the programs. It works with varying-sized /proc/*/cwd fields.
Partition Image is a Linux/UNIX utility similar to Symantec's Ghost. This uility saves partitions in the EXT2, Reiserfs, NTFS, HPFS, FAT16, and FAT32 file system formats to an image file. The image file can be compressed with gzip or bzip2 in order to save disk space, and it can be split in order to fit onto a series of floppy disks. This program can be useful for backup purposes. A boot/root disk is also provided, allowing you to run Partition Image without Linux installed on the hard disk.
Unison is a file-synchronization tool for Unix and Windows. It allows two copies of a collection of files and directories to be stored on different hosts (or different disks on the same host), modified separately, and then brought up to date by propagating the changes in each replica to the other. Unison can deal with updates to both replicas of a distributed directory structure. Updates that do not conflict are propagated automatically. Conflicting updates are detected and displayed. Unison can communicate through a direct socket link or through an rsh/ssh tunnel. It uses network bandwidth efficiently.
scponly is an alternative "shell" of sorts for system administrators who would like to provide access to remote users to both read and write local files without providing any remote execution priviledges. Functionally, it is a wrapper around the ssh suite of applications. It is typically used by creating a user whose shell is set to scponly. This user can neither login interactively nor execute commands remotely, but it can use scp and sftp to download and upload files to the computer, governed by the usual Unix file permissions.