changedfiles is a framework for filesystem replication, security monitoring, and/or automatic file transformations--essentially any application where you'd poll files or directories and either do something to them or send them somewhere else (or both). The difference is that the kernel tells you when they change instead of you having to poll. It's an easy real time FTP push mirror to one or multiple sites. It's also a full fledged MySQL client, so you can do realtime database operations (for example, batch imports). It consists of two parts: a kernel module (works with Linux kernel version 2.4) which reports to a device whenever a file on the filesystem changes, and a daemon which runs in user space and can be configured to do almost any action when a change to a file matching the one of the patterns it looks for is reported. The kernel module is SMP safe and has been tested on Intel, PowerPC, and Alpha.
VDMFEC implements Block ECC using a Forward Error Correction (FEC) code based on Vandermonde (VDM) matrices in GF(2^8) due to Luigi Rizzo. Given the FEC parameters K and N, with N greater than K, N blocks are written for every K input blocks in such a way that any K blocks are sufficient to reconstruct the data. That is, up to N - K blocks out of every group of N blocks may be lost without loss of data. VDMFEC's primary application is intended to be in recovering data from unreliable media such as diskettes. With appropriate parameters, files may be recovered even with many read errors. (Note that you must write the data to the diskette using this program in order to be able to recover the data later!)
The GNotary client is a multi-platform GUI client that allows you to select files via drag and drop from any file manager, create the secure hash sums for each file, and submit the hash list to a list of digital notary servers. Optionally, all selected files can be backed up into a zip archive. It is written in Python and requires the wxPython toolkit.
backup2l is a command line tool for generating, maintaining, and restoring backups on a mountable file system. The main design goals are low maintenance effort, efficiency, transparency, and robustness. In a default installation, backups are created autonomously by a cron script. It supports hierarchical differential backups with a user- specified number of levels and backups per level.