libburnia is a project comprised of libraries and binaries for reading, mastering, and writing optical discs. It provides libburn, a CD/DVD/BD burn library, libisofs, a manipulation library for ISO 9660 filesystems, and libisoburn, a ISO 9660 multi-session library. On top of them there is cdrskin, a cdrecord emulator, and xorriso, a all-in-one application for ISO 9660 multi-session operations which additionaly provides a limited emulation of mkisofs.
Dar is a shell command that makes backup of a directory tree and files. Its features include splitting archives over several files, DVD, CD, ZIP, or floppies, compression, full or differential backups, strong encryption, proper saving and restoration of hard links, extended attributes, file forks, Door inodes, and sparse files, remote backup using pipes and external commands (such as ssh), and rearrangement of the "slices" of an existing archive. It can run commands between slices, before and after saving some defined files or directories (for a proper database backup, for example), and quickly retrieve individual files from differential and full backups. Several external GUIs exist as alternatives to its CLI interface, like kdar, DarGUI, SaraB, etc.
LRZIP is a compression program and library that can achieve very high compression ratios and speed when used with large files using unlimited sized compression windows. It uses the combined compression algorithms of zpaq and lzma for maximum compression, lzo for maximum speed, and the long range redundancy reduction of rzip. It is designed to scale with increases with RAM size, improving compression further. A choice of either size or speed optimizations allows for either better compression than even lzma can provide, or better speed than gzip, but with bzip2 sized compression levels. It also has high grade password protected encryption and full STDIN/STDOUT support.
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).