Afio makes cpio-format archives. It deals somewhat gracefully with input data corruption, supports multi-volume archives during interactive operation, and can make compressed archives that are much safer than compressed tar or cpio archives. Afio is best used as an `archive engine' in a backup script.
bzip2 is a portable, lossless data compressor based on the Burrows-Wheeler transform. It achieves good compression and runs on practically every (32/64-bit) platform in the known universe. The compression engine is also available as a library (libbz2), should you desire a programmatic interface.
The dump package contains both dump and restore. Dump examines files in a filesystem, determines which ones need to be backed up, and copies those files to a specified disk, tape or other storage medium. The restore command performs the inverse function of dump; it can restore a full backup of a filesystem. Subsequent incremental backups can then be layered on top of the full backup. Single files and directory subtrees may also be restored from full or partial backups.
fistgen is the FiST language code generator, used to create stackable file systems out of templates and a high-level language. This package comes with stackable file system templates for Linux, Solaris, and FreeBSD. It also contains several sample file systems built using the FiST language: an encryption file system, a compression file system, and more - all of which are written as portable stackable file systems.