PackDir is a high performance directory archiver.

Features :

    Packs a directory tree (i.e. all directories and files it contains) into a single archive file (very similar to a Zip file).
    Can (obvious one this ...) perform the reverse process, i.e. recreate the original directory from the archive file.
    Optionally compresses file data with the widely used LZW algorithm.
    Is heavily optimized for speed (and is several times faster than most other archiving utilities) and is therefore ideal for regular archiving tasks, e.g. backups. 

Note that archives produced by PackDir can also be read from (but not written to) by the excellent (commercial) SparkFS archiving utility.