GNU grep is based on a fast lazy-state deterministic matcher (about twice as fast as stock Unix egrep) hybridized with a Boyer-Moore-Gosper search for a fixed string that eliminates impossible text from being considered by the full regexp matcher without necessarily having to look at every character. The result is typically many times faster than Unix grep or egrep.
KBACKUP is intended for handling of backups no matter whether they reside on disk or tape or even in files. As most other backup programs available today are either confusing the user with lots of long command line options, or user friendly but not powerful at all, the aim behind writing KBACKUP was to provide a user friendly yet powerful backup program. It is also intended to be kept compatible to existing and well proven archive formats, so you can restore your archives even if you should not have KBACKUP around anymore.