BitBake is a simple tool for the execution of tasks. It is derived from Portage, which is the package management system used by the Gentoo Linux distribution. It is most commonly used to build packages, and is used as the basis of the OpenEmbedded project
yapm is a packaging system to automate the generation of Makefiles and rpm.spec files for developers. I will not be working on it again, as i have dumped my redhat distro (and other rpm based distro's) for gentoo