I installed the latest Debian 7.5 image (dated 2014-05-14) onto my BeagleBone Black, and have hit a brick wall trying to figure out why things I just did on a Raspberry Pi running Raspbian do not work on this version of Debian. One of those things is trying to get an init.d script to run on startup – specifically /etc/init.d/hwclock.sh.
I am now suspecting that this version of Debian has switched to using systemd. Would someone please confirm (or deny) my suspicion?
systemctl will show you all the details. Most of the gory details live under
/lib/systemd/system
These two links are great starting points. I'm still trying to wrap my brain around the whole systemd concept. I will say that it does boot every piece of hardware I've used it on very fast.