There is some debate about how this is supposed to work. I have, I think, confirmed that having the startup executable verify that it is supposed to run in /etc/hostconfig is what’s supposed to happen.
But now I’m hearing that there are two StartupItems directories: /System/Library/StartupItems, reserved for factory-installed stuff, and /Library/StartupItems for site-specific stuff (why not /Local/Library/StartupItems?).
Darwin machines only have the first directory. I gather most people are running the full OS X installation.
It seems to me Apple needs some help sorting all this out: I need a job of some kind. Hmm, perhaps some of the Apple employees who keep dropping by could look over my resume (down on your right).
<another clarification from Creed Erickson on the missing /Library/StartupItems directory>
Create it.
Well, if I am going to create it, I would just as soon call it /Local/Library/StartupItems.
This could be documented a little better, as could the stuff about /etc/hostconfig, without which none of the rest of this matters.