Erm, I don't understand why its so hard to install multiple operating systems. Even I've done it before, which is pretty bad considering the only reason I was able to install OSX was because I followed a guide. Heck, if I had had any distro of Linux installed, GRUB could've handled all the operating systems--including OSX.
Anyways...
Quote:
| OSX is neither UNIX nor BSD based, it core component is called MACH |
Your "core component" is actually the kernel, which is actually part of BSD. We can go ahead and list every part of BSD, but do you really want to? ~_~