Posix vs. Windows

[Mehrdad]

From looking at Phobos, I'm understanding that the main 
difference between the implementation of various features for 
Posix systems as compared to Windows systems (aside from the API, 
etc.) is that Windows tends to do a lot of stuff *before* the 
program is loaded (and hence requires special cases in a lot of 
places), whereas Posix systems tend to require you to call 
initializers manually (and hence they're called just like any 
other function).

Just wanted to check, is this understanding correct?

(The reasoning being, if I'm writing my own little kernel, I want 
to figure out whether I should be compiling Phobos with Posix or 
with Windows, to minimize my headaches... although I should 
mention that, either way, I'm going to be developing on Windows, 
in PE format.)