That explains it, thank you. 
Now only how come that
"dmd hello.d" results in a 1.70 mb application whereas
"dmd -c hello.d" && "dmd hello.obj phobos.lib" results in a 144 kb app
(sorry for confusion, Turns out I didn't link my app with phobos.lib but recompiled the object file with phobos.lib

2011/8/20 Kagamin <spam@here.lot>
maarten van damme Wrote:

> But where does the lib file searches for the dll file? how can we control
> that? Is my hunch right?

The dll is searched by the system. It's a documented procedure. You can control it to some degree by manifest files.