os.mkdir() errno inconsistency on Windows?

[Tim Peters]

[Irmen de Jong]
> On windows (2000), Python 2.1:
> Why does os.mkdir() return a different errno when trying to create an
> already-existing directory, or trying to create the drive root directory?

Only Microsoft knows:  Python reports the errno value set by Microsoft's
_mkdir() function.  You'll see the same values if your do the same things
from C code.