Terry J. Reedy <report@bugs.python.org> wrote:
> mkdir: 242
> Traceback (most recent call last):
>   File "C:\Programs\Python31\misc\t1.py", line 14, in <module>
>     os.mkdir(s)
> WindowsError: [Error 206] The filename or extension is too long: 'C:\\Programs\\Python31\\misc\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab\\aaaaab'

On Windows MAX_PATH seems to be 260 characters:

http://msdn.microsoft.com/en-us/library/aa365247(VS.85).aspx