Try to create a folder named CON or PRN in windows. You wont be able to create one..

In order to ensure backward compatibility with DOS, Microsoft has reserved keywords like the following”CON, PRN, AUX, CLOCK$, NUL, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, and LPT9″
These Names Represents Device Names Which were used in the MS-DOS Days..
Example : Con Represents “CONsole”
You Can Create Folder Like ‘con’ or any other with the following command in the dos prompt
example : mkdir \\?\C:\con
And Remove it with the following command
example : rmdir \\?\C:\con [/m