The 'CON' Folder

The word "con" is an abbreviation for "console". Depending on what you are trying to do, e.g. program the creation of a folder called 'con', you may get an error. This is because 'con' is a reserved name for writing to an output reserved for the console, typically the operator's screen.

It is a special name in MS-DOS and Windows – one which refers to the system console. If a console application writes to the file "con", whatever is written there will appear on the screen. It is roughly equivalent to the special file in UNIX. Since it is a special file name, it already exists – and if it exists, you cannot create it – neither as a file nor as a folder. Other such special names are NUL, LPTn and COMn (where "n" is a digit). They refer to the "no device" (dev/null in UNIX), the printers and the communication ports respectively.

All these special names have little meaning nowadays when most people use GUI programs, but they still exist as a legacy and cannot be created.

As DOS users will tell you, the words CON, PRN, LPT etc. have special a meaning in DOS and are called "Reserved Words". The user is forbidden from having files or folders whose name is the same as a reserved word.

Windows is a "shell" or "program" running on top of DOS. So, you cannot have user defined objects in Windows that have the same name as a reserved word in DOS.