For command prompt : For windows explorer : Why is this so? Inorder to find out why this doesn’t work we have to go back to the age of MS-DOS. Microsoft Disk Operating System (MS-DOS) is a command-line operating system that existed before the advent of GUI OS (Graphical User Interface). Everything from making ,renaming, deleting etc was done using commands. Some of the commands are… Let us look more closely to the COPY command. The COPY command usage is as follows: In DOS everything is considered as files, even keyboard and printers. The filename for keyboard is given as “CON” and the printer names are given as “LPT1”, “LPT2” etc.. So inorder to copy something from keyboard (our input) the following command is used.
So now you suppose that a folder or file named “con” could be created and you give a COPY CON command. What is DOS supposed to do? copy the CON file or use the keyboard console as input? Thus an ambiguity arises. So Microsoft has purposely disabled making of files or folders named CON / LPT1 / LPT2 etc. in order to remove this ambiguity. Could you make a CON or LPT1 .. file on WINDOWS? Found more invalid names? Let me know …..Invalid Name List : ####################################################
