I did know that. The point is that unlike Unix, MS-DOS had no FHS to go with its hierarchical file system, which would cleanly separate the namespaces of user files from device nodes. (The file system layout didn’t even start becoming standardised until the Windows 95 days.) One could fairly legitimately create a DEV directory in the root of the file system and expect to be able to keep their own files there, naming them arbitrarily. The edge case is now harder to hit, but it’s still basically the same mistake.

DJGPP even has a FAQ item about a similar issue: <http://www.delorie.com/djgpp/v2faq/faq22_21.html> (though that one is caused by DJGPP’s own Unix emulation layer)