Here is some trivia for you...PC-DOS 1.0 like CP/M didn't support sub-directories. It wan't until PC-DOS 2.0 that sub-directory support was added. The character \ was only used with drive letters since drive letters were the only paths that existed.

For example you could copy the file test.doc from the A:\ floppy drive to to the C:\ hard drive with the command:
A:\copy test.doc C:

The command interpreter for PC-DOS 1.0 supported the following commands:

  • DIR, TYPE, COPY, ERASE, RENAME
  • PAUSE, REM

No pipes, redirection, or device drivers were supported.