INT 21 - Novell NetWare shell 3.01 - MAP A FAKE ROOT DIRECTORY
        AX = E905h
        BL = drive number (0=default, 1=A:, ...)
        DS:DX -> ASCIZ path for fake root (may include server name or be empty)
Return: CF set on error
            AL = error code (03h,0Fh,11h) (see AH=59h)
        CF clear if successful
Note:   if drive is not currently mapped, a drive mapping will be created