The PC keyboard maps use the left Alt key as the META
key. You have two choices for emulating the SUPER and
HYPER keys: either the right CONTROL key or the right
ALT key by setting the variables dos-hyper-key and
dos-super-key to 1 or 2 respectively.
The variable dos-keypad-mode is a flag variable which controls
what key codes are returned by keys in the numeric keypad. There is
no dedicated LFD key; use C-j instead. You can also
define the kp-enter key to act as LFD, by putting the
following line into your `_emacs' file:
;; Make the Enter key from the Numeric keypad act as LFD. (define-key function-key-map [kp-enter] [?\C-j])
The key which is called DEL in Emacs (because that's how it is designated on most workstations) is known as BS (backspace) on a PC. That is why the PC-specific terminal initialization remaps the BS key to act as DEL; the DEL key is remapped to act as C-d for the same reasons.
Emacs on MS-DOS supports a mouse (on the default terminal only). The mouse commands work as documented, including those that use menus and the menu bar (see section Menu Bars). Scroll bars don't work in MS-DOS Emacs. PC mice usually have only two buttons; these act as Mouse-1 and Mouse-2, but if you press both of them together, that has the effect of Mouse-3.
The variable dos-display-scancodes, when non-nil,
directs Emacs to display the ASCII value and the keyboard scan code of
each keystroke; this feature serves as a complement to the
view-lossage command, for debugging.