G.10.1 Keyboard Usage on MS-DOS

The key that 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 <DELETE> key is remapped to act as C-d for the same reasons.

Emacs built for MS-DOS recognizes C-<BREAK> as a quit character, just like C-g. This is because Emacs cannot detect that you have typed C-g until it is ready for more input. As a consequence, you cannot use C-g to stop a running command (see section Quitting and Aborting). By contrast, C-<BREAK> is detected as soon as you type it (as C-g is on other systems), so it can be used to stop a running command and for emergency escape (see section Emergency Escape).

The PC keyboard maps use the left <ALT> key as the <META> key. You have two choices for emulating the <SUPER> and <HYPER> keys: choose either the right <CTRL> key or the right <ALT> key by setting the variables dos-hyper-key and dos-super-key to 1 or 2 respectively. If neither dos-super-key nor dos-hyper-key is 1, then by default the right <ALT> key is also mapped to the <META> key. However, if the MS-DOS international keyboard support program ‘KEYB.COM’ is installed, Emacs will not map the right <ALT> to <META>, since it is used for accessing characters like ~ and @ on non-US keyboard layouts; in this case, you may only use the left <ALT> as <META> key.

The variable dos-keypad-mode is a flag variable that controls what key codes are returned by keys in the numeric keypad. You can also define the keypad <ENTER> key to act like C-j, by putting the following line into your ‘_emacs’ file:

;; Make the <ENTER> key from the numeric keypad act as C-j.
(define-key function-key-map [kp-enter] [?\C-j])