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 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 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.
(keymap-set function-key-map "<kp-enter>" "C-j")