content: The hp48 is much more sophisticated press and hold [ON]. press and release [A] and [F].    if you now release [ON] you will coldboot the operating system (memory clear). You also get a prompt "Try to recover memory?".  If you realise you do not want to erase the memory, before releasing [ON] you press and release [B] and then release [ON]. Pressing and releasing [B] aborts the coldboot procedure.  [ON][SPC] puts the calculator in "coma mode". All functions off to conserve memory and the only thing powered is the main ram,whi  1000  ch is powered from an emergency capacitor. This is for the case where battery is running low but you don't have the option to swap out the batteries for new ones in a short time.