If HW fails, like RAM gets corrupted or a HD dies while the OS is running, what else are you gonna do but halt and display what the cause was inasmuch as you can tell? I remember our HP3000 mini computer would kamikaze like that (crash) when critical HW failed, at which point you would load up a blank magtape, take a memory dump, and analyze the 6″ brick of paper to figure out why the OS couldn’t keep running.