Apparatus and methods for converting a processor, having a plurality of states and being operative to execute software operations stored in a memory device, into a self-stabilizing processor, comprising providing self-stabilizing watchdog hardware that, with given timing, interacts with the processor, in accordance with an interaction sequence that includes at least one trigger that sets the processor to a known state from among a set of at least one known states. Also described are applications for stabilization of operating systems and other hardware or software configurations, apparatus and methods for ensuring eventual invariance of software executed by a processor, and apparatus and methods for enforcing fixed software configurations.