This write-only action object restarts a chassis subsystem, offering a warm start with save, a cold start, or a warm start without saving configuration. An admin picks the restart mode based on whether pending configuration changes should be preserved (warmstart-with-save) or discarded, and whether a full hardware reset (coldstart) is needed to clear a hung state. For example, setting this object to coldstart(2) forces a full hardware reset of a subsystem that is unresponsive to a warm restart.