This read-write attribute triggers a restart of the ComController: warmStart(2) reboots using the currently active software load, while coldStart(3) reboots and also refreshes the active firmware images and configuration file from NMAPS, with completion signaled by a standard SNMP warmStart or coldStart trap. This is a headend-wide operation affecting every STU the controller serves, so it's a much heavier action than the equivalent per-device stuRestartAction and is typically reserved for maintenance windows or recovering from a bad configuration. For example, after discovering the active configuration file on a headend was corrupted, an operator would set hcxRestartAction to coldStart specifically to force the controller to re-pull a clean configuration from NMAPS.