A system controller module is operable to monitor system operation in a system that can include a further such system controller module. The system controller module can include system controller storage and can be operable to maintain system parameters therein. At least a predetermined part of the system controller storage can include a plurality of domains. A check code (e.g., a pseudo CRC) can be generated for each domain such that equivalence between check codes for a domain in the system controller storage and a corresponding domain in further storage of a further system controller module is indicative of the domains concerned being in synchronism.