Intel integrated RAID (Redundant Array of Inexpensive Disks) module provides reliability, high performance, and fault-tolerant disk subsystem management. Acomplete fault-tolerant strategy requires protection of all data, including the unwritten cached data in the RAM cache. If power is lost, the data in the RAM cache is lost. To avoid data loss, a RAID Maintenance Free Backup Unit (RMFBU) can be added to store unwritten cached data from the RAID RAM during an AC power outage or if the AC power cord is removed.