The Smart Battery supports RAID controllers that use a standard 128 MB or 256 MB DDR2 DIMM. It is available as an accessory for selected RAID controllers. Intel® RAID Smart Battery AXXRSBBU6 contains the following components: -Board-to-board connector: The AXXRSBBU6 can connect to the base controller through the connector as a daughter card to the base controller. -Smart Refresh Circuit board: Ensures that the battery is maintained at optimal performance and charge levels. This circuit is based on the Texas Instruments bq2060A SBS v1.1-Compliant Gas Gauge IC. -5-pin connector cable: Allows communication between the Smart Refresh Circuit board and the battery pack. -Battery pack: Includes a circuit logic board and attached Li-ion batteries. The logic board provides sensing and management logic to support the battery charge, discharge, and monitoring functionality. -Software: Notifies the user of failures or corrective actions. Monitoring is accomplished through the Intel® RAID BIOS Console 2, Intel® RAID Web Console 2, or command line Tool 2 utilities. The battery pack charges automatically and communicates battery status information, such as voltage, temperature, and current, to the host computer system. Because it is faster to write data to the RAID adapter’s cache memory than it is to write it directly to a storage device, data is first written to the cache memory. These write operations complete quickly at the software application level. The RAID controller then writes the cached data to the storage device when system activity is low or when the cache is full. This method of writing data carries a risk. Cached data on the RAID controller can be lost if the AC power fails before it is written to the storage device. The Smart Battery mitigates this risk by providing battery power to the RAID controller if AC power is lost. The Smart Battery monitors the voltage level of the DRAM modules on the RAID controller. If the voltage drops below a defined level, the Smart Battery switches the memory power source from the RAID controller to the battery pack. The battery pack provides power for the memory until the voltage returns to an acceptable level, at which time the Smart Battery circuit board switches the power source back to the RAID controller. Cached data is then written to the storage devices with no loss of data. The Smart Battery provides additional fault tolerance when used with a UPS. The battery pack cache-memory hold time depends on the size and configuration of the RAID controller memory. Retention time depends on memory capacity and the number of memory components on the DIMM to support the capacity. Estimated battery backup retention time is 72 hours.