Patent ID: 7468597

Claim:
A method to supply power to one or more battery-backup assemblies disposed in an information storage and retrieval system, comprising the steps of: supplying a first controller comprising one or more host adapters, one or more device adapters, a processor, cache, memory, and a Fibre Channel switch, and having a first controller load, and a second controller comprising one or more host adapters, one or more device adapters, a processor, cache, memory, and a Fibre Channel switch, and having a second controller load; supplying a first battery-backup assembly having a first BBU load, wherein said first battery-backup assembly is external to and interconnected with said first controller, and a second battery-backup assembly having a second BBU load, wherein said second battery-backup assembly is external to and interconnected with said second controller; supplying a power bus interconnected to said first controller, said second controller, said first battery-backup assembly, and said second battery-backup assembly; supplying a first power supply interconnected with said power bus; supplying a second power supply interconnected with said power bus; providing power to said power bus from said first power supply and from said second power supply; drawing power from said power bus by said first controller, and said second controller, and said first battery-backup assembly, over a first period of time; and drawing power from said power bus power by said first controller, and said second controller, and said second battery-backup assembly, over a second period of time, wherein said first period of time differs from said second period of time.