US Patent 7676682 Lightweight management and high availability controller

A network storage appliance having a main computing unit is provided with an embedded microcomputer for monitoring startup and operation of the main computing unit. The microcomputer has the ability to restart, power down or power up the main computing unit if any corresponding predetermined conditions exist. Local nonvolatile storage holds the firmware for the main computing unit and configuration for the appliance. After loading the firmware and configuration to the main computing unit, the nonvolatile storage is electronically disconnected from the main computing unit. Where two such appliances are coupled for redundancy between the same network storage and the network, the embedded microcomputers are separately coupled for communication to allow for negotiating a restart of one of the main computing units under the direction of the other, or if any predetermined conditions occur.