Abstract: A power supply system for use in a fault-tolerant computer having a main bus interconnecting several main bus elements, with at least one of the elements being capable of transmitting commands and receiving status information. The system includes a status bus which is coupled to the main bus. A control unit is associated with each bus element, such control unit including a voltage regulator connected to a primary source of power for providing regulated voltage to the associated bus element in response to commands received over the status bus from the main bus. The primary power source preferably includes redundant power supplies which provide voltage which is distributed over a pair of redundant voltage buses. Apparatus for sensing when a main bus element has seized the main bus may be included so that the bus element can be commanded by way of the status bus to release the main bus.