Abstract: An improved redundant computing apparatus includes a chassis assembly configured to (i) mount to a standard electronic equipment rack and (ii) consume substantially 1U of space in a particular direction (e.g., vertical height) within the standard electronic equipment rack. The chassis assembly includes a housing and a midplane disposed within the housing. The apparatus further includes a set of power supply/blower assemblies configured to connect to the midplane of the chassis assembly through a front of the housing in a field replaceable manner, and a set of computing devices configured to connect to the midplane of the chassis assembly through a back of the housing in a field replaceable manner. By way of example, the set of computing devices is adapted to move data into and out of a set of disk drives on behalf of a set of external host computers.

Abstract: In a system comprising a plurality of components, characteristic data is stored on programmable read-only-memories (PROMS) on each component. The PROMs are coupled together via a simple bus, and data is retrieved from the PROMs using the bus. The collection of data from the PROMs provides the component characteristic data, and a portion of the component characteristic data is stored in one or more persistent media devices in the system, creating a last known good copy. The persistent storage device could be any device that does not lose data in the event of a loss of power.