Abstract: A data processing system boots at least one service processor controlling at least one PCIe card in an I/O unit. The data processing system boots a second service processor located in a processor unit, wherein the processor unit and I/O unit are interconnected using functional path conductors, wherein functional path conductors are according to PCIe standard. The data processing system reads location information from the first at least one service processor, wherein the location information is reported for each PCIe card prior to initializing a functional path to the PCIe card. The data processing system sends location information from the second at least one service processor to a system controller. The data processing system initializes the PCIe card and a hub card of the processor unit in order to initialize a functional path and configures the I/O unit by communicating configuration commands over the functional path.