IBM zEnterprise® 196 introduces a new input/output (I/O) s5ubsystem, including a new I/O drawer that is largely based on a greatly expanded exploitation of industry-standard high-volume PCI Express® (PCIe®) links and switches. The System z® qualities of reliability, availability, and serviceability (RAS) are preserved and enhanced by combining the PCIe RAS capabilities with new System z capabilities. PCIe ports connecting the processor book to the I/O drawer are provided by a new IBM-designed PCIe fan-out card. This fan-out card and its firmware (Licensed Internal Code) support both traditional System z I/O and new I/O paradigms. In the new PCIe I/O drawer, PCIe switches provide fan-out and the well-established System z I/O failover function referred to as redundant I/O interconnect. This is the third generation of the I/O drawer/cage to be used in System z platforms. The PCIe I/O drawer design is extremely compact and provides enhanced I/O port granularity and density. It has been designed to provide performance extendibility for future I/O advancements. Traditional I/O such as FICONA, Fibre Channel Protocol, and Ethernet are provided with enhanced functionality and are packaged in this new PCIe I/O drawer. The advent of this new infrastructure opens up the possibility of attaching native PCIe adapters while allowing them to be controlled by system firmware or by the operating systems directly.