Hardware features are packaged in two different forms: System Product Division (SPD) or Peripheral Component Interface (PCI), depending upon the server model.
SPD I/O adapters (IOAs) are packaged with I/O processors (IOPs) and do not require a separate card position. The device connects to the slot containing the IOA and the IOP.
PCI IOAs are packaged separately from the IOP and require a separate card slot. The IOP in a card position is connected to the IOA in another card slot. The device attaches to the IOA.