content_image/1001609.jpg content_image/1001610.jpg
The domains and their related I/O slots are shown in Figure 4-4. 

<img src='content_image/1001609.jpg'>

Each I/O domain supports up to eight features (FICON, OSA, Crypto, and so on.) All I/O cards connect to the PCIe switch card through the backplane board. The I/O domains and slots are listed in Table 4-1. 

<img src='content_image/1001610.jpg'>

## 4.4 PCIe I/O drawer offerings 

A maximum of five PCIe I/O drawers can be installed that support up to 160 PCIe I/O features. 

For an upgrade to IBM z14™ servers, only the following PCIe I/O features carried forward: 

GLYPH<SM590000> FICON Express16S 

GLYPH<SM590000> FICON Express8S 

GLYPH<SM590000> OSA-Express5S (all 5S features) 

GLYPH<SM590000> OSA-Express4S 1000BaseT (only) 

