Any technology, especially when it is new, requires careful nurturing and more importantly needs a set of well defined criteria by which implementations can be judged against the technology s relevant specifications. There have been such criteria for other PCI technologies in the past and efforts are underway to do the same for PCI Express. These criteria essentially address two aspects of a PCI Express device or function Compliance and Interoperability (C&I). A function here refers to a component like BIOS and not a PCI Express function. It is worth noting that while compliance and interoperability are necessary, neither alone is sufficient by itself. A product must be both compliant and interoperable. This section is intended to show how the C&I criteria as well as the tools and mechanisms to test for adherence to that criteria are developed. It is highly recommended that readers of this book go to the PCI-SIG website to get the latest details on the recommended procedures. In particular, every vendor contemplating a PCI Express product is encouraged to pay special attention to the compliance and interoperability requirements. If the compliance and interoperability requirements are not satisfied, they could become a stumbling block in getting products to market.