Overview

The best way to predict the future is to invent it.

Alan Kay

This chapter looks more closely at the applications where PCI Express offers significant benefits beyond existing interconnect technologies. PCI Express is a unique technology in that it provides immediate benefits across multiple market segments from desktop PCs, mobile PCs, enterprise servers, to communications switches and routers. This chapter starts with a brief overview of the key benefits of PCI Express and then covers the applications where PCI Express is a natural solution due to evolving requirements. Finally this chapter reviews some of the applications where PCI Express provides a new and revolutionary usage model.

Benefits of PCI Express

PCI Express provides benefits across five main vectors: high performance, I/O simplification, layered architecture improving serviceability and scalability, next generation multimedia, and ease of use. These benefits come at a very small impact to software. The software driver model of PCI Express is backward compatible to the PCI software infrastructure. Unlike parallel bus architectures such as AGP8x and PCI-X, future scalability to higher bandwidth can be achieved due to the layered architecture without compromising the software compatibility. For example, future speed upgrades are possible through a change in the Physical Layer while not impacting the Data Link Layer or Transaction Layer. A full discussion on the various layers can be found in chapters 5 through 8. This section briefly discusses the benefits for each topic in Figure 4.1.

Figure 4.1: PCI Express Benefits