After effectively superseding the PCI bus, PCI Express interconnect technology is now entrenched in its early high-growth markets: PCs, workstations, servers, and storage systems. It has started to penetrate other markets as well, and it is on track to become more popular than any previous interconnect standard. This success has come about for two reasons.
First, PCI Express is a powerful, state-of-the-art serial interconnect, so it suits a wider variety of platforms than the older PCI bus. Second, the PCI-SIG, the special interest group responsible for PCI and PCI Express, learned from its PCI bus experience and more completely defined the necessary capabilities into the PCI Express specification from the start. Important features such as Hot-Plug, connectors for more usage models, and quality of service were all included from the outset.
But the job is not done. The market has progressed, and before PCI Express can further penetrate the modern storage market—as well as accelerate its reach into other markets—more standardization of capabilities will be necessary. And while larger companies dominate most standards bodies, including the PCI-SIG, small innovative companies often push the envelope in identifying and enabling these newer markets.
The storage market, for example, desires the ability to send the same information to several subsystems simultaneously for purposes of data integrity. To enable this, there is presently a version of this capability—Dual Cast. At the same time, we’re working with a group of like-minded vendors to develop a more general-purpose multicast feature for the PCI Express standard.
To allow PCI Express to quickly break into newer markets such as enterprise bladed, communications, and embedded systems, other capabilities need to be addressed, such as I/O virtualization and interprocessor communication. And as system needs become more focused and platform-specific, nimble companies with expertise in this area will take the lead in enabling standardized features.
Small, focused companies also offer features that supplement the PCI Express standard and don’t necessarily need to be a part of it. For instance, a new feature in switches called Read Pacing works within the existing standard but provides better performance on platforms than heterogeneous data types. Additionally, there’s now the ability to dynamically allocate how memory is used within a switch, putting more internal storage to work where it will offer the best performance, based upon system needs.
With its unprecedented speed and flexibility, PCI Express has the opportunity to become the universal interconnect, powering every type of platform. Standardizing key features is essential to realizing its full potential, and the efforts and guidance of small, focused companies provide an important, innovative service to the interconnect ecosystem.
