41a PCI Local Bus Turns 20, PCI Express 10, PCI SIG Looks Ahead

The Peripheral Component Interface (PCI) Special Interest Group (SIG) celebrated 20 years of the PCI local bus, an I/O technology in use by computers to this date. This is also the 10th year for PCI-Express interface, which drives most of today's high-bandwidth computer devices. The SIG gave us a glimpse of what lies ahead. 

The Peripheral Component Interface (PCI) Special Interest Group (SIG) celebrated 20 years of the PCI local bus, an I/O technology in use by computers to this date. This is also the 10th year in market for PCI-Express interface, which drives most of today's high-bandwidth computer devices. The SIG gave us a glymse of what lies ahead. 

41a PCI Local Bus Turns 20, PCI Express 10, PCI SIG Looks Ahead

(Image Credit: Jonathan Zander)

The PCI-SIG notes that while the greater part of the past 20 years posed challenges related to bandwidth, the future adds newer ones, including compacting the PCI-Express interface to newer, smaller form-factors, with newer electrical configurations. This leaves bandwidth (performance) and form-factors as the two factors the SIG has to keep in mind, when drafting future standards.

Addressing the issue of performance the SIG noted that development of a succeeding standard to PCI-Express Gen 3.0, the PCI-Express Gen 4.0, is already underway. PCI-Express 4.0 will be designed to further double bandwidth over its predecessor. A single PCI-Express 4.0 lane will be able to push 16 GT/s. The SIG also touched on the concept of PCIe-attached storage, pointing out how PCIe add-on card storage devices such as SSDs and HBAs benefit from processor-integrated PCI-Express 3.0 root complexes.

Addressing the issue of portability and proliferation to newer, smaller form-factors, the SIG talked about PCIe OCuLink, a new cable-based standard (such as Thunderbolt, USB), that lets two devices communicate with each other without a host-device hierarchy, with minimal protocol overhead. The standard appears to be based on PCI-Express 3.0 x1, and offers 8 Gb/s bandwidth (single-lane). The connector is designed to support up to four PCIe lanes, resulting in a staggering 32 Gb/s bandwidth. The SIG touched briefly on upcoming standards such as next-generation form-factor that's part of the  Mini CEM specification, and the SFF-8639, a connector standard that will become relevant with PCIe-attached storage devices.