Investment protection - Comment

Electronic News, Feb 11, 2002 by David Dorrough

A NEW GENERATION OF PCI technology is almost here. Within the coming weeks, the PCI Special Interest Group will introduce a new PCI-X specification that will once again double and quadruple performance-ultimately achieving I/O bandwidth that is 32 times faster than the PCI that was originally introduced eight years ago. This new technology, PCI-X 2.0, will make it possible to drive new, faster applications such as 10 Gigabit Ethernet, 10 Gigabit Fibre Channel, 4X Infini-band and other customized applications. The net result will be faster networking and storage applications for higher overall system performance.

The PCI-X 2.0 specification is being released at a time when the market is currently flooded with I/O interface choices for chip-to-chip interconnect, expansion slots, and external I/O. From ServerWorks' perspective, PCI-X 2.0 is the obvious choice for expansion 110 in high-bandwidth applications because of its high performance, backward compatibility and ease of implementation.

The new PCI-X 2.0 standard achieves its performance via time-proven double data rate (DDR) and quad data rate (QDR) techniques that transmit data at either two times or four times the base 133MHz clock rate, effectively transferring 2 bits or 4 bits of data per clock cycle. Because it operates on a 133MHz clock and uses the standard 64-bit data bus, it achieves a bandwidth of up to 4.3Gbytes per sec.

Although the technology is applicable to any computer, the most natural fit for this high-performance I/O interface is in platforms such as enterprise servers, professional workstations, high-end UNIX servers, mainframes and networking applications. Even as the specification is being finalized, the leading vendors have already begun to design PCI-X 2.0 systems that will be ready for production early next year.

PCI-X 2.0 is also completely backward compatible. Even first-generation, legacy PCI adapter cards can plug into the highest-performance PCI-X 2.0 slots and operate seamlessly. To make things even better, the converse is also true. High-performance PCI-X 2.0 adapter cards can operate in the PCI slots that still exist from past-generation computers. If the slot can't meet the performance of the card, or vice versa, the operating frequency will be throttled to meet the maximum frequency of the limiting device. There are no jumpers to set, no BIOS settings to modify, and no software upgrades are required. It just works!

Not only is the forward and backward compatibility convenient, it also offers a tremendous advantage for system manufacturers and consumers since every slot is usable. In fact, there are already hundreds of I/O adapter cards that can plug into all the new PCI-X 2.0 slots. Whether it's a high-performance networking card, a specialized imaging card or that long-forgotten Telco card, they will all work in new PCI-X 2.0 slots.

PCI-X 2.0 design and implementation are easy because the specification is heavily leveraged from previous generations of conventional PCI and PCI-X 1.0. For example, PCI-X 2.0 uses a nearly identical bus functional model (BFM) as PCI-X. In addiion, the device drivers remain he same. The board layout is easy because the PCI-X 2.0 extensions are point-to-point and require only minor guideline modifications. Also, chipset manufacturers and adapter card vendors are able to create parts that have the same pinouts as their current PCI-X interfaces. Designers are already familiar with the technology, and in many cases the same design tools can be used. Finally the same proven 64-bit connector is used. The fact hat so many previously designed elements are in place significantly improves product development time and time-to-market, while lowering development risk.

The PCI standard has a long, successful history of enhancing bus capabilities while protecting the sizable investments of the industry. It began as a comparatively low-performance 33MHz standard. Over time it has evolved; each standard has built upon the previous one to meet the performance requirements of its generation. Each generation has been well received because full software and hardware backward compatibility has been faithfully maintained. As a result, risk has been mitigated, and migration time has been significantly reduced. The next step in this highly successful legacy is the brilliant PCI-X 2.0 specification. Server Works believes that PCI-X 2.0 is destined to be equally successful because it offers the performance needed for today's and tomorrow's applications in an easy-to-adopt, evolutionary standard.

David Dorrough is the technical marketing manager for ServerWorks Corp., a Broadcom company.