We technophiles love forklift upgrades; when faced with a new design challenge, our first impulse is to create the most elegant architectures from scratch, without regard for business issues like cost and time-to-market. But most companies prefer an evolutionary approach, gradually upgrading and squeezing more life from existing hardware and software. Time-to-market for new equipment is dramatically lower with this approach.

The communications arena is littered with once-elegant ideas that are now marginalized. Worldwide, tons of government and private money has been spent on forklift upgrades, such as high-speed fiber-optic and satellite communications to replace the trusty twisted-pair phone lines. Yet in terms of market acceptance and actual deployment, twisted pair carrying high-speed modem and DSL traffic is significantly ahead of the more revolutionary approaches. Squeezing more performance out of the twisted-pair infrastructure has enabled gradual and relatively low-cost upgrades of existing networks.

A similar story is unfolding in systems backplanes. Engineers designing comms equipment, PCs and servers have long used the Peripheral Component Interconnect architecture as a system backplane. When the speed, scalability and reliability requirements of modern communications systems eclipsed the original 32-bit, 33-MHz PCI, enticing forklift upgrades appeared. Infiniband, for one, claimed breakthrough performance but at the cost of major changes to system software and hardware. Consequently, Infiniband, while successful as a storage-area network interconnect, is gaining little traction as a PCI replacement in communications systems.

Instead, an evolutionary approach is winning out. PCI is evolving to 64 bits and 66 MHz and beyond. CompactPCI, a mechanical form-factor variant, improves system scalability and reliability, while Switched-PCI delivers breakthroughs in bandwidth, scalability and high availability. All these PCI flavors are interoperable; hardware and software built around different versions work together.

Taking the evolutionary approach further is third-generation I/O, or 3GIO. While revolutionary in its scalable 2.5-Gbit/ second communications channels, 3GIO promises another upgrade path for PCI-based systems. It is being defined to be compatible and interoperable with PCI, creating a smooth, logical, evolutionary-upgrade path. That keeps engineers within the parameters of cost and time-to-market and, more important, it makes business sense. These developments should help keep the forklifts parked way in the back of the warehouse.

MIchael Salameh is Founder and President of Plx Technology (Sunnyvale, Calif.).