PICMG then and now - A story of responding to customer needs
For the past 20 years, the PCI Industrial Computer Manufacturers Group (PICMG) has been developing standards that enable industrial computing customers to deploy the latest technology while taking advantage of time-to-market and hardware cross-compatibility inherent in open standards. This article explores the early days of PICMG and how the organization continues to evolve to meet the needs of industrial customers deploying technology in a wide range of applications.
Prior to Intel’s creation of the PCI bus in the early 1990s, the ISA bus was essentially the only viable board interconnect game in town for Single Board Computers (SBCs), backplanes, and peripheral cards used in industrial computing applications. Figure 1 illustrates one of these early ISA-only SBC and backplane hardware combinations. Intel’s creation of the PCI bus was followed by the PCI-SIG’s publication of the PCI bus industry standard. This initial standard publication was open ended to account for every possible application scenario. Unfortunately, this resulted in companies with differing implementation ideas embarking on separate technology paths for developing SBCs and backplanes to incorporate this new bus technology. The net result was products that were in essence sole-source hardware because these early PCI bus-driven SBCs and backplanes were oftentimes incompatible with products from other companies. This proved to be a system application and business nightmare for customers needing flexible, robust, and long-life industrial computer platforms.
After a period when companies were trying to sell their unique board solutions, several key customers stepped in to demand a better way forward. As an example, a major impetus to start PICMG was provided by a global medical diagnostic machine maker when they reacted to some early PCI/ISA-based SBCs and backplanes from Trenton Systems by saying, “Great idea folks. Love the technology, the system interoperability, improved configuration flexibility, and the added system performance, but we’re not interested in adopting a single source for any new technology that is going to run our new CAT scan machines.”
How many times have you received a phone call that changes the course of events in either your personal or professional life? Some of these calls are good calls, and one such “good call” came in late 1993 when Pierre McMaster from Teknor Microsystems called Roger Hurlbert, one of Trenton Systems’ co-founders, to discuss this hardware interoperability problem. During this call Pierre wanted to see if Trenton Systems would be interested in working together to develop a common industry standard to extend the PCI standard to incorporate this new, faster, and more functional bus into a series of cross-compatible industrial SBC form factors.
Both Teknor (now part of Kontron) and Trenton Systems (at the time known as Trenton Terminals) began to canvas other board and industrial computer manufacturers about the possibility of coming together to form a new consortium to develop an industrial standard that integrated PCI bus technology with existing ISA technology. The idea was to develop an industry-standard SBC interconnect methodology that could use standard passive backplanes to support both the existing ISA cards as well as new PCI-based I/O, video, and data collection boards.
First PICMG meetings
In May of 1994, Teknor Microsystems, Trenton Terminals, I-Bus Maxwell Laboratories, and Texas Microsystems met in Philadelphia, PA to discuss the merits of different SBC and backplane designs, some new PCI-ISA and PCI-to-PCI bridge technology, as well as other technical issues regarding edge connector form factors, connector pin-outs, signal interfaces, and bandwidth capabilities. During this meeting Trenton Terminals presented an SBC prototype based on the incorporation of two innovative PCI and ISA card edge connectors.
After some discussions, tweaking, and fine tuning, it was agreed that the SBC board design presented would form the basis of a new industry standard that would extend the PCI standard to include industrial passive backplane systems. This standard system architecture enabled customers to reduce Mean-Time-To-Repair (MTTR), improve peripheral board interoperability, and maintain backward compatibility with the old ISA bus while capitalizing on the promise of PCI expansion bus and CPU independence to enable true auto-configurability in an industrial computer.
These four companies came together with the help of Rogers Communications to officially form PICMG, and by October of 1994 had formally organized and released the first PICMG specification: PICMG 1.0 – PCI-ISA Card Edge Connector for Single Board Computers. Figure 2 illustrates one of these early PICMG 1.0 SBCs.
First PICMG products introduced
In November of 1994, the infant PICMG organization presented the new industry standard at COMDEX and invited other companies to join PICMG to work on “extending the PCI standard to encompass industrial applications.” Many new companies joined PICMG, with two key players – Pro-Log and Ziatech – leading the effort to create a new standard called CompactPCI (cPCI), or PICMG 2.0. Past and present PICMG member companies remain focused on enabling customers in industries such as industrial automation, medical, military, and telecom to deploy the latest technologies with the multi-source confidence provided by computing systems based on open standards.
CompactPCI leads to rapid PICMG expansion
Lead by Joe Pavlat at Pro-Log and Jim Medeiros at Ziatech, the cPCI base standard merged the Eurocard form factor and a series of IEC-approved and Bellcore-qualified high-density 2 mm pin-and-socket connectors into a new industrial computer form factor standard that was well suited for telecom and military computing applications. Diverse aerospace applications for CompactPCI systems range from orbiting satellites to a dual cPCI system powering the Mars Rover, Curiosity. Figure 3 illustrates the typical 6U form factor of a cPCI SBC and Rear Transition Module (RTM). The positive card retention engineered into the cPCI board form factor enabled system designs with excellent shock and vibration characteristics. Some of the other application needs addressed by the initial cPCI base specification included:
- 3U and 6U vertical card orientation for simplified system cooling with easy card access
- User I/O connections on the front and/or rear of the processor module
- Staged power pins to support module hot swap capability
With the creation of cPCI and all the related PICMG 2.x standards, the PICMG organization took off for a variety of reasons, with the fundamental one being that, like PICMG 1.0, PICMG 2.0 was the answer to a number of specific customer technology needs.
PICMG standard-based computing leads the way into new technology implementations
Since these rather humble beginnings, PICMG continues its heritage of responding to customer needs with the adoption of several new standards that leverage new multicore processor and high-speed serial interface and fabric technologies. Computer system integration and performance advantages are made possible by serial/fabric interconnects such as PCI Express (PCIe), Fiber Channel, InfiniBand, and Rapid I/O. PCIe is proving to be one of the more popular and cost effective of these new interconnects and is incorporated into several new PICMG standards including CompactPCI Express (PICMG EXP.0), AdvancedTCA (PICMG 3.x), MicroTCA (PICMG MTCA.x), SHBExpress (PICMG 1.3), and COM Express (PICMG COM.0 and CDG). Figure 4 shows just a few examples of some of the new hardware platforms utilizing fabric-based standards.
These base standards, plus all of the related standard extensions, enable customers to deploy standard industrial computer systems in a variety of different processor board form factors that fully utilize PCI Express.
PICMG going forward
PICMG has come a long way in the last 20 years, from four member companies developing a single industrial computer standard to over 250 member companies developing and implementing products based on over 70 industry-accepted standards designed to meet customer application requirements. As new computing and interface technologies are invented, PICMG stands ready to develop the necessary industry standards that enable customers to implement new computer technologies faster and with less risk while enjoying the reduced costs associated with vendor competition and the economies of scale inherent with standards-based computing systems.
Trenton Systems, Inc.
PCI Industrial Computer Manufacturers Group (PICMG) firstname.lastname@example.org