PC/104 and its long history in military applications

In the early days of modern electronics, the U.S. military was a major driving force of advanced electronic research and development. With the nuclear arms race, space exploration and exploitation, global awareness, and advanced armament development happening throughout the world, the need to push the frontiers of science and technology was a major requirement. The military’s unique working environments led to many military standards (MIL-SPECS) to ensure quality and uniformity so that the technology utilized did not fail. Though necessary at the time, these standards became lengthy, restrictive, and extremely costly to implement.

While all of this was happening, a common event seen throughout human history took shape: pressure from the civilian sector for rapid commercialization of these new advances. As uses for mainframe computers and PCs increased in the 1980s and 1990s, substantial, sustaining money began to flow to commercial entities. Industry quickly realized that more R&D funding could be found through commercial sales than government contracts, and with fewer restrictions on development and use. Global commercial competition became the driving force for high-speed innovation, and the usability and versatility of the modern PC rocketed.

To allow economies of scale, interchangeability, and interoperability throughout industry, well-defined commercial standards for computer boards, slot cards, and motherboards sprang up in an effort to fuel the accelerating growth in a logical and orderly way. Technological advances in chip design, capabilities and manufacturing, bus signaling, PCB construction, and software flourished. Competition forced increases in quality and reliability.

And militaries took notice. In the early 1990s, the U.S. military committed to moving away from MIL-SPECs wherever possible. They realized that they no longer needed to, or were able to, drive the bulk of the electronics future, and that many of their endeavors could be achieved with Commercial Off-The-Shelf (COTS) products at a much lower cost than before.

With its release in 1992, the PC/104 architecture provided an innovative, embedded commercial standard that allowed the military to move computational capabilities out of computer rooms to where they were needed most. The PC/104 architecture took the concept of the backplane on rackmount card cages and embedded it directly on the processor and peripheral modules. The result was the creation of the compact, modular stacking standard. It expanded the properties of the mezzanine concept by adding self-contained I/O connectivity and removed the weight, size, and vibrational susceptibilities of the rackmount concept. The secure stacking of PC/104 modules through inter-board bus connectors and standoffs provided an architecture with built-in baseline ruggedness. By promoting an evolutionary electrical bus (ISA, PCI, and PCI Express) and mechanical design philosophy, backward and forward compatibility were achieved. Predefined bus pin-outs, connector placements, and form factors allowed for interchangeability and interoperability across manufacturers to increase maintainability and upgradability of systems (Figure 1). All of this pro-vided an avenue for total project lifetime cost reductions – a quality very important to military acquisition.

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Figure 1: PC/104 combines backward and forward compatibility, interoperability, and a rugged small form factor that make it well suited for mission-critical applications and acquisition budgets.
(Click graphic to zoom by 1.9x)

Since its beginning, militaries have continued to leverage the benefits of the PC/104 architecture to increase their capabilities both directly (being able to put embedded computational power where it was needed, thereby breaking the umbilical cord) and indirectly (freeing up space for other technologies with the removal of large card cages when they were not needed).

PC/104’s rugged, modular, embedded architectures continue to be standards of choice for many military designers. For the last 20 years, PC/104 products have found themselves in all sorts of military applications, from benign environments to the worst of conditions, including guidance and navigation systems, munitions, rockets, tanks, UAVs, atmospheric monitoring, and space assets to name a few. And, as new technologies develop, PC/104 continues to rise to the occasion.

For more information visit the PC/104 Consortium website at www.pc104.org.