As VDC has conducted its researchthroughout 2011, a number of embedded board specification challenges have continuously collided with practical implementation practices. In the PC/104 stackables market, for instance, significant differences have emerged in the standards being developed by the PC/104 Consortium and Small Form Factors SIG. Underlying this split are a host of issues surrounding design philosophy and the roadmap for implementing future technology while continuing to support legacy devices.
Both groups acknowledge that the ISA and PCI bus are becoming more difficult to implement as the stackables architecture evolves. Originally, the PC/104 architecture (deployed into the market in 1992) supported the ISA bus. The next generation of stackables was PC/104-Plus which supported both the ISA bus and the faster, higher-bandwidth PCI bus. It was at this point that the PC/104 Consortium and the Small Form Factors SIG took different roads, with the Consortium releasing PCI/104-Express and SFF SIG developing SUMIT-ISM. The PCI/104-Express stopped supporting the ISA bus since the Consortium felt that the ISA bus was declining in use. However, SFF SIG believed that customers still wanted the ISA bus to support longer-life legacy equipment into the future. From SFF SIG’s perspective, the consequences for legacy users who use PCI/104-Express include the need for a PCIe-to-ISA adapter board, possible BIOS changes, additional cost and stack height, and possible I/O board redesign.
Yet, despite their differences, the specification groups have their common ground. Both groups believe in supporting the PC/104 stacking architecture, the 90x96mm boards are important to customers, and there is a need for high speed serial buses. No doubt both groups are trying to meet customers’ future needs while transitioning them appropriately from legacy hardware. VDC sees there are some key questions that remain to be answered surrounding what I/O should be supported and how long a lifecycle should stackable solutions satisfy. Ideally, the two groups can come together in the future to avoid customer confusion and fragmentation of the market along different standards indefinitely.