The VMEbus architecture has delivered significant long term benefits to its many thousands of users worldwide – including many thousands of GE Fanuc Intelligent Platforms’ customers. Its strength has been its ability to evolve, to adapt to new technologies and to embrace them, bringing increasing processing power while minimizing – and in many cases eliminating – the costly and time-consuming rewriting of application software or the need to throw away hardware.

Serial switched fabrics, however, brought a new computing paradigm to the market – a paradigm in which data transfer speeds from board to board were revolutionized. The potential for significantly increased processing throughput was enormously attractive.

For that potential to be realized, however, required a new kind of board connector – one capable of sustaining high bandwidth transfers – and this presented a challenge. Over a quarter of a century and more, connectors on VMEbus boards remained compatible: a board acquired twenty years ago could be simply withdrawn from the chassis/backplane and replaced with one of a modern vintage.

If VMEbus was to be able to take advantage of the advent of serial switched fabrics, the unthinkable had to happen. A new connector would need to be used. The connector selected was the MultiGig RT2 from Tyco – a 7-row, 16-wafer (wafers can be power, differential or single-ended) connector that delivers highly controlled impedance, minimal insertion loss and less than 3% crosstalk at transfer rates up to 6.25 Gbits/second. A 6U VPX board features six 16-column 7-row RT2 connectors and one 8-column 7-row RT2 connector, while a 3U board features two16-column 7-row RT2 connectors and one 8-column 7-row RT2 connector.

Fig. 1: VPX board section showing new connector, alignment/keying block

This new ‘flavor’ of VMEbus – which maintains compatibility with legacy application software even though it does not maintain the hardware compatibility that previous iterations of VMEbus had done – is VPX or, more officially, VITA 46. Since the first VPX products came to market in 2006, VPX has been – and continues to be – extraordinarily well received by customers whose applications demand cutting edge processing capability.

Particularly popular is VPX in its 3U form. The 3U form factor has assumed growing significance over the years as the space in which to house systems has become increasingly constrained, together with the need to minimize weight – in unmanned vehicles, for example, or man packs. 3U VMEbus suffered from important performance limitations – limitations which, it could be said, led to adoption of 3U CompactPCI in many programs. Now, however, 3U VPX offers the ability to pack significant processing capability and bandwidth into a small enclosure.

GE Fanuc Intelligent Platforms was the first company to announce 3U VPX products in the shape of the SBC340 single board computer, the GRA110 graphics board and the GBX410 Gigabit Ethernet switch. The company’s VPX product range now includes no fewer than eleven products. The 3U range features single board computers based on both Intel and PowerPC processors and a solid state storage module including 6U single board computers and multiprocessors, while the 6U VPX family offers both single board computing and multiprocessing. The MAGIC1 3U VPX Rugged Display Computer delivers unprecedented graphics performance, combining the Intel Core 2 Duo processor and the NVIDIA G73 in a single subsystem to deliver a solution capable of driving the most demanding visual applications.

While VPX may have created a small dislocation in the otherwise seamless VMEbus continuum, the substantial performance benefits it brings more than compensate for this. VPX also ensures that VMEbus is well positioned to continue to succeed over the coming quarter century.