PC/104: The small form factor doing big things

Writing about can be challenging: If you’re just talking about the form factor, there’s not a whole lot of new material to cover. In fact, if you’re reading this in a printed magazine, it’s likely that you already know about PC/104. But for the sake of those who don’t know – if you’re a young engineer, or if you’re the equivalent of that one person who hasn’t seen that classic movie (“Wait... you’ve never seen XYZ??”) – for the sake of the new folks, here’s the recap:

PC/104 has been around since the early 1990s. It specifies a particularly rugged, almost square circuit board size with designated corner-mounting holes. There are predetermined locations for stackable connectors that carry various buses: ISA, PCI, and PCI Express.

A benefit of this form factor is that it enables many different configuration options. With it, single-board computers can combine with power supplies, networking ­modules, data-acquisition cards, and a wide variety of specialty modules. Some companies who build to the PC/104 standard specialize in particular types of products such as CPUs, , or serial cards, while other companies build products that run the entire gamut.

So PC/104’s benefit? You can mix and match. You can tailor a system with exactly the modules you need. SWaP? You bet: PC/104 systems work well in scenarios where size, weight, and power need to be optimized.

Here’s the thing: PC/104 (the form factor) has been around a long time. It is proven. Countless critical embedded systems have been successfully fielded; these systems are supporting transportation, defense, communications, industrial, security, and research programs around the globe and in space.

What’s more, the leading PC/104 manufacturers are continually developing new ­products to support the latest needs in the embedded marketspace.

I’ve been talking to embedded systems engineers who design with PC/104, plus to some hardware engineers who build PC/104 modules. I wanted to know: Why PC/104? Why choose it? Why has the form factor endured? Following are some of the answers I got:

I have a colleague who has been using PC/104 for a long time. This is a common theme. Some program managers and systems developers have been using the PC/104 form factor for their entire careers. When you find a platform that works well, it’s a good bet that you’ll use it again in the future.

There are a lot of boards on the market, so we have a lot of options. This is also true. There are a lot of PC/104 modules out there. Many are new – advanced single-board CPUs, Ethernet switches, DSPs, – but many others are legacy-based. That is, even as new PC/104-based modules are announced every quarter, most PC/104 manufacturers plan for strategic inventory; they can support products for seven, ten, sometimes 15 years or more. For programs that take years to develop and are expected to be fielded for many years beyond that, PC/104 is an excellent choice.

It’s a good balance between size and power. For its size, PC/104 can deliver exceptional performance. It hits a sweet spot where other form factors can sometimes fall short, namely IoT and IIoT. (You can’t write a column these days without mentioning the industrial Internet of Things, so this is a good place to fulfill my duty. Actually, PC/104 is stepping up when it comes to IoT, edge computing, and fog computing.)

PC/104 performs well in rugged environments. Of course, there are a range of products on the market. Some are extended temperature, some are not. Some are optimized for shock and vibration, some are not. But if you want to build a robust system that can handle -40 °C to +85 °C temperatures while bolted to the side of an excavator in the middle of the desert, PC/104 lets you do that. If you want to configure a system that can work reliably while tucked behind the driver’s seat of an industrial agriculture rig, you can do that too. The products are out there. Thanks to dozens of PC/104 manufacturers, and some stellar enclosure designs, there are countless systems with PC/104 guts making the industrial, defense, and communications world go ‘round.

A call to collaboration and action

members and PC/104 manufacturers: Let’s work together: Get involved with the Technical Committee and/or participate in the Marketing Committees. Our working groups include some great industry minds, and they are always eager to welcome new collaborators. For more information on PC/104, check out www.pc104.org or drop us a line at info@pc104.org.

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