When Apple first unveiled the Mac Mini some months ago, WireSpring was inundated with requests to port our Linux-based kiosk and digital signage software to that platform.  The impossibly cute form factor (hyped by classic Apple marketing shtick) was difficult for many geeks-cum-systems integrators to resist, and several Mac software companies came out right away pledging support for the Mini.  We brought one in to investigate, but in the end decided to stick with our x86-based system for the time being (which looks like it was the right choice, since Apple just announced that it will soon switch to regular Intel chips).

For the most part, people understood why we were hesitant to port our software to a different hardware platform -- but they continued to come to us for recommendations on small form factor computers to use in their self-service kiosk systems and digital signage networks.  Some frequently cited examples were those from Sumicom or this very newly announced Mini-clone from AOpen.  Yes, these systems are cute, but here is the lowdown on what we find when we crack one of them open (including the Mac Mini):

   
• Consumer grade 3.5" or 2.5" low-RPM hard disk
   
• Custom form-factor motherboard
   
• Integrated AGP video using shared system RAM
   
• Low-wattage power supply, typically with a proprietary external power brick
   
• Lots and lots of heat

Hmm... where to start.  Ok, from the top.  First, the hard disk is still the item in your computer that is most likely to fail, and sadly it's the first place that both the Mac Mini and most of the mini PCs skimp on in order reach that low, consumer-friendly price point.  I've mentioned in past articles that we recommend high-reliability Western Digital drives that feature longer warranties and use better parts.  The new darling is the Western Digital Raptor SATA series, which uses 10,000 RPM SCSI disk internals and boasts an amazing 1.2 million hour MTBF (mean time between failure) and a 5 year warranty.  They're not cheap, but our experiences with them have been very positive so far.

My next gripe about these tiny PCs is their custom form factor motherboards.  Since nothing that gets mass-produced will fit into these tiny enclosures, manufacturers must design, test, build and maintain their own motherboards for each unit that they release.  On top of that, it also means that if the motherboard fails for some reason, you can't just pop in a replacement from CompUSA, you have to go and get another motherboard from the manufacturer, if they'll even sell you one.  In our experience, it's much better to use a case that will accommodate a standard sized motherboard.  Micro ATX boards are less than 10" on a side, and can more or less be swapped out for one another.  If you need something really small, get a system built around a mini-ITX board, which is about 6" on a side.

While I have nothing against integrated AGP video per se, it can't match the power or flexibility of a good video card from Matrox, ATI or Nvidia, not to mention that add-in cards often provide other goodies like HD support, widescreen resolutions, portrait mode/rotation, and even multi-monitor support.  And since you can't fit a video card into most of the small form factor machines out there right now, you also can't add things like TV tuners or live video input.

I think the most overlooked part of any computer is the power supply, and unfortunately we've found that most manufacturers overlook them as well.  We've come across far too many cheap, underpowered units that don't supply clean power.  When companies like Sparkle can produce extremely high-quality 1U server power supplies at just about any wattage you like, why skimp?  I'm also not a fan of designs that require external power bricks, since that's just one more thing to get lost, jostled, unplugged, exchanged for a different part, etc.

Finally, there's one last factor to consider when deciding between a small machine and a really small one: heat.  The hard disk, CPU, RAM, power supply, and even components on the motherboard all radiate heat.  Squishing them together inside a tiny case is a recipe for disaster, as even a few degrees rise in ambient temperature can reduce the expected lifetime of the computer's components dramatically.  Even if a small PC runs nicely for 8 hours at a time, things are likely to be much different when it's running 24/7.  Spread things out a bit, add some ventilation and a few well-placed brushless fans, and you've just increased the stability, reliability and life expectancy of your system.  While we're on this topic, just because a system is fanless doesn't mean that it's going to run cool inside.  In fact, many fanless systems operate at temperatures that are just low enough not to cause an immediate failure, but this additional heat will reduce the lifespan quite a bit.

On your desktop, in your living room, or in a place where they don't have to run 24/7, small form factor machines like the Mac Mini and assorted clones can be great.  They're attractive, unobtrusive and powerful enough to do just about everything that a typical computer user does.  But when your systems are deployed to remote locations and require solid 24/7 operation, there are many better choices.  Whether you build your own system using the recommendations above, or purchase a pre-configured digital signage appliance, choosing the right hardware platform will yield higher uptime, reduced service calls, and greater profits for your kiosk or signage network.