Maintainability and Serviceability are Design Considerations Too

June 16, 2016

Max The Magnificent-June 16, 2016

I don’t know about you, but I hate sitting in the car at a junction waiting for another car to pass, only for it to slow down and turn at the last moment without the driver giving any indication as to his or her intentions.

I remember driving with my son shortly after he'd got his license. I chastised him when he made a turn without indicating. He replied that he'd checked the rear view mirror to see if anyone was there, and then made the conscious decision to not use his indicator based on the fact that there was no one around to see it.

While admiring the speed of his excuse response, I explained that there's an overhead involved in checking one's surroundings and making a decision as to whether or not to indicate. Why not always indicate, irrespective of whether there is anyone to see it or not?

I fall at the other end of the indicating spectrum. I use my indicators automatically without thinking. I even find myself indicating a right-turn into my garage from my drive, but at least everyone around me knows what I'm planning on doing... or so I thought.

The reason I'm waffling on about this here is that, while driving into work this morning, I slowed to turn right at a junction, only to see the driver of a car waiting at that junction gesticulating angrily in a "Why didn’t you indicate, you moron?" fashion. I responded with some gesticulations of my own (trying, of course, to explain that I was indeed indicating).

The way I remember things working in the good old days when I was a lad is that, when an indicator bulb failed, the click of the relay inside the cab increased in frequency, thereby warning you that something was awry. It seems this is no longer the case -- at least in regard to my 2006 Dodge Ram 1500.

Anyway, the long and the short of it is that I pulled over and got out of the truck to check my lights, only to discover that the front-right indicator bulb had indeed gone to meet its maker, as it were. Thus, my next stop was at AutoZone, where I picked up a pack of two replacement bulbs. With a cheery whistle on my lips, I then popped open the bonnet (i.e., the "hood" for non-English-speaking Americans) intending to swap out the bulb.

Sad to relate, my mood quickly turned to one of doom and gloom when I realized that there was no obvious way to access the indicator assembly. The following image is about as good as it got.

(Source: Max Maxfield /

Another thing I remember from the days of yore was that it was relatively easy to swap out light bulbs in cars. It seems to me that the designers of yesteryear put some thought into creating their lighting assemblies and mounting them in such a way that you could quickly and easily access any errant components and exchange them for working counterparts.

By comparison, I fear that today's designers no longer feel constrained to consider how the "man in the street" (especially the one wearing the cool Hawaiian shirt) will maintain and service their creations.

Honestly, this just about brought me to my knees -- a situation that was only exacerbated by the fact that I was wearing shorts. Thank goodness for YouTube is all I can say, along with my gratitude for all the folks who put up videos showing how to do this sort of thing. Suffice it to say that swapping the bulb required an inordinate amount of effort involving locating and removing multiple screws hidden in strange and unusual places, and then wrestling the entire light assembly out of the vehicle.

I don’t think the designers of this vehicle could have made this task harder if doing so had been part of the original design requirements and specification.

Thankfully I'm not bitter. (Sadly, I'm not a very good liar.)

Unfortunately, the same problems often raise their ugly heads in embedded systems -- designers focus on things like power consumption and performance inside, and making the system look shiny and tasty outside, but they don’t spend as much effort as they perhaps should addressing how the system will be maintained and serviced once it's been dispatched to roam wild and free in the big wide world.

What I really like is to see a system that doesn’t just look good when you take it out of the box, but that is easy to service and maintain over the course of its life. As an example, my office is in a building owned by MaxVision, Rugged Portable Computers. The folks at MaxVision (no relation) specialize in making ruggedized, transportable, extreme-performance workstations for use in the harshest environments. For example, the image below is of a MaxPac 8261 XLRA.

(Source: MaxVision)

This little beauty boasts dual Xeon processors (up to 18 cores per processor), triple 24" screens, up to 1TB of main memory, quad data disks providing up to 24TB of removable RAID data storage, and dual removable SSD system disks. These systems have been designed from the ground up with serviceability and maintenance in mind. For example, using your fingers to unscrew two knurled nuts allows you to remove the quad data disk caddy in a matter of seconds.

(Source: MaxVision)

In addition to maintenance, this capability is also useful in situations that require you to protect the contents of your data disks by removing them and locking them in a safe at night, or by completely destroying them if the situation demands (some users might literally have only a matter of seconds to secure their data in certain circumstances).

Observe also the four additional knurled nuts -- one per drive -- in the above image. Unscrewing these nuts allows their associated drives to be quickly and easily removed from the caddy.

The dual system disks have their own removable caddy (not seen in the image above). Similarly, the optical drive can be accessed and swapped out within a matter of seconds without having to open the main cabinet. Furthermore, individual screens or the entire display assembly can be quickly and easily swapped out as the occasion demands.

(Source: MaxVision)

I know the guys at MaxVision pretty well (they kindly include me in their Thanksgiving and Christmas celebrations and the occasional summer barbecue), and I often see their hardware, power supply, and mechanical designers in the conference room looking at exploded views of a new system on a big display screen discussing every detail down to the types, sizes, materials, and locations of each screw. It's this attention to detail that separates real-world systems from wannabes.

It strikes me that the folks who designed my Dodge Ram 1500 could take some lessons from the guys and gals at MaxVision (but, once again, I'm not bitter).

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