To build and to maintain

I had the opportunity to visit another country recently (which one doesn't matter) and I enjoyed the warmer climate and the food. I also had the opportunity to observe another country's practices for building and maintaining houses, office buildings, roads, bridges, and other things.

The United States is pretty good at building things (roads, bridges, buildings, and such) and also good at maintaining them. The quality of construction and the practices for maintenance vary, of course, and overall governments and large corporations are better at them than small companies or individuals.

In the country I visited, the level of maintenance was lower. The culture of the country is such that people in the country are good at building things, but less concerned with maintaining them. This was apparent in things like signs in public parks: once installed they were left exposed to the elements where they faded and broke in the sun and wind.

My point is not to criticize the country or its culture, but to observe that maintaining something is quite different from building it.

That difference also applies to software. The practices of maintaining software are different from the practices of constructing software.

Software does not wear or erode like physical objects. Buildings expand and contract, develop leaks, and suffer damage. Software, stored in bits, does not expand and contract. It does not develop leaks (memory leaks aside), It is impervious to wind, rain, and fire. So why do I say that software needs maintenance?

I can make two arguments for maintenance of software. The first argument is a cyber-world analog of damage: The technology platform changes, and sometimes the software must change to adapt. A Windows application, for example, may have been designed for one version of Windows. Windows, though, is not a permanent platform; Microsoft releases new versions with new capabilities and other changes. While Microsoft makes a considerable effort to maintain compatibility, there are times when changes are necessary. Thus, maintenance is required.

The second argument is less direct, but perhaps more persuasive. The purpose of maintenance (for software) is to ensure that the software continues to run, possibly with other enhancements or changes. Yet software, when initially built, can be assembled via shortcuts and poor implementations -- what we commonly call "technical debt". Often, those choices were made to allow for rapid delivery.

Once the software is "complete" -- or at least functional, maintenance can be the act of reducing technical debt, with the goal of allowing future changes to be made quickly and reliably. This is not the traditional meaning of maintenance for software, yet it seems to correspond well with the maintenance of "real world" objects such as automobiles and houses. Maintenance is work performed to keep the object running.

If we accept this definition of maintenance for software, then we have a closer alignment of software with real-world objects. It also provides a purpose for maintenance; to ensure the long-term viability of the software.

Let's go back to the notions of building and maintaining. They are very different, as anyone who has maintained software (or a house, or an automobile).

Building a thing (software or otherwise) requires a certain set of skills and experience.

Maintaining that thing requires a different set of skills and experience. Which probably means that the work for maintenance needs a different set of management techniques, and a different set of measurements.

And building a thing in such a way that it can be maintained requires yet another set of skills and experience. And that implies yet another set of management techniques and measurements.

All of this may be intuitively obvious (like solutions to certain mathematics problems were intuitively obvious to my professors). Or perhaps not obvious (like solutions to certain math problems were to me). In either case, I think it is worth considering.