What does "surface area for technical and functional debt" mean in the following context?

Question

What does "surface area for technical and functional debt" mean in the following context? I know what technical and functional debt means, but I don't understand what surface area for technical and functional debt means in the following context. As far as I know, the surface area is literally the outside of something or sometimes something superficial:

As we saw in the last chapter, an IT leader’s goal is to groom the EA asset to enhance its flexibility and agility. The leaner the asset is, the more flexible it will be. We don’t want to carry extra baggage in our asset—it adds weight that makes it harder to roll. It presents more surface area for technical and functional debt. It has more defects.

Answer 1

The term surface area comes from mathematics

Surface area is the measure of how much exposed area a solid object has, expressed in square units.

but was adopted by many other domains. For example, it's commonly used in computing to describe the resources of a system that are accessible from the outside and thus vulnerable (might be attacked).

Disabling network access to unused ports reduces surface area.

In your sentence, surface area could refer to all exposed parts of the asset (e.g. all software features given to the customer). The more this area grows, the more resources are required to maintain/enhance it.

Answer 2

It seems to be a metaphorical use of 'surface area'.

Surface area is literally the area (length multiplied by width) of a flat surface. Whereas three dimensions are usually considered for things like furniture, the top of a table, or floor space are considered to have a 'surface area' on which things can be placed.

In your example, 'surface area' is being used in a similar way that "room" is used metaphorically - that there is more opportunity for something to happen. In this case, it suggests that a particular course of action with EA assets results in there being more 'room' for problems ("technical and functional debt") to occur or exist.

Answer 3

The surface area of an object is its outside, its exposed part. In this metaphor it is seen as the part which may be attacked by something, the "technical and functional debt".

The irony of this metaphor is that in making something geometrically "leaner" ie thinner, its content is reduced more quickly than its surface area, so the ratio of surface area to content increases.

Answer 4

Behold! an absolutely terrible mixed metaphor, demonstrating precisely why you shouldn't do that. I cannot fathom what is meant to be represented by the surface area of a fat, unflexible, heavy, poorly rolling, defective "asset." It also seems to conflate weight and surface area, which aren't even proportional.

Right from the start, I would suggest you abandon all hope of ever understanding this word soup of a sentence. In technical jargon, the "surface area" of a product is the part of the product that is exposed to the outside world, and therefore could be vulnerable to an attack.

Technical debt, meanwhile, is the concept that as a product gets more features, components that made sense initially can become overloaded or too complex to maintain. It is a natural part of product evolution, and is eliminated by redesigning parts of the product to work more effectively and robustly.

Functional debt, while not a term that I'm familiar with, likely represents the concept that there are more desirable features to add to the product than there is time to add them, or perhaps that customer demands outpace the means of the producer to meet them. This is not a normal part of product evolution and would be indicative of needing to invest more resources in the product.

I have never heard of "surface area of technical debt," and the concept doesn't make sense because technical debt is not something introduced into the product from the outside world. Technical debt is more reasonably compared to a volume than to a surface area.

"Surface area of functional debt" is similarly nonsensical, since functional debt (I assume) is characterized by features not part of the product. Thus, the design and implementation of the product is wholly irrelevant to the accrual (or not) of so-called "functional debt."

I am very suspicious that perhaps the author of this paragraph really has nothing meaningful to say and is attempting to hide that fact behind syllogisms and jargon, and if they're trying to sell you something, run away.

TL;DR: The only person on Earth who knows what this phrase is supposed to mean is its author, and if they didn't explain it, nobody else can.