Tag Archives: computing

Software Pottery

“Building software” is a phrase I hear used time and again. Indeed, many do still think of software development as akin to construction.  Modern (agile) software development doesn’t feel like that to me. There was a time, like the construction architect, when we had to increment and iterate on paper and in models. The cost of computing was too high to do such iteration inside the machine. The cost difference between making a small change in our understanding and reflecting that in the actual product was too great. The cost of change meant that we had to treat the creation of software like constructing buildings or bridges. But those times are, or should be, in the past.

To me, modern (agile) software development feels more like pottery. But, instead of ‘throwing clay’ we throw our consciousness, in the form of electrons flowing over silicon, onto a spinning wheel of user-story implementation cycles.

Picture of a pot being created and evolved on a pottery wheel.
Source: http://www.flickr.com/photos/kellinahandbasket/2183799236

We evolve our understanding of what our customer wants with each conversation. We reflect that understanding by evolving the product’s shape as we touch the outer surface with each new automated acceptance test (or example scenario). We evolve its structure as we touch the inner surface with each new unit test (or unit specification). We keep it supple as we moisten it with each refactoring. Our customer looks on, gives us feedback and we start the next revolution of the software development wheel. Never letting the product dry and harden; keeping it flexible, malleable, soft(ware).

There is nothing that feels like construction here. I never feel like I’m “building” something. Much more like I’m evolving my understanding, evolving the product, evolving my understanding again and so on.

For these reasons l am not comfortable with referring to this process as “building”. I’m also not comfortable calling it “throwing” (as in pottery).

I am very comfortable calling it “development”. I use the word “develop” in terms of its literal meaning:

to bring into being or activity; generate; evolve.

From the first thought of a new idea, through each conversation along the way, to each revolution of the software development wheel, I develop products.

I don’t “build”.

I create. I make. I shape. I evolve.

Footnote: I’m not aware of anyone drawing this analogy before. If you have heard or read someone explain it in this way before now, please let me know.

Monsters, Names, Pot-Roast & The Waterfall Model

“Antony” (without the ‘H’) is the anglicised version of Antonius. In victorian times (there or thereabouts I’m guessing), among those wishing to appear oh so intelligent, gossip spread that the spelling of “Antony” was wrong… For, so they would say, it is born of the greek word “anthos” (meaning “flower”) – oh dear… so many poor children with misspelt names… 

Despite being completely wrong, the world forgot of my name’s etruscan origin and spelt it with an ‘H’… This misinformation established itself through the eras so much so that, today, the de-facto spelling is “Anthony”. It has even found it’s way into the American pronunciation of the name as: “An-thon-ee”.

Waterfall development has something in common with this story… somehow, through misinformation, what it once was has been warped, into something else.

The key difference is that Waterfall is now increasingly represented as was originally intended. Unfortunately for me, my name is not…


Monsters & Legends

Some might think that the Waterfall Model is an approach to software development, first explained (but not named) in Winston Royce’s 1970 Paper “Managing the Development of Large Software Systems” (PDF), but they could be wrong…

Somehow, it seems to have become something else… it became the way (many) people thought software should be developed… the norm for software ‘professionals’. Years of anecdotal failure followed and Waterfall became a legend – told time and again much like a scary camp-fire story… The enemy of effective software development… A monster that will consume all the resources it can, spewing out nothing but documentation, rarely concluding in working software – at best 20% of the time.

This negative view, to what was once the de-facto approach to software development, is actually far closer to Royce’s original words on Waterfall than many seem to know…


The Truth & Technology

In Royce’s original paper, he shows a progression of activities, that came to be known as the waterfall model.

What we rarely hear of is Royce’s original words on the subject:

“…the implementation described above is risky and invites failure.”

Further to this, Royce goes on to explain that the reason that this cannot work is because there are too many things we cannot analyse up-front:

“The testing phase which occurs at the end of the development cycle is the first event for which timing, storage, input/output transfers, etc., are experienced as distinguished from analyzed. These phenomena are not precisely analyzable. They are not the solutions to the standard partial differential equations of mathematical physics for instance.”

He explains that we need feedback loops. He goes on to warn of (a conservative) 100% overrun in schedule and costs:

“…invariably a major redesign is required. A simple octal patch or redo of some isolated code will not fix these kinds of difficulties. The required design changes are likely to be so disruptive that the software requirements upon which the design is based and which provides the rationale for everything are violated. Either the requirements must be modified, or a substantial change in the design is required. In effect the development process has returned to the origin and one can expect up to a 100-percent overrun in schedule and/or costs.”

Some of Royce’s strategies, like “Involve the customer” and obtaining early feedback, have lived on in modern (Agile) methodologies. Beyond that, we should remember that his specific recommendations on how to solve the problems of a waterfall model were all based on the technology of the time.


Pot-Roast & The Cost of Change

In 1970, computing was much more expensive than it is today. In those days, changing software was far more expensive than changing pictures and words on paper. It was also much harder to express your design in a human-friendly way in the programming languages of that time. As a result of these and other factors, documentation was a major part of how Royce tried to solve the inherent problems of the Waterfall model.


Technology, tools & thinking have moved on and our documentation no longer needs to be static. It lives. It can breath. The specification can automatically verify that the implementation does what we said it should do (e.g. as in BDD Specs or ATDD/TDD Tests). Modern programming languages allow us to express the design and our understanding of the domain far more clearly, negating the need to first detail our thoughts on paper in natural language. We simply don’t have to cut the ends off that pot-roast anymore.


Only now, at the end…

Waterfall, thanks to the popularity of Agile, has gone from something I was shown at school as “how software is developed” to being seen in the light that it was originally presented – how software should not be implemented.

This is despite those who still profess the legitimacy of Waterfall and those still shocked and surprised when they hear of Royce’s own words against the monster he unintentionally created.

As for my name, I hold out little hope for change. I doubt that the world will use my name as it was originally intended and so I have resigned myself to needing two domain names… one with an ‘H’ in it, and the correct one without – I wonder which one brought you here.