Principles of software development revisited

BeachSpainLite-2017-08-15-10-04.jpg

Summer… my traditional time for doing all that stuff that requires a chunk of time… erh… OK, “projects” – only they aren’t well planned and they only resemble projects in the rear-view mirror.

Why now? Why summer? – Because my clients are on holiday too so I’m quiet and not delivering much in the way of (agile) training or consulting. Because my family is away visiting more family. Thus I have a chunk of time.

This year’s projects include some programming – fixing up my own Twitter/LinkedIn/Facebook scheduler “CloudPoster” and some work on my Mimas conference review system in preparation for Agile on the Beach 2018 speaker submissions.

But the big project is a website rebuild.

You may have noticed this blog has moved from Blogger to a new WordPress site, and attentive readers will have noticed that my other sites, allankelly.net and SoftwareStrategy.co.uk have also folded in here. This has involved a lot of content moving, which also means I’ve been seeing articles I’d forgotten about.

In particular there is a group of “The Nature of Agile” articles from 2013 which were once intended to go into a book. Looking at them now I think they still stand, mostly. In particular I’m impressed by my 2013 Principles of Software Development.

I’ll let you can read the whole article but here are the headlines:

Software Development Principles

  1. Software Development exhibits Diseconomies of Scale
  2. Quality is essential – quality makes all things possible
  3. Software Development is not a production line

Agile Software Principles

  1. Highly adaptable over highly adapted
  2. Piecemeal Growth – Start small, get something that works, grow
  3. Need to think
  4. Need to unlearn
  5. Feedback: getting and using
  6. People closest to the work make decisions
  7. Know your schedule, fit work to the schedule not schedule to work
  8. Some Agile practices will fix you, others will help you see and help you fix yourself

The article then goes on to discuss The Iron Triangle and Conway’s Law.

I think that essay might be the first time I wrote about diseconomies of scale. Something else I learned when I moved all my content to this new site is that the Diseconomies of Scale blog entry is by far my most read blog entry ever.

I’m not sure if I’m surprised or shocked that now, four years later, these still look good to me. I really wouldn’t change them much. In fact these ideas are all part of my latest book Continuous Digital.

I’m even starting to wonder if I should role those Nature of Agile essays together in another book – but thats bad of me! Too many books….

Join Allan Kelly’s mailing list to get free updates on blog post, insights and events.

Programmer’s Rorschach test

The picture above, I recently added this picture to Continuous Digital for a discussion of teams. When you look at it what do you see:

An old style structure chart, or an organization chart?

It could be either and anyone who knows of Conway’s Law shouldn’t be surprised.

When I was taught Modula-2 at college these sort of structure charts were considered superior to the older flow charts. This is functional decomposition, take a problem, break it down to smaller parts and implement them.

And that is the same idea behind traditional hierarchical organizational structure. An executive heads a division, he has a number of managers under him who manage work, each one of these manage several people who actually do the work (or perhaps manage more manager who manage the people who do the work!)

Most organizations are still set up this way. It is probably unsurprising that 50 years ago computer programmers copied this model when designing their systems – Conway’s Law, the system is a copy of the organization.

Fast forward to today, we use object oriented languages and design but most of our organizations are still constrained by hierarchical structure, that creates a conflict. The company is structurally decomposed but our code is object oriented.

The result is conflict and in many cases the organization wins – who hasn’t seen an object oriented system that is designed in layers?

While the conflict exists both system and organization under perform because time and energy are spent living the conflict, managing the conflict, overcoming the conflict.

What would the object-oriented company look like?

If we accept that object oriented design and programming are superior to procedural programming (and in general I do although I miss Modula-2) then it becomes necessary to change the organization to match the software design – reverse Conway’s Law or Yawnoc. That means we need teams which look and behave like objects:

  • Teams are highly cohesive (staffed with various skills) and lightly coupled (dependencies are minimised and the team take responsibility)
  • Teams are responsible for a discrete part of the system end-to-end
  • Teams add value in their own right
  • Teams are free to vary organizational implementation behind well defined interface
  • Teams are tested, debugged and maintained: they have been through the storming phase, are now performing and are kept together

There are probably some more attributes I could add here, please make your own suggestions in the comments below.

To regular readers this should all sound familiar, I’ve been exposing these ideas for a while, they draw on software design and Amoeba management, I discuss them at greater length Xanpan, The Xanpan Appendix and now Continuous Digital – actually, Continuous Digital directly updates some chapters from the Appendix.

And like so many programmers have found over the years, classes which are named “Manager” are more than likely poorly named and poorly designed. Manager is a catch all name, the class might well be doing something very useful but it can be named better. If it isn’t doing anything useful, then maybe it should be refactored into something that is. Most likely the ManagerClass is doing a lot of useful stuff but it is far from clear that it all belongs together. (See the management mini-series.)

Sometimes managers or manager classes  make sense, however both deserve closer examination. Are they vestige from the hierarchal world? Do they perform specialist functions which could be packaged and named better? Perhaps they are necessary, perhaps they are necessary for smoothing the conflict between the hierarchal organization and object oriented world.

Transaction costs can explain both managers and manager classes. There are various tasks which require knowledge of other tasks, or access to the same data. It is cheaper, and perhaps simpler, to put these diverse things together rather than pay the cost of spreading access out.

Of course if you accept the symbiosis of organization and code design then one should ask: what should the organization look like when the code is functional? What does the Lisp, Clojure or F# organization look like?

And, for that matter, what does the organization look like when you program in Prolog? What does a declarative organization look like?

Finally, I was about to ask about SQL, what does the relational organization look like, but I think you’ve already guessed the answer to this one: a matrix, probably a dysfunctional matrix.