The feature constraint

If you’re in a purely software business, your constraining resource is often (not always, not even necessarily in most cases, but often) the rate at which software gets changed. Well, specifically, the rate at which software gets changed in a direction your customers or potential customers are interested in. This means that the limiting factor on growth is likely to be rate at which you can add features or fixes that attract new customers, or maintain old customers.

It’s common to see business where this constraint is not understood throughout management, particularly manifesting in sales. In a business to business context, symptoms include:

  • sales teams close deals with promises of features that don’t exist, and can’t exist soon.
  • there’s no time to fix bugs or otherwise clean up because of the new feature backlog.
  • new features get added to the backlog based on the size of the requesting customer, not the cost/benefit of the customer.
  • the product roadmap is “what we said we’d have, to whom, by when”, not “what we will have”.

As Eliyahu Goldratt says, you have to subordinate the whole process to the constraint. That means incentivising people to sell something a lot like what you have now, over selling a bigger number of things you don’t have now and won’t have soon.

Immutable changes

The Fixed-Term Parliaments Act was supposed to bring about a culture change in the parliament and politics of the United Kingdom. Moving for the second reading of the bill that became this Act, Nick Clegg (then deputy prime minister, now member for Facebook Central) summarized that culture shift.

The Bill has a single, clear purpose: to introduce fixed-term Parliaments to the United Kingdom to remove the right of a Prime Minister to seek the Dissolution of Parliament for pure political gain. This simple constitutional innovation will none the less have a profound effect because for the first time in our history the timing of general elections will not be a plaything of Governments. There will be no more feverish speculation over the date of the next election, distracting politicians from getting on with running the country. Instead everyone will know how long a Parliament can be expected to last, bringing much greater stability to our political system. Crucially, if, for some reason, there is a need for Parliament to dissolve early, that will be up to the House of Commons to decide. Everyone knows the damage that is done when a Prime Minister dithers and hesitates over the election date, keeping the country guessing. We were subjected to that pantomime in 2007. All that happens is that the political parties end up in perpetual campaign mode, making it very difficult for Parliament to function effectively. The only way to stop that ever happening again is by the reforms contained in the Bill.

As we hammer out the detail of these reforms, I hope that we are all able to keep sight of the considerable consensus that already exists on the introduction of fixed-term Parliaments. They were in my party’s manifesto, they have been in Labour party manifestos since 1992, and although this was not an explicit Conservative election pledge, the Conservative manifesto did include a commitment to making the use of the royal prerogative subject to greater democratic control, ensuring that Parliament is properly involved in all big, national decisions—and there are few as big as the lifetime of Parliament and the frequency of general elections.

When a parliament is convened, the date of the next general election automatically gets scheduled for the first Thursday in May, five years out. The Commons could vote, with a qualified majority, to hold an election earlier, or an election would automatically be triggered if the government lost a no-confidence vote, but the prime minister cannot unilaterally declare an election date to suit their popularity with the franchise.

Observed behaviour shows that the Act has been followed to the letter, up to the current dissolution which required a specific change to the rules. Has the spirit of the Act, the motivation presented above, survived intact? The dates of elections since the Act passed were:

  • 7 May 2015, the first Thursday in May at the end of a five-ish-year Parliament, chosen to bring the existing behaviour into sync with the planned behaviour.
  • 8 June 2017, after a qualified majority vote within the terms of the Act.
  • 12 December 2019, after the aforementioned Early Parliamentary General Election Act.

The reason for the disparity is that the intended goal—a predictable release schedule that makes it easier for everyone involved to prepare—doesn’t match the cultural drivers. The desire to release when we’re ready, and have the features that we want to see, remains immutable, and means that even though we’ve adopted the new rules, we aren’t really playing by them.

I was tempted to hit “publish” at this point and leave the software engineering analogy unspoken. I powered on: here are a few examples I’ve seen where the rule changes have been imposed but the cultural support for the new rules hasn’t been nurtured.

  • Regular releases, but the release is “internal only” or completely unreleased until all of the planned features are ready;
  • Short sprints, where everything that has gone from development into QA is declared “done”;
  • Sprint commitments, where the team also describe “stretch goals” that are expected to be delivered;
  • Sustainable pace, where the “velocity” is expected to increase monotonically;
  • Self-organizing teams, where the manager feeds back on everybody’s status update at the daily stand-up;
  • Continuous integration, where the team can disable or skip tests that fail.

All of these can be achieved without the attached sabotage, but that requires more radical changes than adding a practice to the team’s menu. Radical, because you have to go to the root of why you’re doing what you do. Ask what you’re even trying to achieve by having a software team working on your software, then compare how well your existing practice and your proposed practice support that value. If the proposed practice is better, then adopt it, but there’s going to be a transition period where you continually explain why you’re adopting it, show the results, and (constructively, politely, and firmly) guide people toward acceptance of and commitment to the new practice. Otherwise you end up with a new fixed-term parliament starting whenever people feel like it.

On exploding boilers

Throughout our history, it has always been standardisation of components that has enabled creations of greater complexity.

This quote, from Simon Wardley’s finding a path, reminded me of the software industry’s relationship with interchangeable parts.

Brad Cox, in both Object-Oriented Programming: an Evolutionary Approach and Superdistribution, used physical manufacturing analogies (to integrated circuits, and to rifles) to invoke the concept of a “software industrial revolution” that would allow end users to assemble off-the-shelf parts to solve their problems. His “software ICs” built on ideas expressed at least as early as 1968 by Doug McIlroy. Joe Armstrong talked about a universal function registry, so that if someone writes sin/1 everybody else can use it.

Of course we have a lot of reusable components in software engineering now, and we can thank the Free Software movement at least as much as any paradigm of organising programming instructions. CTAN, CPAN, and later repositories act as the “component catalogues” that Cox discussed. If you want to make a computer do something, you can probably find an npm module or a Ruby gem that does most of the work for you. The vast majority of such components have free licenses, it’s rare to pay for a reusable component.

The extent to which they’re “standard parts”, on the model of interchangeable nuts and bolts or integrated circuits, is debatable. Let’s say that you download a package from the NPM. We know that you use it by calling require (or maybe import)…but what does that give you? An object? A constructor? A regular function? Does it run anything as a result of calling require? Does it work in your node/ionic/electron/etc. context? Is it even a lump of regular javascript, or is it a Real, or to have access to a JVM, or some other niche requirement?

Whatever these “standard parts” and however they’re used, you’re probably still doing a bunch of coding. These parts will do computery stuff, or maybe generic behaviour like authentication, date UIs, left-padding strings and the like. Usually we still have to develop ours apps as “engineered” software projects with significant levels of custom coding, to make those “standard parts” actually solve a useful problem. There are still people working for retail companies maintaining online store applications across the four corners of the globe, despite the fact that globes don’t have corners, these things all work the same way, and the risks associated with getting them wrong are significant.

Perhaps this is because software is a distinct thing, and we can never treat it like industrial product manufacturing.

Perhaps this is because our ambition always runs out ahead of our capability. Whatever we can reproducibly build, we’d like to be building something greater.

Perhaps this is because we’re still in the cottage industry stage, where we don’t yet know whether or how to standardise the parts, and occasionally the boilers explode.

Change

I was just discussing software architecture and next steps with a team building a tool to help analyse MRI images of brains. Most of the questions we asked explored ways to proceed by focussing on change:

  • what if the budget for that commercial component shows up? How would that change the system?
  • what if you find this data source isn’t good enough? How would you find that out?
  • which of these capabilities does the customer find most important? When will they change their minds?

that sort of thing.

We have all sorts of words for planning for, and mitigating the risk of, changes in low-level software design. In fact a book on building maintainable software talks about nothing else, because maintainable software is antifragile software.

But it happened that I wasn’t reading that book at the time, I was reading about high-level design and software architecture. The guide I was reading talked a lot about capturing the requirements and constraints in your software architecture, and this is all important stuff. If someone’s paying for your thing, you need to ensure it can do the things they’re paying for it to do. After all, they’re probably paying to be able to do the things that your software lets them do; they aren’t paying to have some software. Software isn’t real.

However, most of the reason your development will slow down once you’ve got that first version out of the door is that the world (which might be real) changes in ways that it’s hard to adapt your software to. Most of the reason you’re not adding new features is that you’re fixing bugs, i.e. changing the behaviour of the software from one that matches the flawed conception you had of what it should do to one that matches the flawed conception you now have of what it should do.

A good architecture should identify, localise, and separate sources of change in the software system. And then it should probably do whatever you think the customers think they want.

The value of the things on the left

With the rise of critical writing like Bertand Meyer’s Agile! The Good, the Hype, and the Ugly, Daniel Mezick’s Agile-Industrial Complex, and my own Fragile Manifesto, it’s easy to conclude the this Agile thing is getting tired. We’re comfortable enough now with the values and principles of the manifesto that, even if software has exited the perennial crisis, we still have problems, we’re willing to criticise our elders and betters rather than our own practices.

It’s perhaps hard to see from this distance, but the manifesto for Agile Software Development was revolutionary when it was published. Not, perhaps, among the people who had been “doing it and helping others to do it”.

Nor, indeed, would it have been seen as revolutionary to the people who were supposed to read it at the time. Of course we value working software over comprehensive documentation. Our three-stage signoff process for the functional specification before you even start writing any software is because we want working software. We need to control the software process so that non-working software doesn’t get made. Yes, of course working software is the primary measure of progress. The fact that we don’t know whether we have any working software until two thirds of the project duration is passed is just how good management works.

At one point, quite a few years after the manifesto was published and before everybody used the A-word to mean “the thing we do”, I worked at a company with a very Roycean waterfall process. The senior engineering management came from a hardware engineering background, where that approach to project management was popular and successful (and maybe helpful, but I’m not a hardware engineer). To those managers, Agile was an invitation for the inmates to take over the asylum.

Developers are notoriously fickle and hard to manage, and you want them to create their own self-organising team? Sounds like anarchy! We understand that you want to release a working increment every two to four weeks with a preference toward the shorter duration, but doesn’t that mean senior managers will spend their entire lives reviewing and signing off on functional specifications and test plans?

The managers who were open to new ideas were considering the Rational Unified Process, which by that time could be defined as Agile for the “nobody ever got fired for buying an IBM” crowd:

The Rational Unified Process. Image: wikimedia

That software engineering department now has different management and is Agile. They have releases at least every month (they already released daily, though those releases were of minimal scope). They respond to change rather than follow a plan (they already did this, though through hefty “change control” procedures). They meet daily to discuss progress (they already did this).

But, importantly, they do the things they do because it helps them release software, not because it helps them hit project milestones. The revolution really did land there.

Zen and the Art of Software Maintenance

In one part of the book Zen and the Art of Motorcycle Maintenance, which is neither about Zen nor motorcycle maintenance, there are two motorcycles and two riders. John Sutherland is a romanticist who appreciates the external qualities of his motorcycle: its aesthetics, and its use as a vehicle. The narrator is a classicist who appreciates the internal qualities of his motorcycle: its workings, parts, and mechanisms. When Sutherland has a problem with his bike he takes it to a mechanic. When the narrator does, he rationalises about the problem and attempts to discover a solution.

The book, which as its subtitle gives away is “an inquiry into values”, then follows the narrator’s exploration of a third way of considering quality that marries the romantic and classical notions holistically.

Now we come onto software. Software doesn’t exist. At some level, its abstractions and mathematics get translated into a sequence of states of an electronic machine that turns logic into procedure: but even that is a description that’s a few degrees abstracted from what software and computers really do.

Nonetheless, software has external and internal qualities. It has aesthetics and utility, and can be assessed romantically. A decidedly pedestrian word to describe the romanticist view of software is “requirements”, but it’s a common word in software engineering that means the right thing.

Software also has workings, parts, and mechanics. Words from software engineering to describe the classical view of software include architecture, design, clean code, SOLID…

…there are many more of these words! Unsurprisingly, the people who build software and who change software tend to take a classical view of the software, and have a lot more words to describe its internal qualities than its external qualities.

Typically, the people who are paying for software are interested in the romantic view. They want it to work to achieve some goal, and want someone else (us!) to care about what makes it work. Perhaps that’s why so many software teams phrase their requirements as “As a romantic, I want to task so that I can goal.”

Which is to say that making software professionally involves subordinating classical interpretations of quality to romantic interpretations. Which is not to say that a purely-classical viewpoint is unvaluable. It’s just a different thing from teaching a computer somersaults for a paying audience.

And maybe that subordination of our classical view to the customer/gold owner’s romantic view is the source of the principles:

Our highest priority is to satisfy the customer through early and continuous delivery of valuable software.

and:

Working software is the primary measure of progress.

In fact, this second one is not quite true. It suggests that you could somehow “count software”, and the more (working) software you’ve delivered, the better you’re doing. In fact, romanticism shows us that people only want software in that it enables some process or business opportunity, or makes it more efficient, or reduces errors, or lets them enjoy some downtime, or helps them achieve some other goal. So really progress toward that goal is the primary measure of progress, and working software is a leading metric that we hope tells us how we’re working toward that goal.

So all of those code quality and software architecture things are in support of the external view of the software, which is itself in support of some other, probably non-software-related, goal. And that’s why the cleanliness, or architectural niceness, or whatever classical quality, of the code is not absolute, but depends on how those qualities support the romantic qualities of the code.

Real life comes at you fast, though. When you’re working on version 1, you want to do as little work, as quickly as possible, to get to the point where you can validate that there are enough customers who derive enough value to make the product worthwhile. But by the time you come to work on version 1.0.1, you wish you’d taken the time to make version 1 maintainable and easy to change. Most subsequent versions are a little from column A and a little from column B, as you try new things and iterate on the things that worked.

As fast as possible, but no faster, I guess.

A question of focus

The problem with The Labrary is that I offer to do so many things – because I could do them, and do them well – that it can be hard to find the one thing I could do for you that would be most helpful:

  • Artificial Intelligence
  • Agile Development
  • Continuous Delivery
  • Software Architecture
  • Technical Writing
  • Developer Experience
  • Programmer Mentoring

Each of these supports the mission of “making it faster and easier to make high-quality software that respects privacy and freedom”, but all of them is overwhelming. I have credentials/experience to back up each of them, but probably don’t have the reputation as a general expert that someone like Dan North or Liz Keogh can use to have people ask me anything.

So I want to pick one. One thing, probably from that list, and pivot to focus on that. Or at least get in through the door that way, then have the conversations about the other things once you know how much faster and easier I make it for you to make high-quality software.

And I’d really value your suggestions. Which one thing do you know me for, above all others? Which one thing is the pain that the place you work, or places you’ve worked, most need fixing?

Comment here, have a chat, send an email. Thanks for helping me find out what I want to be when I grow up.

Great Documentation, Great Software

A paraphrased conversation, the other day, between me and a customer of one of my customers:

Me: Are you experienced at working with my customer’s developer APIs?

Them: I always feel like a newbie, because there’s so much stuff. But I always end up finding the docs I’m looking for.

Me: I’m writing the docs.

Them: Well, thanks! :D

Whether you’re writing developer APIs or graphical user interfaces, quality documentation that’s easy to find and use when needed is the best way to turn customers from novices who find the complexity offputting, to novices who know they’ll be able to tackle whatever’s coming their way.

Quality documentation is also useful for improving the quality of the software itself.

Docs-driven development

If you already know about test-driven development, you know that a benefit of TDD as a design tool is that it encourages you to think about your code from the perspective of how it will be used. Rather than implementing an algorithm then exposing an API that you hope will be useful, you design the API that helps solve the problem then implement an algorithm to support the use of that API.

Documentation is another tool for encouraging empathy in design. For every point you have to explain, you get to ask:

  • “why do I have to explain this?”

  • “Is there another way to design this such that I don’t need to tell people about this detail?”

  • “Is the thing that I’m telling people how to do, the thing that they would expect to want to do?”

Dev-driven documentation

The questions listed above can be most effectively answered if documentation is part of your iterative cycle of continuous improvement. Documentation can inform design and development, by pointing out cumbersome or difficult parts of the implementation. Development can inform documentation, by showing where the complexity lies and how to deal with it.

Documentation interacts with other activities, too. Test plans should ensure that they cover examples or walkthroughs from the documentation, so that you know the examples you’re giving to your customers actually work. Documenters should collaborate with testers to ensure a shared understanding of what the software is aiming to achieve.

Documents like API specifications, user manuals, or walkthrough videos should be versioned and built alongside the corresponding versions of the software.

Working software over comprehensive documentation

Throughout these activities, the point is not to generate documentation for its own sake. One office I worked in had a shelf containing several feet of documentation for a UNIX system that I never opened: the online documentation and a couple of cookbook-style books were sufficient.

The reason for putting effort into your software’s documentation is that this effort yields improvements in the software. A more empathetic design, a better-tested implementation, and more confident customers are all steps on the path to higher-quality software, easier and faster. And of course, the Labrary can help you with that.

Solving the underlying problem

As a software engineer, it’s easy to get work engineering software. Well, maybe not easy, but relatively so: that is the kind of work that comes along most. The kind of work that people are confident I can do. That they can’t do, so would like me to do for money.

It’s also usually the worst work available.

I don’t want to take your shopping list of features, give you a date and a cost, then make those features. Neither of us will be very happy, even if it goes well.

I want to get an understanding of your problem, and demonstrate how software can help in solving it. Maybe what we need to understand isn’t the problem you presented, but the worse problem that wasn’t on your mind. Or the opportunity that’s worth more than a solution to either problem.

Perhaps we ask a question, in solving your problem, to which the answer is that we don’t know, and now we have another problem.

You might not need me to build all of the features you thought of, just one of them. Perhaps that one works better if we don’t build it, but configure something that already exists. Or make it out of paper.

You understand your problem and its domain very well. I understand software very well. Let’s work together on combining that expertise, and both be happier in the process.