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PAYGO II

June 12, 2010 4 comments

PAYGO stands for “Pay As You Go“. It’s the name of the personal process that I use to create or maintain software. There are five operational states in PAYGO:

  • Design A Little
  • Code A Little
  • Test A Little
  • Document A Little
  • Done For Now

Yes, the fourth state is called “Document A Little“, and it’s a first class citizen in the PAYGO process. Whatever process you use, if some sort of documentation activity is not an integral part of it, then you might be an incomplete and one dimensional engineer, no?

“…documentation is a love letter that you write to your future self.” – Damian Conway

The UML state transition diagram below models the PAYGO states of operation along with the transitions between them. Even though the diagram indicates that the initial entry into the cyclical and iterative PAYGO process lands on the “Design A Little” state of activity, any state can be the point of entry into the process. Once you’re immersed in the process, you don’t kick out into the “Done For Now” state until your first successful product handoff occurs. Here, successful means that the receiver of your work, be it an end user or a tester or another programmer, is happy with the result. How do you know when that is the case? Ask.

Notice the plethora of transition arcs in the diagram (the green ones are intended to annotate feedback learning loops as opposed to sequential forward movements). Any state can transition into any other state and there is no fixed, well defined set of conditions that need to be satisfied before making any state-to-state leap. The process is fully under your control and you freely choose to move from state to state as “God” (for lack of a better word) uses you as an instrument of creation. If clueless STSJ PWCE BMs issue mindless commands from on high like “pens down” and “no more bug fixing, you’re only allowed to write new code“, you fake it as best you can to avoid punishment and you go where your spirit takes you. If you get caught faking it and get fired, then uh….. soothe your conscience by blaming me.

The following quote in “The C++ Programming Language” by mentor-from-afar Bjarne Stroustrup triggered this blog post:

In the early years, there was no C++ paper design; design, documentation, and implementation went on simultaneously. There was no “C++ project” either, or a “C++ design committee.” Throughout, C++ evolved to cope with problems encountered by users and as a result of discussions between my friends, my colleagues, and me. – Bjarne Stroustrup

When I read it on my Nth excursion through the book (you’ve made multiple trips through the BS book  too, no?), it occurred to me that my man Bjarne uses PAYGO too.

Say STFU to all the mindlessly mechanistic processes from highly-credentialed and well-intentioned luminaries like Watts Humphrey’s PSP (because he wants you to transform into an accountant) and your mandated committee corpo process group (because the chances are that the dudes who wrote it haven’t written software in decades) and the TDD know-it-alls. Embrace what you discover is the best personal development process for you; be it PAYGO or whatever personal process the universe compels you to do. Out of curiosity, what process do you use?

If you’re interested in a higher level overview of the personal PAYGO process in the context of other development processes, you can check out this previous post: PAYGO I. And thanks for listening.

Leverage Point

April 11, 2010 Leave a comment

In this terrific systems article pointed out to me by Byron Davies, Donella Meadows states:

Physical structure is crucial in a system, but the leverage point is in proper design in the first place. After the structure is built, the leverage is in understanding its limitations and bottlenecks and refraining from fluctuations or expansions that strain its capacity.

The first sentence doesn’t tell me anything new, but the second one does. Many systems, especially big software systems foisted upon maintenance teams after they’re hatched to the customer, are not thoroughly understood by many, if any, of the original members of the development team. Upon release, the system “works” (and it may be stable). Hurray!

In the post delivery phase, as the (always) unheralded maintenance team starts adding new features without understanding the system’s limitations and bottlenecks, the structural and behavioral integrity of the beast starts surely degrading over time. Scarily, the rate of degradation is not constant; it’s more akin to an exponential trajectory. It doesn’t matter how pristine the original design is, it will undoubtedly start it’s march toward becoming an unlovable “big ball of mud“.

So, how can one slow the rate of degradation in the integrity of a big system that will continuously be modified throughout its future lifetime? The answer is nothing profound and doesn’t require highly skilled specialists or consultants. It’s called PAYGO.

In the PAYGO process, a set of lightweight but understandable and useful multi-level information artifacts that record the essence of the system are developed and co-evolved with the system software. They must be lightweight so that they are easily constructable, navigable, and accessible. They must be useful or post-delivery builders won’t employ them as guidance and they’ll plow ahead without understanding the global ramifications of their local changes. They must be multi-level so that different stakeholder group types, not just builders, can understand them. They must be co-evolved so that they stay in synch with the real system and they don’t devolve into an incorrect and useless heap of misguidance. Challenging, no?

Of course, if builders, and especially front line managers, don’t know how to, or don’t care to, follow a PAYGO-like process, then they deserve what they get. D’oh!

Pay As You Go

October 21, 2009 7 comments

An age old and recurring source of contention in software-intensive system development is the issue of deciding how much time to spend coding and how much time to spend writing documentation artifacts. The figure below shows three patterns of development: BDUF, CADOB, and PAYGO.

Pay As You Go

Prior to the agile “revolution“, most orgs spent a lot of time generating software documentation during the front end of a project. The thinking was that if you diligently mapped out and physically recorded your design beforehand, the subsequent coding, integration, and test phases would proceed smoothly and without a hitch. Bzzzt! BDUF (bee-duff) didn’t work out so well. Religiously following the BDUF method (a.k.a. the waterfall method) often led to massive schedule and cost overruns along with crappy and bug infested software. Bummer.

No Bee Duff

In search of higher quality and lower cost results, a well meaning group of experts conceived of the idea of “agile” software development. These agile proponents, and the legions of programmers soon to follow, pointed to the publicly visible crappy BDUF results and started evangelizing minimal documentation up front. However, since the vast majority of programmers aren’t good at writing anything but code, these legions of programmers internalized the agile advice to the extreme; turning the dials to “10”, as Kent Beck would say. Citing the agile luminaries, massive numbers of programmers recoiled at any request for up front documentation. They happily started coding away, often leading to an unmaintainable  shish-CADOB (Crappy Architecture and Design Out Back). Bozo managers, exclusively measured on schedule and cost performance by equally unenlightened corpocratic executives, jumped on this new silver bullet train. Bzzzt! Extreme agility hasn’t worked very well either. The extremist wing of the agilista party has in effect regressed back to the dark ages of hack and fix programming, hatching impressive disasters on par with the BDUF crews. In extreme agile projects where documentation is still required by customers, a set of hastily prepared, incorrect, and unusable design/user/maintenance artifacts (a.k.a. camouflage) is often produced at the tail end of the project. Boo hoo, and WAAAAGH!

As the previously presented figure illustrates,  a third, hybrid pattern of software-intensive system development can be called PAYGO. In the PAYGO method, the coding/test and artifact-creation activities are interlaced and closely coupled throughout the development process. If done correctly,  progressively less project time is spent “updating” the document set and more time is spent coding, integrating, and testing. More importantly, the code and documentation are diligently kept in synch with each other.

An important key to success in the PAYGO method is to keep the content of the document artifact set at a high enough level of abstraction “above” the source code so that it doesn’t need to be annoyingly changed with every little code change. A second key enabler to PAYGO success is the ability and (more importantly) the will to write usable technical documentation. Sadly, because the barriers to adoption are so high, I can’t imagine the PAYGO method being embraced now or in the future. Personally, I try to do it covertly, under the radar. But hey, don’t listen to me because I don’t have any credentials, I like to make stuff up, and I’ve been told by infallible and important people that I’m not fit to lead 🙂

The only way to learn how to write is by wrote.

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