Wednesday, April 18, 2012

Programming as an Individual Activity

I've decided to come back to Weinberg's classic 'The Psychology of Computer Programming' since it is at the heart of why I took up writing about programming in the first place.  At my first job oh so long ago, it was obvious that we were nowhere close to a solution to programming-in-the-large.  With applications small enough to be written by a single developer we could manage to deliver software that works, maybe it was inefficient or clunky but it worked well enough.  Sure large systems were built using the waterfall approach but they would invariably overrun both their budget and their schedule.  The industry was by no means young, even though the PC revolution was in full swing, the underpinnings had already been discussed ad nauseum. You could dismiss the waterfall method but would still be left with the same questions, 'what do they want?', 'how do we build it?', 'how long will it take?', and so forth.  The Agile or Lean movements have been able to change the discussion to ask 'what is the smallest amount of work that we need to address at one time' and go from there.

I believe that we have been avoiding the most important questions - which are uncomfortable to contemplate - like, "what is the largest single aspect that controls a software schedule?" or "How do we plan a project when the members of the team are not pluggable resources?"

This brings me back to one of the biggest unresolved question of our field, "Why can't we engineer software like we engineer buildings or spacecraft?"  I ask this not for serious comparison since the differences are legion, but rather to point at the single most important advancement in the field of engineering since the advent of the first simple tools (the lever, the wheel, etc), calculus. 

Why calculus you ask? because it gives us a way to plan for infinite variability and still have confidence in the result.  Planning a trip to the moon would be impossible without being able to calculate how much fuel is needed since how much fuel is needed depends upon the weight of the rocket which creates a recursive dependency.

Software will have no equivalent for calculus because the variability comes from the people participating in the project.  Until we accept that people are a first-order component of any software project we will continue to look to silver-bullets, the next development process fad, or the latest new-fangled technology for relief.

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