Make the Invisible More Visible
Many aspects of invisibility are rightly lauded as software principles to uphold. Our terminology is rich in invisibility metaphors; mechanism transparency and information hiding to name but two. Software and the process of developing it can be, to paraphrase Douglas Adams, "mostly invisible".
- Source code has no innate presence, no innate behaviour, and doesn't obey the laws of physics. It's visible when loaded into an editor, but close the editor and it's gone. Think about it too long and, like the tree falling down with no one to hear it, you start to wonder if it exists at all.
- A running application has presence and behaviour, but reveals nothing of the source code it was built from. The number of pixels Google's home page lights up is pleasingly minimal - the goings on behind the pixels are surely substantial.
- Lack of visible management is synonymous with lack of management. If your project is apparantly on track and one week later it's six months late you have problems, the biggest of which is probably not that it's six months late, but the invisibility force fields powerful enough to hide six months of lateness!
- Lack of visible progress is synonymous with lack of progress. If you're 90% done and endlessly stuck trying to debug your way through the last 10% you have problems. Fixing bugs is not making progress. If that were true we could easily introduce more opportunity for progress simply by introducing more bugs. You aren't paid to debug. Debugging is waste.
Invisibility is dangerous. We manage things better when we can see them and see them constantly changing. Our thoughts are clearer when we have something concrete to tie our thinking to. You should take the time and effort to introduce more visiblity. Visibility gives confidence that progress is genuine and not an illusion, deliberate and not unintentional, repeatable and not accidental.
- Writing unit tests provides evidence about how easy the code unit is to unit test. It helps to reveal the presence (or absence) of developmental qualities we'd like the code to exhibit; qualities such as low coupling and high cohesion.
- Running unit tests provides evidence about the code's behaviour. It helps to reveal the presence (or absence) runtime qualities we'd like the application to exhibit; qualities such as robustness and correctness.
- Doing iterative development increases the visibility of development progress (or lack of it) by increasing the frequency of development progress evidence.
- Doing incremental development increases the visibility of project progress (or lack of it) by increasing the frequency of project progress evidence.
Faith is belief without evidence. I don't recommend faith based development. It's better to develop software with plenty of regular visible evidence.
By Jon Jagger
This work is licensed under a Creative Commons Attribution 3
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