March 16, 2018

...Learn TDD with Codemanship

Lamenting the Golden Age of High-Integrity Software That Never Came

When I was a much younger programmer, I read a paper that had a big impact on the way I thought about software integrity.

Up to then, I - like so many - believed that "software has bugs". It seemed inevitable. Because all the software I'd seen had bugs. And all the software I'd written had bugs. We just have to live with it, right?

And then along came this paper on a thing called Cleanroom Software Engineering, and my mind was blown.

IBM wrote a COBOL pre-compiler that had about 85,000 lines of code and zero bugs reported in production. Not one. Ever. And what really struck me is that - bearing in mind how primitive dev tools were in the 1980s - it only took a team of six, achieving an average dev productivity that was measurably higher than the industry average. Also, the cost of maintaining the product - typically a lot higher than the cost of initial development - was relatively low; just one developer-year per year. Because nobody was bug fixing.

Now, of course, compared to software today 85 KLOC isn't much. But it's not insignificant, statistically. Maybe an equivalent product today would have 20x as much code. But what's 20x zero?

A single paper turned my whole worldview about software integrity (vs. productivity) upside-down. I've been lucky enough to experience this kind of approach - not specifically Cleanroom, but along similar lines - since, and seen the results for myself. Seeing is believing, and - praise Knuth! - I'm a believer!

So you can probably imagine my frustration to see how, 20 years later, the "software has bugs" paradigm still dominates. Who out there is producing very high-integrity code? Vanishingly few. I've waited and waited for high-integrity development techniques to catch on. I've even stirred the pot a few times myself with attempts at training products and talks with various publishers about a book that updates the ideas for the hipster Agile generation. To no avail. Still, vanishingly few are interested.

It's not as if there isn't a compelling business case. More reliable code, for little to no extra cost (you might even save time and money)? Lower maintenance costs? Happier customers? A world of digital stuff we can rely on? What's not to like? It's not as if these techniques are incompatible with Agile, either. I've done both at the same time, for real.

But for every person like me out there selling the dream, there are 10 more actively briefing against it. "Quick and dirty". "Move fast and break stuff". "Perfection is the enemy of good enough." Etc etc etc.

It's an easy sell to managers who don't understand the relationship between quality, time and cost. Cut some corners, get there sooner, save some money. A much harder proposition is "take more care, get there sooner, save some money". Bosses don't believe it. Heck, most devs don't believe it, despite the mountain of strong evidence to back it up.

I still live in hope that - one day - high-integrity software will go mainstream. The tools and techniques are not, despite what you may have heard, rocket science. Most devs are smart, and most devs could learn to do this. I did, so it can't be that difficult.








Posted 1 month, 4 days ago on March 16, 2018