Software factories are truly excellent. They are highly reliable, with an error rate near zero. But here's the catch: software factories may be something different than what you think they are.
What Are Factories?
We all know what factories are.
Factories have played a major role in creating the modern world, by magnifying the effort of humans with machines and power.
What are Factories Conceptually?
The purpose of a factory is to produce identical copies of a thing you already have and know how to build. Henry Ford's factory didn't produce the very first Model T -- his design engineers did that.
Then they created a factory to churn out lots of copies of the original Model T. Everyone credits the Ford factory with producing cars at low cost. All factories accomplish their core function of producing copies at low cost by replacing labor with machines, and by reducing the amount and the skill of the remaining labor.
In addition, huge amounts of effort have been poured into factory cost-effectiveness and quality. Supply-chain optimization (how to most effectively get the inputs to a factory) is well-understood at this point. Similarly, both the theory and practice of factory output optimization is highly advanced. Methods for assuring consistent high quality have also been developed, starting for example with statistical process control.
The Dream of the Software Factory
We all know that software departments aren't very good at churning out great software. Wouldn't it be great if we could build a factory for software -- a factory that spits out great, high-quality software, on time and on budget, just like all the other factories?
No need to dream -- it's been done! There are big companies behind these factories, there are lots of books about how to build them, scary books about how it's being done better in Japan, everything you'd want.
Of course, when you look more closely, it's all hype. Most software isn't built in that kind of software factory; if it were, they'd have long since taken over software development, and no such thing has taken place.
The Reality of the Software Factory
Fortunately, there really is a software factory. It's effective, efficient, and it's quality is so near to 100% that it's not worth measuring. Furthermore, software factories are widely used -- they're so much a part of programming life, that no one thinks much about them.
One of the most widely used software factories is the cp utility. This amazing utility does exactly what a factory is supposed to do -- it makes you an exact copy of the thing you want to have. Amazing! This factory is also high adaptable. If you change what it is you want to churn out, it can still make a copy of it.
I wish the cp utility worked for cars. If it did, I could point it at my car and it would give me an identical copy. I could then make changes to my car, sic ol' cp on it again, and shazaam -- a copy of the modified car! Cool! Sadly, cp doesn't work on cars (yet) -- it only works on software -- though let's not forget it also works on data, which isn't too shabby...
Factories and Software
I can only hope that people keep coming back to comparing the process of building software to a factory because computer software is so consistently bad. The motivation must be great indeed for so many people to fall for such an obviously flawed metaphor.
After all, factories are for building copies of things that are fully known and understood -- like Model T cars -- things that have already gone through an extensive design and prototyping process. Ooohh -- I like that -- let's make lots of them! Kind of like the iPhone, right? Foxcon didn't get a call from Steve Jobs asking them to start cranking out iPhones until the Apple design engineers had already designed and built them. That widely-reported last-minute switch of the glass surface of the phone happened after Steve played with the prototype and didn't like it -- before the factory started doing its thing.
So repeat after me: designing is what you do to create the first copy of something; if you like it, a factory is used to crank out copies.
If you like a piece of software, cp (or the relevant copy utility) is all you need to make a copy of it! The only reason software engineers get involved is if you want something different. For which a "software factory" as properly understood is simply not relevant.
There's good news: Software factories exist! They are universally used in the software community! They work: they work consistently; they work quickly; they work flawlessly. Be happy.