Why is Software So Complex?

Q: Why is most modern software so mindbogglingly complex, with multiple layers of abstraction stacked on each other? Why do they not make simple, efficient software like they used to earlier?

This question was asked on Quora recently. I answered that it is due to a few major reasons:

1. Code Maintenance

There’s an old humor article that has circulated online for many years, titled, “If Architects Had to Work Like Programmers.” It’s written as if it’s a letter from a homebuyer who wants an architect to build a house. Here’s an excerpt:

“Please design and build me a house. I am not sure of what I need, you should use your discretion. My house should have between two and forty-five bedrooms. Just make sure the plans are such that the bedrooms can be easily added or deleted. When you bring the blueprints to me, I will make the final decision of what I want. Also bring me the cost breakdown for each configuration so I can arbitrarily pick one.”

This is humorous because it sounds like the way programmers are given their software requirements. Because software can be modified after it is created, the employer assumes it’s easy to do that, and that they don’t need to be specific about what they want.

People in the software development field over many years have tried their best to accommodate this, by creating more and more abstractions so that the pieces of software can be altered, combined, upgraded, or swapped out more easily.

The employer wants this because it enables them to get software on an affordable schedule, without forcing the employer to write detailed specifications that they probably don’t know in advance anyway.

The programmer wants this because they want to remain employed.

2. Code Reusability

A good way to increase code quality without increasing the schedule is to write less bespoke code, but instead use more code that has been written and tested well prior to your project. We call these libraries, frameworks, templates, or code generators.

You’ve probably used Lego toys, where you can build elaborate models using simple reusable bricks or other specialty pieces. You can build practically anything by using enough bricks. There are also some specialized shapes, and lots of guides showing you how to combine them to build the desired models.

Image: Queen Mary model in Lego.

It’s a similar concept to code reusability. Software development then becomes an activity of learning all the different pieces and ways to use them together.

The code is reusable because of abstractions. Like the Lego pieces that use standard dimensions and connecting buttons so they can be fastened to other pieces.

3. Features, Features, Features

I once developed an app for a manager who was very decision-challenged. Every time I would ask him, “do you want the app to behave this way or that way?” I was often asking about two alternatives that were mutually exclusive. For example, do you want the report to arrange categories of data in rows or in columns?

He would always answer, “both.” He didn’t know how to choose, and he was afraid of making the wrong choice. So he asked me to implement both alternatives, and make the software configurable. He wanted to keep his options to change his mind later as often as he wanted to.

This at least doubled the work to implement the code, and doubled the testing needed to assure it works.

But it was worse — every time he said, “both” this doubled the number of test cases, because I had to assure that a new feature worked with every combination of alternatives for the past features.

Programmers can’t say “no” when their employers want some features. They can say, “okay, but here’s what it’ll cost in time and money, do you still want it?”

2 Replies to “Why is Software So Complex?”

  1. Agreed. Good points all around and thanks for the reminder of the house architect metaphor.

    You can make software so configurable as to just provide the programming language and say your done! But even that really’s not enough since you also have to provide the libraries, dev, test, integration environments, deployment frameworks, etc.

  2. >Why do they not make simple, efficient software like they used to earlier?

    I’ve been a programmer for 35 years and I have never experienced this. It’s true we’ve swapped clever hacks that required deep knowledge of processors for an avalanche of modules that are never quite reusable, but I’ve never been involved in a real world project that wasn’t ugly as sin underneath.

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