Ask HN: A 787 Dreamliner has less than 1/10th of the code of a modern car. Why? | Hacker News Reader

Ask HN: A 787 Dreamliner has less than 1/10th of the code of a modern car. Why?

10 pointssanmon31864 comments

Premium class automobile has 100 million lines[1] or of that order, whereas a Boeing’s 787 Dreamliner require less than 1/10th of that. LoC is no measure of complexity of a system but it is still an indicator of how much is going on inside. So what is it that an airplane doesn't have but a modern car has?

[1]http://spectrum.ieee.org/transportation/systems/this-car-runs-on-code

* 2009 link but coming from IEEE, I believe it is credible enough.

*Not sure if it really qualifies to be Ask HN question

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It says right there in the article. The 787 numbers are for avionics and flight systems. The number for the car probably includes the entertainment system, nav system, backup camera, etc all of which runs on some open source OS with hundreds of packages installed. 787's don't run on large numbers of open source packages for avionics and flight control.

> The 787 numbers are for avionics and flight systems

Agreed. 1/10th may seem an exaggeration but given the complexities that one would imagine in 787 in comparison to a car, this seems astonishing. I wonder how many automotive software recalls today are due to avoidable opensource (or any code for that matter) that has low value density, and hence more liability to the manufacturers.

I wonder how many LOC are for dealing with emission tests...

>LoC is no measure of complexity of a system

Agreed but I've often been curious about the complexity myself. I saved a similar discussion on reddit a few years ago. One commenter worked for a company that makes Stability Control Systems for major car manufacturers and this comment really stood out for me:

Like, for instance, BMW wants us to follow this architecture standard that (very simply) requires all function calls between sets of "subsystems" to route through one file. It is currently at around 120,000 lines. That's one file out of the thousands of files we have. We have many "database" files that are thousands to tens of thousands of lines long as well.

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