[failuser]

Does it need to be 50 million lines of code? When you design with security in mind you might have to prune old code and drop some risky optimizations, probably drop some features. Using a higher-level language might help reduce the line count as well at the cost of performance and memory consumption.

[chevill]

>Does it need to be 50 million lines of code?

Probably not and they should try to reduce the size if it makes sense. However, if all of the OS's I listed are above 10 million lines even in the best case scenario a modern operating system isn't going to be anything less than an overwhelmingly large and complex program.