msync() and subtle behavioral tweaks

I am surprised this did not come up in the article. Maintaining backward compatibility with possibly existing old programs is relevant, but is it really more important than making sure the kernel behavior matches the API documentation so that *future* programs will behave as expected?

The other alternative would of course be to deprecate the old calls and replace them with newer ones that do what you'd expect from the documentation and then carefully document all the ways in which the old syscalls don't actually do what they advertise. This alternative sounds horrible in a very Redmondesque way.