Comment by rossy

> You do not need to have the same internal structures and the same function names to achieve interoperability

That might be the case for interoperability with a hardware device, but you probably do to make an operating system that's compatible with Windows software and drivers, considering how historically brazen developers are at abusing internal details of Windows. Consider virus scanners that happily patch internal data structures like the SSDT, or other programs that detour a bunch of API functions, then expect those functions to be called in a specific order when a different API function is called, or programs that just reach into stack frames they don't control and pluck out values[1]. (There are some other good ones in that link.) Windows takes pains to be compatible with insane programs like this, so you could argue that copying weird implementation details like this is necessary for interoperability.

[1]: https://devblogs.microsoft.com/oldnewthing/20031223-00/?p=41...