Pulling slabs out of struct page

> Windows and most forms of Un*x have kernels written primarily in C. (Windows 3.0 apparently rewrote a bunch of stuff from C into assembly.)

This is true, but Microsoft historically has not made a very strong effort to distinguish between "the kernel" and "the rest of Windows." To some extent, this is an arbitrary line-drawing exercise. For example, you could take the position that every process which runs as SYSTEM is the Windows equivalent of a kernel thread, and therefore large chunks of the Windows kernel are actually written in managed languages like C#, but I imagine some people would violently disagree with that characterization.