People should stop bringing up Mach so much. It should never have been the poster child for microkernels. It's poisoned the discourse when there are plenty of a

People should stop bringing up Mach so much. It should never have been the poster child for microkernels. It's poisoned the discourse when there are plenty of alternative examples. Granted, Mach also did some good work in the space, but its shortcomings are emphasized as if they reflect the whole field. More to the point, drivers in userspace is an important distinction between "pure" monolithic kernels and microkernels: the former is optimizing for performance and the latter is optimizing for robustness. It's not about ease of implementation for either. It's quite meaningful to shift on the axis nowadays: it represents a critical pragmatic decision (notice purity is irrelevant). You're right that "higher-level things" such as the networking stack or filesystem are also crucial to the discussion. I think here, too, ease of implementation is not relevant, though.