Maybe I'm wrong, but I always thought that the "classic" description of a microkernel was one that implemented not only device drivers, but filesystem drivers a

Maybe I'm wrong, but I always thought that the "classic" description of a microkernel was one that implemented not only device drivers, but filesystem drivers and possibly other key components in userspace (memory manager?) as well. At least that is how I remember MINIX 1.0 as described in the Tanenbaum book. I appreciate there is a lot of grey area with microkernels, and a lot of hybrid designs these days, since as was the case with Mach/XNU/Windows NT, "pure" microkernel designs have often shown less than optimal performance due to additional context switching.