"Like VMS,[24] Windows NT's kernel mode code distinguishes between the "kernel", whose primary purpose is to implement processor- and architecture-dependent functions, and the "executive". This was designed as a modified microkernel, as the Windows NT kernel was influenced by the Mach microkernel developed by Richard Rashid at Carnegie Mellon University,[26] but does not meet all of the criteria of a pure microkernel."
[...] the strict distinction between Executive and Kernel is the most prominent remnant of the original microkernel design, and historical design documentation consistently refers to the kernel component as "the microkernel".
[0] which I am old enough to remember as an adult and a graduate -- I remember particular criticism from academics in OS design around the time of NT 4.0, which as I (admittedly hazily) recall relaxed some of the distinctive design because 3.5's graphics performance was too poor and the graphics subsystem had to be moved essentially into the kernel.
But anyway: around the introduction of NT [0] there was clear discussion about how the kernel design was informed by the Mach/kernel boundary.
https://en.wikipedia.org/wiki/Windows_NT
"Like VMS,[24] Windows NT's kernel mode code distinguishes between the "kernel", whose primary purpose is to implement processor- and architecture-dependent functions, and the "executive". This was designed as a modified microkernel, as the Windows NT kernel was influenced by the Mach microkernel developed by Richard Rashid at Carnegie Mellon University,[26] but does not meet all of the criteria of a pure microkernel."
https://en.wikipedia.org/wiki/Architecture_of_Windows_NT#Hyb...
[...] the strict distinction between Executive and Kernel is the most prominent remnant of the original microkernel design, and historical design documentation consistently refers to the kernel component as "the microkernel".
[0] which I am old enough to remember as an adult and a graduate -- I remember particular criticism from academics in OS design around the time of NT 4.0, which as I (admittedly hazily) recall relaxed some of the distinctive design because 3.5's graphics performance was too poor and the graphics subsystem had to be moved essentially into the kernel.