The author writes in the book explicitly "This is a modified version of config.h for compiling a small Minix system with only the options described in the text". This leaves no doubt that the book indeed describes a working microkernel of less than 15kSLOC which can be built and run (even if the "small Minix" lacks a few features). I blieved the author (like generations of other scholars) until I tried to actually build and run it myself.