Originally posted by strobe
The Darwin kernel, xnu, is not a microkernel. Furthermore whether it is or isn't a microkernel has absolutely nothing to do with what filesystems it supports or how easy it would be to support a new filesystem.
MacOSX uses the Mach 3.0 kernel. this is a microkernel. in fact, this is _the_ microkernel. windows NT-2000-XP also uses a microkernel. the GNU system (AKA GNU/HURD) also uses a microkernel, the mach 3 microkernel, the same as Mac OS X.
the darwin implementation of Mach 3.0 is known as xnu.
by the way, strobe, having no native filesystems, and having dynamically loadable modules, while no definitive, does go a long way towards making a kernel a microkernel. every monolithic kernel has FS support hardwired in.
furthermore, whether or not it is a microkernel has _everything_ to do with how easy it is to add filesystem support. in fact, this was the whole principle behind the microkernel design. to make the kernel modular and extensible. it is much much easier and safer to add a filesystem module to a microkernel than to hardwire a new filesystem into a monolithic kernel. due to the obvious superiority of this architecture, even most monolithic kernels today have some support for dynamically loadable drivers, and therefore share some features with microkernels.
Originally posted by strobe
I don't see what that has to do with microkernels.
Umm... that is practically the definition of a microkernel.
Originally posted by strobe
Modules thus have nothing to do with microkernels.
Microkernel (from nightflight): An approach to operating system design emphasising small modules that implement the basic features of the system kernel and can be flexibly configured.
strobe: modules have quite a lot to do with microkernels. in fact they are the defining characteristic of a microkernel.
strobe, i am having my doubts as to whether you know what you re talking about, apropos kernel design. you should not be quite so aggressive in your posts, claiming someone does not know what
he is talkign about unless you are truly an expert, you know?
now as to whether the fact that OSX has a microkernel will help some end user, it is not likely. but remember, the easier it is for developers to add features, the more likely it is to happen, and that benefits our end user. and ease of extensibilty is the major force in the microkernel design.