On Mon, Apr 16, 2012 at 10:56 AM, Jonathan S. Shapiro <[email protected]>wrote:
> Count either instructions or unit numbers. I'm not sure about IOS devices, > but every other mobile device is running a capability microkernel under > those OS's. Most of those qualify as "end user systems". > There is no reason to debate facts, and this is quite a large tangent from where we started, but I'm curious about what facts lead to our differing view of this situation. My definition of Microkernel <http://en.wikipedia.org/wiki/Microkernel> is "hardware drivers live in hardware-protected-spaces and communicate via IPC", such as pure Mach 3.0, (some parts of) NT 3.51, QNX, QNX Neutrino, and more recently hardware-enforced applications of L4. AFAIK... ...NT 4.0+ and Nextstep/openstep/macOS-darwin admitted defeat to drivers outside ring0 and pulled them into the macrokernel for performance. .... which means all desktop WinNT4/Vista/W7, OSX/Mach-BSD, plus smartphones running Android/Linux and iOS/Darwin all load drivers into the privileged space (ring0 equivilent) and are effectively macro- kernels.... this is the source of my comment that "most" systems are macrokernels. ....non-smartphones mostly don't have an MMUs, and thus they can't be evaluated as a micro-or-macro kernel based on this idea of MMU protection -- they are a single-address-space non-protected embedded system (basically one giant macrokernel system). ....QNX and QNX Neutrino are among the commercial MMU protected true-microkernels, and I beileve they are Single-Address-Space-Operating-Systems. Some quick searching found this research project experimenting with an L4 version of Darwin<http://www.ssrg.nicta.com.au/publications/papers/Lee_Gray_06.pdf>, which used an L4 hypervisor to offer microkernel style protections, but a cursory glance looks like they took the QNX SASOS route.. and it's just a research project. I'm curious what body of "every other mobile device" have hardware isolated driver processes? Or are we talking about a different definition of microkernel? > I can also make a strong case that every direct-on-hardware virtual > machine solution is a microkernel. That's certainly a fair description of > Hyper-V. > What is the definition of microkernel that reaches this conclusion?
_______________________________________________ bitc-dev mailing list [email protected] http://www.coyotos.org/mailman/listinfo/bitc-dev
