Oh OK I'm starting to understand now. Thanks so much for clearing that up!
Sorry for being dense - but I just want to make sure I understand fully - the end result of the COBALT kernel build process (following instructions here: https://xenomai.org//installing-xenomai-3-x/#Configuring_and_compiling_the_Cobalt_kernel) is that the original distro kernel (Ubuntu kernel in my case) is actually replaced by the vanilla kernel? I see that they say something to that effect here (mention of replacing the distro kernel with a vanilla kernel): https://xenomai.org/2014/06/running-xenomai-on-virtualbox/#Host_Compiling_kernel_and_Xenomai If this is the case, what step during build / installation is the distro kernel image actually replaced? The last step I see in the build process for x86 arch is "make bzImage modules"... Does this step actually swap out the kernel image? Is a reboot necessary then to load the new kernel? I don't see a reboot mentioned in the docs. On Fri, Nov 3, 2017 at 1:23 PM, Lennart Sorensen < [email protected]> wrote: > On Fri, Nov 03, 2017 at 01:16:38PM -0500, Danrae Pray wrote: > > Ok great - my followup question then is, if the COBALT kernel is itself a > > modified linux kernel and it's the COBALT kernel that's patched with > ipipe > > (no patch is applied to the host kernel), how do POSIX API calls in > > user-space code get mapped to the appropriate system call in the COBALT > > kernel instead of the host linux kernel (in my case Ubuntu distro > kernel)? > > Does this magic happen at compile-time for the xenomai applications? > > When using xenomai, you are not in any way using your distribution kernel. > You could uninstall it and have no problem. > > Xenomai in dual kernel mode (cobalt) requires running a kernel that is > patched with xenomai/ipipe support. That is a linux kernel with extra > features added. The dual doesn't mean it is running your distribution > kernel and a cobalt kernel at the same time. It means you are running a > kernel that supports running normal linux applications at the same time > as it can run real time domain applications (using different process > scheduling and system call interfaces). > > In theory, someone could try to convince the main linux kernel to accept > the ipipe and xenomai patches to get mainlined and always included, > but I don't think anyone is trying to do that at this time. If that ever > happened (no idea if it would have a chance of ever being accepted), > then you would be able to run xenomai on a default kernel, if it was > built with the right config items enabled. > > -- > Len Sorensen > _______________________________________________ Xenomai mailing list [email protected] https://xenomai.org/mailman/listinfo/xenomai
