# Kexec into FreeBSD



## gurtixunix (Dec 29, 2016)

Hello everyone,

I can't find any confirmation that someone already accomplish this.
It is possible to kexecing from Linux into FreeBSD?

Thanks


----------



## ANOKNUSA (Dec 29, 2016)

You will have to clarify what you mean. If what you are asking is whether you can use kexec to replace a running Linux kernel with the FreeBSD kernel, the answer is most assuredly "No."


----------



## gurtixunix (Dec 29, 2016)

Yes that's exactly what I meant
thank you for the clarification
Can you please explain why its impossible or what needs to change to allow this?


----------



## ANOKNUSA (Dec 29, 2016)

gurtixunix said:


> Can you please explain why its impossible or what needs to change to allow this?



I have to surmise that the idea that there would even be a benefit to doing this is purely the product of "the Linux mentality." There are a lot more pieces to an operating system than a kernel, and they all need to work in concert to actually achieve anything worthwhile. The kernel is not the sole defining component of the system, and merely swapping out a Linux kernel for a FreeBSD kernel, while leaving everything else as it is, is not likely to gain you much (if anything). The very idea of even trying this could pretty much only exist in the Linux world.

More importantly, the Linux and FreeBSD kernels are fundamentally distinct pieces of software. Operating system kernels are not interchangeable. The Linux and FreeBSD kernels obviously have a fair bit in common with each other from a theoretical point of view, and there are projects that have gotten the GNU userland to run on top of the FreeBSD kernel. But when it comes to swapping kernels in and out, you may as well ask why you can't use kexec to switch to the NT kernel or the Mach kernel. It is just technically infeasible, and it is doubtful whether there would be any good reason to try.


----------

