Re: [Adeos-main] Using ADEOS to run multiple Linux kernels

[Jan Kiszka <jan.kiszka@domain.hid>]

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Jonathan Day wrote:
> Hi,
> 
> According to the white papers and other documentation
> on the ADEOS site, it is possible to use the ADEOS
> nanokernel to run multiple kernels in parallel.
> However, what I am not entirely sure on is how you
> would actually do so.
> 
> What I am wanting to do is run two Linux kernels in
> parallel, minus the overheads of virtualization (I
> don't need it), where the only requirements are that
> if one Linux kernel crashes, it won't take out the
> other and that there's some way of restarting a
> crashed kernel.

I guess you are rather looking for para-virtualized Linux over something
like the Xen hypervisor. This comes with some overhead, but it is fairly
low. The point is that you need memory protection for crash recovery -
otherwise you risk that the crash corrupts memory of the backup kernel.
And with memory protection comes the (para-)virtualization overhead.

In contrast, Adeos, also in its broader original design, is intended to
run multiple kernel _cooperatively_, and that conflicts with your
requirement of crash isolation.

> 
> The documentation I can find suggests that ADEOS would
> be perfect for the job. It's lightweight, doesn't have
> anything I don't need, and is designed to run multiple
> kernels within it. The only bit left is to find an
> example, a HOWTO, or some other information on how I'd
> actually do something like this.

AFAIK, this vision of the paper always remained a vision. In practice,
the non-root domains are always some specialized, cooperating real-time
kernels.

> 
> Can anyone give me a recommendation on where I'd find
> the information I'd need?
> 
> Jonathan
> 

Jan


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