On Tue, Oct 27, 2009 at 8:05 PM,
<address@hidden> wrote:
Not sure what you are trying to say here. Both Coyotos an Viengoos do
resource management in userspace components...
Correct.
, but need the right kernel
primitives to be able to account resource usage and enforce the
distribution; and as the models differ quite a lot, so do the necessary
primitives AIUI.
I don't think this is correct. Concrete example or evidence, please?
> I don't think Neal made a bad choice, going with an established kernel
> (pistachio) as a base makes more sense than getting roped into
> maintaining one yourself (which may have happened had he used
> Coyotos), all things being equal.
L4 was only (mis-)used as a hardware abstraction in the prototype
implementation of Viengoos. There is now also a proper native x86_64
implementation. It isn't based on L4 anymore -- and conceptually, never
really was.
Neal made a good choice prototyping ideas on a pre-existing substrate. Microkernel construction, at this point, isn't really where the new value lies. Once he had a set of ideas he was ready to pursue, it made sense to fill in the blanks.
My one concern with Viengoos -- and I have expressed this to Neal many times -- is that in the pursuit of better resource arbitrage Neal has given up resource isolation, and there are fairly important (and unfortunate) security consequences for that. It is possible that these can be addressed, and it is fair to experiment on one thing at a time, but it needs to be clearly understood that Viengoos is an experimental kernel, and that it is *not* suitable in its current form for production use.
shap