Subject: Re: Re: Re: custom kernel (from NetBSD one)
To: Manuel Bouyer <bouyer@antioche.lip6.fr>
From: Joel CARNAT <jcarnat@altran.net>
List: port-xen
Date: 05/10/2005 12:49:04
Dans l'épisode précédent (Tue, May 10 2005 - 11:35), Manuel Bouyer nous apprenait que :
> On Mon, May 09, 2005 at 09:17:54PM +0200, Joel CARNAT wrote:
> > On Mon, May 09 2005 - 16:27, Manuel Bouyer wrote:
> > > On Sat, May 07, 2005 at 06:07:16PM +0200, Joel CARNAT wrote:
> > 
> >  I just tried boot xenlive iso and the linux domain0 don't see it.
> >  One trouble is that it is atheros and Linux does not know them straight :(
> > 
> >  Extending this hardware question, I planned to use Xen to use Linux|FreeBSD
> >  IEEE DV cam support. I'm wondering if this will work... As it seems Xen is not
> >  100% like the domainX system (in terms of hardware support).
> 
> For PCI devices, it's equivalent, as long as there isn't interrupt routing
> issues.
> 

 I don't get how cardbus is different from USB/IEEE in terms of
 interrupting. It would be weird to have to run a domainX NetBSD to
 access my cardbus because domain0 don't know how to handle this.

> >  
> >  Does it make sense to run Linux|FreeBSD in domainX if NetBSD/Xen (in domain0) don't
> >  support whatever hardware (DV cam recorder, USB umass for digital camerai or even ATI
> >  Linux drivers) ?
> 
> Yes, as you can hide some devices from domain0 and make them available to
> other domains. I'm not sure how this would work for the display adapter
> and keyboard/mouse, though.
> 
 
 Display is really optionnal, my real needs would be accessing my DV/DC
 without quitting NetBSD. This makes me think of another thing... about
 memory use, especially available memory between domains.

 As I understand it, domain0 get xMo for grub conf. domainX get yMo from
 their "boot config file". But I will use domainX not that often. That
 is to say, if I give 100% of my RAM to domain0, will domainX will be
 able to "steal" a bit of it to run ? Or do I have to configure 80% of
 my RAM to let domainX use the leading 20% ? This is 20% of my RAM is
 unuseable, most of the time.
 I know RAM is cheap, but not on laptop :)
 This makes me think (if the previous is correct) that Xen is more a
 "constantly run several OS on your hardware" rather than "start another
 OS when needed without rebooting" (the same way VMware or wine can be
 used).

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