Re: Re: Re: Re: custom kernel (from NetBSD one)

["Joel CARNAT" <jcarnat%altran.net@localhost>]

Dans l'épisode précédent (Tue, May 10 2005 - 14:46), Manuel Bouyer nous 
apprenait que :
> On Tue, May 10, 2005 at 12:49:04PM +0200, Joel CARNAT wrote:
> > > 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
> 
> I think an interrupt needs to be assigned to the device when it's plugged in
> (but I don't know cardbus very well, I still have only PCMCIA adapters :)
> For PCI devices this is done by the BIOS before the OS is loaded.
> 
> 
> >  access my cardbus because domain0 don't know how to handle this.
> 
> If domain0 can't handle it because of a Xen issue, another
> domainX won't be able to do it either.
>

 OK, I thought it would sound this way.
 
> > 
> > > 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.
> 
> With NetBSD, and in the current state of things, another domain can't steal
> memory from domain0 (and domain0 can't grab unused memory for Xen).
> Xen can do this, but NetBSD doesn't know how to use this yet.
> 

 OK. So I'll have to continue double-booting "the old way" since then.

> >  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).
> 
> Actually I use it as "constantly run several OS on your hardware" :)
> 

 hihi

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