Information flow in genode

[Christian Helmuth]

Hi,

On Mon, Aug 11, 2014 at 03:52:53PM +0200, Norman Feske wrote:
> Hi Wolfgang,
> 
> > Service A is pronounces to “init”.
> > “Init” has the capability to Service A (e.g. AHCI).
> > Program B is started.
> > If Program B requests a service (e.g. read something fromAHCI), Init
> > looks up its root list and notifies A that the service is requested, A
> > creates a new capability and passes it to “Init”, which passes the
> > capability further to B.
> >  
> > Is this correct? And does this happen always?
> 
> yes and yes.

Please forgive me that I interfere, but reading your post I'd like to
substantiate Norman's answer a bit. The answer to your second question
depends on the concrete use case. The mediation of session-creation
requests always happens as there is no way around it. But once the
session is created, communication happens directly between server and
client without interposition of the parent. So your example of "read
something from AHCI" has two phases:

  1. Session creation with mediation by the parent creates session
     capability
  2. Client calls the read function via the session capability
     directly at the server.

Regards
-- 
Christian Helmuth
Genode Labs

http://www.genode-labs.com/ · http://genode.org/
https://twitter.com/GenodeLabs · /ˈdʒiː.nəʊd/

Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden
Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth