Subject: Re: Dumping autoconf info from DDB
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Eduardo E. Horvath <eeh@one-o.com>
List: tech-kern
Date: 02/16/2000 09:46:02
> > Strictly speaking, "files" file tree and configuration file
> > tree are not really trees. They are DAGs rather than
> > trees.
>
> I'm not sure what it is you're saying are DAGs, but it sounds as though
> you're talking about the device configuration tree. Well, this sure
> doesn't look very DAGlike to me:
>
> ## SBus expander box
> xbox* at sbus? slot ? offset ?
> sbus* at xbox?
>
> (Those lines are taken from the sparc GENERIC config.)
>
> The tree of devices actually located during autoconf, that's a DAG -
> but it's a tree, so presumably that's not what you're talking about.
While what you're saying is true, and devices are in a tree structure
most of the time, this is no longer true with multi-pathed devices.
Multi-pathed devices are currently limited to fibre-channel disks and
some dual ported SCSI RAID boxes, but if
FutureIO^H^H^H^H^H^H^H^HSystemIO^H^H^H^H^H^H^H^HInfiniband ever
catches on, we'll be seing lots of devices that are available over
multiple paths.
I don't think NetBSD really supports this sort of thing now. We
probably just see multiple driver instances.
=========================================================================
Eduardo Horvath eeh@netbsd.org
"I need to find a pithy new quote." -- me