Subject: Re: Dumping autoconf info from DDB
To: der Mouse <mouse@Rodents.Montreal.QC.CA>
From: Eduardo E. Horvath <>
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
	"I need to find a pithy new quote." -- me