Date: Tue, 25 Jan 2005 16:25:33 +0100 From: "Poul-Henning Kamp" <phk@phk.freebsd.dk> To: Robert Watson <rwatson@freebsd.org> Cc: "M. Warner Losh" <imp@bsdimp.com> Subject: Re: Devd event from GEOM? Message-ID: <86404.1106666733@critter.freebsd.dk> In-Reply-To: Your message of "Tue, 25 Jan 2005 15:22:37 GMT." <Pine.NEB.3.96L.1050125150800.3036C-100000@fledge.watson.org>
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In message <Pine.NEB.3.96L.1050125150800.3036C-100000@fledge.watson.org>, Robert Watson writes: >The interesting question becomes how you map between levels of >abstraction: many consumers of device event information don't really care >about the device and the route by which messages get to it from the CPU. >They care about the abstraction layered over the device, and the events >that occur in relating one object in an abstraction to another object, >perhaps involving topologies that have little to do with the physical >device topology. This raise the questions as to whether the newbus >topology is really the most useful place to expose information like GEOM >slicing, volume management of disk devices, and ethernet bonding for >devices that may be physically discovered using newbus. GEOM already has its own mechanism, and given the diversity of what geom classes can do, I don't think trying to shoehorn it into a newbus like view makes sense. >One appealing thing to the current devd protocol design is that different >abstraction layers (classes) can define their own event name spaces, and >each abstraction layer can declare the events it knows about. newbus >announces "I found a route to a physical device", GEOM shouts "And I found >some storage space on it", etc. Right. IMO we just need devfs to add "And here is a thing you can access". -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 phk@FreeBSD.ORG | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
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